First Trimester Screening for Aneuploidy

Wednesday, December 13, 2006

Kenneth F. Trofatter, Jr., MD, PhD

In my November 29, 2006 post, I promised that my “next post” would focus on a discussion of first trimester screening for aneuploidy. It has taken awhile to get back to this, having had a few distractions along the way, but blogging does offer some degree of flexibility and allowance for distractions!

First trimester screening for aneuploidy, or as it is commonly referred to as ‘combined first trimester risk assessment,’ has gained widespread acceptance in other developed nations over the past decade, and is slowly coming into its own here in the U.S over the past couple of years as well. This screening test uses a combination of fetal measurements, maternal blood pregnancy ‘markers,’ maternal characteristics (age, weight, race, family/pregnancy history, and certain medical problems, such as diabetes) and a large, and continuously expanding, data repository to generate risk numbers for trisomy 21 (Down syndrome) and trisomies 13 and 18. The primary measurements of the baby include the ‘crown-rump length (CRL)’ (top of head to bottom of butt) and the ‘nuchal translucency (NT)’ (clear space between the skin and underlying soft tissues of the back of the neck, head, or upper trunk). The wider the nuchal translucency, the greater is the likelihood that the baby has aneuploidy. A special certification process has been developed for performing NT measurements and completion of this in an acceptable fashion is required before access to the database for combined risk assessment can be obtained. The presence or absence of a fetal nasal bone can also be factored into the risk assessment, since the absence of the same (or the presence of one that is smaller than usual) has also been associated with aneuploidy, especially trisomy 21. Separate certification is required for this to be used in the risk assessment process.

The maternal blood samples assess levels of free β-hCG (the ‘pregnancy hormone’ secreted by placental tissues, the trophoblasts) and pregnancy-associated plasma protein A (PAPP-A) (associated with differentiation of the placental trophoblasts). Free β-hCG levels usually decrease after 10 weeks’ gestation in normal pregnancies, whereas they often remain elevated or increase in cases of trisomy 21. Indeed, the difference between these and normal pregnancies increases with gestational age. In contrast, babies with trisomy 21 tend to have lower levels of PAPP-A than normals, but the difference between these and normal babies tends to decrease with gestational age.

For combined risk assessment, the fetal crown-rump length must be between 45 and 84 mm, roughly corresponding to 11-14 weeks’ gestation. The maternal blood screening can be done at the same time the fetal measurements are obtained, or as early as 8-9 weeks,’ and then combined with the fetal measurements when these are performed. The advantage of this latter approach is that a ‘final result’ can be obtained the same day, whereas about a week is required for the former because that is the time required for processing of the maternal blood samples. The test is most reliable (has the greatest combined sensitivity of the NT and blood screens) at the gestational ages between 11 and 12 weeks and this is also the time when it is easiest to obtain the most accurate NT and CRL measurements.

The ‘sensitivity’ of the test relates to the probability if the disease (in this case aneuploidy) is present, the test will be positive. Neither the NT measurement nor the blood tests by themselves have sufficient sensitivity to stand alone as a good ‘screening test’ that would be widely acceptable. At the risk of great over-simplification, combined risk assessment has been shown to have the capability of detecting trisomies 21, 13, and 18 in 85-95% of cases with false positive rates (probability that the test is abnormal, but the baby is not aneuploid) in the range of 5% or less. In our own experience over the past two years, we have not missed a case of one of these trisomies in ‘at risk’ women (women expected to be 35 years or older at delivery), younger women at increased risk for aneuploidy, or who simply wanted reassurance and had this screening performed.

There are distinct advantages to combined first trimester screening. In most instances, it provides early reassurance to ‘at risk’ and even low risk women who undergo the screening process. It also offers the opportunity for early detection of babies with the chromosomal abnormalities noted above, and for detection of other chromosomal abnormalities (and congenital heart defects as a side benefit in babies that may or may not have a chromosomal abnormality) that might also be accompanied by abnormalities of the NT. This allows patients more time to consider their diagnostic and therapeutic options at a time in the pregnancy where privacy and confidentiality are much easier to preserve. At the same time, the cost, sensitivity, and false positive rates are comparable to, if not better than, that of midtrimester screening.

There are also some limitations of first trimester screening that must be conveyed to all women considering this procedure. The test is still just a ‘screening’ test and therefore cannot replace an invasive diagnostic test such as chorionic villus sampling, amniocentesis, or umbilical cord blood sampling for the definitive diagnosis (or not) of aneuploidy. Although ‘false positive rates’ are low, a “positive result” does not mean that a baby definitely has a genetic abnormality. Indeed, many will not. By the same token, a “negative result” does not guarantee the absence of a chromosomal abnormality, other heritable or syndromic problems, or fetal birth defects that are not clearly related to a specific genetic cause. For that reason, even to women who have had ‘reassuring first trimester screening, we offer both maternal serum alpha-fetoprotein (MSAFP) screening at 16 weeks’ and a ‘targeted’ genetic sonogram at 18-20 weeks’ gestation.

In the next (or some time in the near future) post, we will discuss what it means to have an “abnormal” first trimester screen as well as the options for follow-up of the same…

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122 Comments:

At Sun Oct 07, 10:02:00 PM 2007, Anonymous said…

Thanks for putting so much effort into a fascinating and endlessly informative blog!

How reliable is the screening for multiple gestations? Isn't beta-HCG elevated in that case? Or is there sufficient info in the database on twins, triplets, etc. that the differences can be taken into account and reliable estimates of risk can still be made?
At Thu Oct 11, 05:39:00 PM 2007, Kenneth F. Trofatter, Jr., MD, PhD said…

To Anonymous Oct 7: Great question. I will probably use this query in a full post at some point if you don't mind. There is excellent and constantly expanding data in the database for multiples. I do not know the adequacy of this for triplets, but the detection rate in twins ranges between 75-85% at a false-positive rate of 5%. It is actually quite good. I encourage women with twins to have first trimester screening done also because of the possible deection of early evidence of twin-to-twin transfusion sequence in monochorionic twins and congenital birth defects for which all twin pregnancies are at greater risk. Thank you so much for reading and for your question! Dr T
At Fri Oct 19, 02:05:00 PM 2007, Anonymous said…

I am 10 weeks pregnant and scheduled for what my OB calls an "Ultrascreen" in November. It sounds very much like what you are describing but is performed between 11-13 weeks gestation. I will be having it during the beginning of my 13th week due to travel. I requested the earliest screen available due to AMA (I'm 34), and was told this is the the screen I want. Are you familiar with this screen and is the accuracy less effective due to it not being completed within the 1st trimester?

Thank you so much for this wonderful site.

Melissa
At Fri Oct 19, 08:18:00 PM 2007, Kenneth F. Trofatter, Jr., MD, PhD said…

To Melissa Oct 19: You will still be in first trimester when you have the test done. I think the screen is probably a little more reliable at 11-12 weeks, but there is not enough of a difference to worry about that. Remember, it is still just a screening test that does not detect all chromosomal abnormalities or other problems the baby could have. But, the odds are in your favor for a good outcome, so best of luck to you. Dr T
At Mon Jan 21, 11:47:00 AM 2008, Anonymous said…

Thank you for this informative article! Can you tell me if the ultrasound is typically tranabdominal or transvaginal. I would like to mentally prepare myself if it is the former. :) Thank you!
At Fri Jan 25, 10:58:00 AM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Anonymous Jan 21: In most cases we can do the nuchal translucency measurements transabdominally. Of course, a lot depends on how cooperative the baby is! Don't sweat either, you WILL survive the procedure! Dr T
At Sat Mar 08, 11:38:00 AM 2008, Anonymous said…

Dear dr T,
first I want to thank you for this blog.
I did my first trimester screening and these are results:
age at term : 29.5
diabetes : no
Caucasian
weight: 87kg
smoking: no
____________________
free bhcg 105 ng/ml - 2.59 MoM
PAPP-a 1.81 mlU/ml 1.29 MoM
CRL 50mm
NT 1.7mm - 1.26 MoM
____________________
Biochem. risk + NT 1:1723
Double test 1:1029
Age risk: 1:1015
Trisomy 18 risk <1:10 000
____________________

I see that all numbers are ok, except free beta hcg levels, which are very high.
What do you think, what that means?
What can cause beta hcg to be so high?
I know that my ovulation and implantation were late, and I feel when hormones are fluctuating, could it be just momentary...?

Please answer me, I'm very anxious.
At Tue Mar 11, 05:57:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Mar 8: The placental cells (trophoblasts) make the hCG and PAPP-A. Since you have 'healthy levels' of BOTH, perhaps you just have a very healthy developing placenta! The 'risk assessment' is based on the combination of findings, so relax and enjoy your pregnancy. There is no reason to even suggest anything to worry about at this point. Best of luck to you and please let us know how things turn out. Dr T
At Fri Mar 14, 11:28:00 AM 2008, Anonymous said…

I just had my results from the Ultrascreen.
My report shows:
NT(mm):2.7
CRL (mm): 65.7
Free Beta hcg (MOM): 0.98
Percentiles: 50
Papp-A MOM: 0.47
Delta NT: +1.06
Nasal Bone***Present nasal bone is not considered when Down Syndrom risk results are greater than or equal to 1 in 100.
RESULT: Down syndrome after screening 1 in 44--Increased risk
Trisomy 18/13: 1 in 3,402--within range.
AGE: 34 yrs.old

I am saddened by the results and confused by these numbers. What is considered a normal range for each category? What was even more confusing is that when the technician did the sonogram, she said everything looked great, she pointed out three facial bones, including the nose and said that babies with Down Syndrome would not show these bones even at 12weeks 5 days gestation. She seemed very reassuring, said everything seems fine, and knowledgable. She said the pictures were great and the doctor would discuss the results. I don't understand.
At Fri Mar 21, 06:36:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Anonymous Mar 14: The increased risk in your case is probably being driven by the NT measurement and the relatively low PAPP-A when compared to the 'normal' hCG. At this point you still only have about a 2% chance the baby has Down syndrome. With regard to the ultrasound, sometimes baby's that have Down syndrome will look remarkably "normal" until later in the pregnancy. Even the more characteristic abnormalities associated with Down syndrome (A-V canal defects in the heart and duodenal atresia, for example) are not present in all babies and will not be evident at this early gestational age. Keep your hopes up and we will all be pulling for you. Please let us know what you find out. Dr T
At Fri Mar 28, 12:01:00 PM 2008, Anonymous said…

Hi Dr. Trofatter,
This is a great blog, thank you! I've been searching for clues as to what else causes elevated free beta hCG levels (besides trisomy 21) and have gotten only research papers and your blog. I would really appreciate it if you had a moment to look at my case.

My combined screenings came out as follows:
singleton
CRL 63.6mm, GA 12w6d
Overall risk asessment:
Trisomy 21 risk - 1 in 743
Trisomy 13/18 risk - 1 in 14,901
_______________________________

Free beta hCG % 97.5/2.88 MOM
PAPP-A % 40/MOM 0.84
_______________________________

NT 1.2mm (Trisonmy 21 risk 1 in 4764 on this basis alone)
_______________________________
My stats are 33 yo at term, caucasian, 115 lbs maternal weight.

I know one poster already presented with a free beta of 2.59 MOM, but she also had a high level of PAPP-A, where as I do not. You also mention in the main article that hCG levels tend to diverge and PAPP-A levels converge... A midwife at my hospital called me back and assured me you're not allowed to pick one marker out of the screening to be alarmed, but she also couldn't tell me what else could cause such an elevated level of the beta hCG.
Since you mentioned these markers are produced by placental cells, perhaps it's of some interest that the u/s results also indicate a low anterior placenta, and they weren't sure if the umbilical cord had 2 or 3 blood vessels.
Thanks and have a good weekend!
At Fri Mar 28, 12:14:00 PM 2008, Anonymous said…

Hi,
I hadn't seen your article from yesterday when I posted a moment ago. I'm the "33 yo at term caucasian, 115 lbs with free beta hCG MOM of 2.88."
Perhaps it is also of interest that I miscarried and had a D&C a couple months before this pregnancy? (I also had an elective abortion at 19 yo.)
I was 9.5 weeks pregnant when I got into a car accident on 11 Nov. 2007. The next day the abortion was confirmed (CRL correlated with fetal death at 9.5 weeks) and dilation commenced that day with the curretage the next morning. They told me to wait one cycle before trying again, and bingo presto, my LMP was 17-December-2007.
This perhaps explains my weird implantation site (low anterior), but I have no idea if it explains anything else :(
Thanks *so* much for reading.
At Sun Mar 30, 04:38:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Anonymous Mar 28: Sometimes folks just have very 'healthy' placentas and seem to make more hCG! This is commonly seen in some diabetics and in multiple gestations. In your case, however, there is a possibility that because of the short interval between the D&C and the conception of this pregnancy this baby implanted on a denuded (still healing) portion of the endometrium and had growth of the trophoblasts (placental cells) into the myometrium ( muscle of the uterus) rather than just the endometrium alone. Under normal circumstances, there is a balance between proliferation and invasion of the trophoblasts and your body's immune system limiting that growth and invasion. The myometrium is not able to control the growth of the trophoblasts as well as could have been done in the endometrium. (We see this, routinely, with tubal ectopic pregnancies). If this has occurred, it may increase your risk for a placenta accreta wherein the portion of the placenta that has invaded the myometrium does not detach normally following delivery. I don't know for sure in your case, but this is certainly a possibility and one of the reasons I recommend women wait at least 2-3 months after a D&C to get pregnant again. Sometimes we can actually visualize a placenta accreta by ultrasound later in the pregnancy. Good luck to you, thanks for reading, and let us know how things turn out. Dr T
At Thu Apr 10, 12:35:00 PM 2008, Anonymous said…

thanks for the blog! i just found it as i was researching high hcg levels. i'm 29, asian, 5'6"/135lb, and 15w with our first child.

anyhow, i had the nt test done and received the following assessment: nt = 2.7, free beta hcg = 2.77, papp-a = 1.18, T21 risk of 1:46 and T13/18 risk of 1/10,000+. i read in an nih study that chinese women tend to have much higher MoM on the serum markers. have you found that to be true in your experience? could it be possible that i have a "healthy" placenta that's generating so much hcg? i did have a d&c in september and a septate resection at the end of november prior to getting pregnant the cycle following the resection surgery if it helps. also, i am not diabetic (have not been tested for gestational diabetes). i'm very anxious as this is our first child and the my risk for T21 is causing more than just my eyebrows to rise. thank you for your help!
At Sat Apr 12, 12:52:00 PM 2008, Anonymous said…

Dear dr T,
I am an italian pregnant woman and your blog is very interesting. Excuse me for my english mistakes.
I expect my third baby and these are the result of ultra screen:

age: 36
diabetes : no
Caucasian
weight: 66kg
smoking: no
weeks gestation test:12+4
____________________
free bhcg 49.4 ng/ml - 1.82 MoM
PAPP-a 1.1 mlU/ml 0.34 MoM
CRL 71mm
NT 2 mm - 1.13 MoM
____________________
Combination risk Trisomy 21 1:69
Combination risk Trisomy 18 1:10000
Age risk: 1:207

Please answer me, I'm very anxious.

Stefania
At Tue Apr 15, 06:12:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Apr 10: Your ethnicity may be playing a role here, but many laboratories already 'correct' for that. You also could just have a 'healthy placenta' or a placenta that has grown into the muscle layer of the uterus as a consequence of your septum resection. When this occurs it is called a placenta accreta. I am reassurred that the PAPP-A level is very 'normal', so hopefully, on of these other factors is the cause of your abnormal screening results. Let us know how things turn out and thanks for writing! Dr T
At Tue Apr 15, 07:07:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Stefania Apr 12: The test results indicate that you are at increased risk for having a baby with Down syndrome (trisomy 21). The high hCG level combined wih the low PAPP-A level is often found with Down syndrome. Remember, however, the test is just a SCREENING test. It does not sa for sure that your baby has Down syndrome. If you want to find out, you will have to have some form of DIAGNOSTIC test performed, either chorionic villus sampling or an amniocentesis. Good luck to you my friend, let us know what you find out, and thank you for writing all the way from Italy! Dr T
At Fri Apr 18, 05:54:00 AM 2008, Anonymous said…

I was so pleased to find your blog! There is not much information available to those of us who want/need details and technical answers! I have a question about the reliablility of my screening due to the lab dating my blood draw incorrectly. My paperwork states that I was 10w4d for the blood draw, but I was actually 10w0d. I know it's not much difference, but could it change my odds at all? Overall, my final odds were great, but I am a bit concerned about my low Papp-A level (if it rises daily, though, maybe it would've been better if dated correctly???). I am also quite concerned that my results just aren't accurate. What do you think? Here's my information:
Age:37
Caucasion
178 lbs.
non-smoker
letrozole and IUI to conceive
GA@u/s: 12w1d
NT(mm):1.37
free beta hCG MOM:.64
PAPP-A MOM: .44
DS odds: 1/1792
trisomy 18/13 odds: 1/4476
Thank you so much for your time! I am SO ready to let go of my worries and enjoy this pregnancy (as is my poor husband!!!).
At Sun Apr 20, 06:38:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Apr 18: The results are so good, that 4 days should not make a difference. Congratulations and best wishes fo the rest of the pregnancy. Let us know how things turn out! Dr T
At Wed Apr 23, 04:16:00 PM 2008, Anonymous said…

Thank you for all this information. I do have a question. At 11.5 weeks our baby's NT scan result was 5.5 mm. I do not have blood test results and I am not sure if they were done. The same day I was sent for a CVS test. Both the fast result and the cultured result showed a normal karyotype. Our doctor is suggesting we also do an amniocentesis next week (at 15w5d). What are the chances of a normal CVS test result and an abnormal amnio result? An ultrasound at 14w2d showed an NT of 2.4 mm, a good length and nothing out of the ordinary. We are aware that we will have an ultrasound around 20w to examine in depth the baby's heart and look for any structural defects. Is an amnio worth the risk after a CVS? I am 35.
Thank you,
Cathy
At Thu Apr 24, 04:35:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Cathy: It is unlikely that you will learn anything new from an amniocentesis at this point. It is true that sometimes a baby can have a chromosomal mosaicism (two genetically different populations of cells - usually one normal and one abnormal) but that is often picked up by CVS. It is also possble that the CVS grew only your cells, but in mots laboratories today, that is also unlikely and if the chromosome studies came back a normal BOY, then that would be almost impossible! Personally, I would suggest having you wait until you have the targeted ultrasound done at 18-20 weeks before considereing any more invasive studies unless aa physical abnormality of the baby is seen before then. Remember, though, babies can be chromosomally NORMAL and still have major malformations, particularly of the heart. I certainly wish you the best and please let us know how things turn out. Dr T
At Sun Apr 27, 11:02:00 AM 2008, Neil said…

This seems such a helpful blog, and I'd really appreciate some advice. My girlfriend (age 36 next week) has just been for First Trimester Ultrasound and some of the results are below

gestational age = 12wks+1
----------------
Biochemistry
free bhcg 32.000 IU/I (0.6536 MoM)
PAPP-a 3.591 IU/I (1.1845 MoM)
----------------
CrownRump Length 58.6mm
Nuchal T 1.7mm

Adjusted Trisomy 13/18 risk = 1:559
Adjusted Trisomy 21 risk = 1:350

The doctor didn't comment on any of the numbers above, but did mention Ductus Venosus (a-wave) reverse flow and said this increased the Trisomy risks.
He didn't seem overly worried though.

From reading the internet (which maybe we should never have started) we are both now worried that this reverse flow problem seems very very serious, not just for chromosome disorders but generally for the health and development of the fetus.

Are we panicking without reason? Or should we be getting much more advice from the doctors?
There is also high chance of pre-eclampsia (both mother and sister) in my girlfriends family, and we're beside ourselves with worry at the moment. First succesful pregnancy after 2 years trying and things don't sound good.

Any advice would be greatly appreciated.
thanks
At Wed Apr 30, 05:39:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Neil: Oh. I don't know - things sound pretty good to me! The aneuploidy risk are about half your partner's 'age alone' risks and it is sometimes easy to get abnormal ductus venosus waveforms that don't mean anything at this point. Could they if they were real? Sure, but babies can have cardiovascular malformations that are not related at all to fetal chromsomal abnormalities and my suggestion at this point is that you bask in the relief of the reassuring first trimester screen and get a couple of more good ultrasounds along the way to carefully evaluate the baby's anatomy. The family history does put her at increased risk for preeclampsia, but unless there is some predisposing heritable cause, such as a genetic thrombophilia, there is not much you can do about that at this point and it is aproblem we deal with on a daily basis. Uterine and umbilical artery Doppler flow studies can give you a better idea about the 'normality' of the placentation and your doctors can explain why when you ask! Take a few deep breaths and relax. Thanks for reading and let us know how things turn out. Dr T
At Wed May 07, 05:19:00 AM 2008, Anonymous said…

Hi. I am 40 yrs. Had my first trimester screening at 11 weeks. I'm afraid I dont have the blood test results or the NT measurement. However, the doctor said that my age risk for T21 is 1:65. After the screening my risk decreased to 1:98. What would account for that small change in risk? I am still in a high risk group and am contemplating an amnio.
At Fri May 09, 07:19:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous May 7: Without the other information I cannot tell you what is driving your risk, but I bet your age is a primary factor. I often tell my patients with a 1 in 100 risk that they can proceed with amniocentesis or await the results of further ultrasound studies. A completely normal genetic sonogram at 18-20 weeks can reduce your risk as much as 90%. In the end, the choice is yours! Let us know what you decide to do and what you find out. Dr T
At Sat May 10, 06:41:00 PM 2008, Anonymous said…

Hi I'm an indian 23 years old
pregnant 14 weeks
nt scan results
NT-4.3mm;
hcg(mom)-0.49
pappa(mom)-0.71

delta NT:+2.62
GA @ u/s-13 weeks 0 days
crl-68.7mm
DS risk-1 in 120
trisomy 13/18-1 in 72
please guide me understand the results;wats the normal result ?
do I have an increased risk of having trisonomy 13/18 probs.?
At Sun May 11, 03:14:00 PM 2008, Anonymous said…

Hi Dr. T! I have been reading your blog and found it to be one of the most interesting out there. I am pregnant with my 4th child. I have 3 healthy children, (2 miscarriages) one at 9 weeks before 3rd child born and one chemical pregnancy at 5 weeks right before this preganany so no period and then fell pregnant with this baby. I had my NT screen at 12weeks and my stats are:
NT: 1.3 mm
CRL: 58.5 mm
Free Beta: 1.49(MOM)(70th %)
Papp A: 0.54(MOM)(20th %)
Delta NT: -0.21
Nasal bone: Present
Age: 35 at EDC
Maternal wieght I guessed so it could be a bit off: 145lbs.
Downs risk: 1:1,261
18/13 risk 1>10,000

Although, the risk factors calculated by the lab seem good, and my doctors were pleased and didn't recommend invasive testing, I am over analyzing everything myself as I have never had this test done in the past with my other 3 so to hear actual odds given makes my mind go crazy. I guess I would have preferred to hear low risk or high risk as my results rather than the numbers. So when poking around the internet I can't help but see there are women that have similar results of free beta and Papp a (although not exact) but there risk level is a lot more increased than mine. So it got me worried that my Free beta is high and the Papp a seems low. How are my odds seemingly different that others that seem to have somewhat similar numbers but way different risk? do the risk shift a lot by just a few decimals or something? or do different labs have different factors? please advise..thanks:)
At Tue May 13, 06:02:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous May 10: Despite your young age, your high risk for a baby with a chromosomal abnormality (BOTH Down syndrome and especially trisomy 18) is being driven by the high NT measurenment and the relatively low hCG. The PAPP-A is actually in a 'normal' range, but the combination of factors has led to your 'at risk' status for one of these or another chromosomal abnormality. There is also the possibility that your baby is perfectly normal chromosomally, but might have a congenital heart defect that caused the increased NT measurement. Remember, this is still just a SCREENING test, so there is also the possibility that absolutely NOTHING is wrong, but if you want to find out for sure, you should proceed with an amniocentesis. Good luck and let us know how things turn out. Dr T
At Tue May 13, 06:04:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous May 11: Trust the huge database and the computer that gave you the WONDERFUL risk assessment. You will go crazy if you try to dissevt the individual results. Tp put this in perspective, your risk for Down syndrome is less than that of a 20 year old. So, try to get some rest and RELAX! Let me know if I'm wrong, okay! Best wishes. Dr T
At Tue May 13, 06:34:00 PM 2008, Anonymous said…

(From anonymous May 11): Thank you Dr. T for getting back to me so quickly. I will try to relax and enjoy my pregnancy and trust that the lab and database know more than I do:) I will definitely let you know how it goes. By the way this blog is the most wonderful informative site I have stumbled upon. A big reason is because you are so generous in sharing your wealth of knowledge freely with all of us. I know you have helped many relax and gain more insight. Thanks again.
At Wed May 14, 08:29:00 AM 2008, Anonymous said…

Hello,
I just got my results for Trisomy 21:
FBhCG ng/ml: Conc = 89.3 MoM=2.61
PAPP-A mU/1: Conc = 8190 Mom=2.19
CN mm: Conc = 1.4 Mom=0.98

T21: 1/30

My Ultr sound at 12.5wks was completely normal, that with my overall age (44, my sister had a normal baby at 46) my doctor says makes my risk 1:277 and normal would be <1:380.
He wants me to have another Ultra S..in 2wks. Also, I have been taking progestarone since wk5 (vaginally), could this affect my results. I know this is just a screen and doesn't mean my baby isn't normal, but why to these results sometimes occur when the baby is nornal, in that case what do they indicate. Lastly, what are the lastest studies on the risk of having an amniocenteses?

PS: I'm in Suisse at the moment, so not sure why they test only T21 at this point.
At Thu May 15, 05:47:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous May 13: Thanks for the very kind words and best wishes for the rest of the pregnancy! Dr T
At Thu May 15, 05:53:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous May 14: I bet your baby is normal too, but the composite 'risk assessment' is rather scary, isn't it? I think your risk is being droven by your age and the relatively high hCG. What is reassuring to me is that the PAPP-A is also elevated. Screening tests are not perefect and first trimester screening is asscoiated with a 5-10% 'false positive rate'. The risl of the amniocentesis depends on the experience of the person who performs it and any complications you yourself might have beforehand (such as bleeding) that may increase your risk. we tell our patients that the risk is less than 1 in 500 (and honestly may be less than 1 in 1000). Best of luck with the pregnancy and please let us know what you find out.
Dr T
At Fri May 16, 12:00:00 PM 2008, Anonymous said…

Dear Dr.

I just had my results from the Ultrascreen.
My report shows:
NT(mm):1.3
CRL (mm): 58.5
Free Beta hcg (MOM): 2.79
Free Beta %: 97.5
Papp-A MOM: 1
Papp-A %: 50
AGE: 34 yrs.old

My downsyndrome risk reads 1 in 443, my age risk is 1 in 326.

Although my report still shows that the result is within a normal range, I am a little concerned. After doing some research online, seems my Free Beta MOM:2.79 is not within the normal range, I think it is the reason that's causing my risk to be still somewhat high.

Could you help me to interpret my results as well? Do I need to be worried? What other reasons could cause a high Free Beta MOM, and any way I can get it tested again to have some assurance? BTW, I just did my AFP test today.

Thanks,

JC
At Fri May 16, 05:58:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To JC: Your risk assessment results are very good. It is unlikely your baby has Down syndrome. The only thing I would suggest now is a good ultrasound at 18-20 weeks. If that checks out okay, you can reduce your risk at least another 60-80%! RELAX. Thanks for reading and let us know how things turn out. BTW, do not try to dissect the test results. You WILL go crazy! Dr T
At Tue May 27, 12:33:00 PM 2008, Anonymous said…

Dr. T

Thanks a lot for your response.
I just had my ultrasound done at 18 weeks and 4 days, all the measurements show up normal. Though I did not do a 2nd level ultrasound since I am still one year away from 35. My OB did say it further reduces the down syndrome risk but he did not say by what percentage. Should this put my mind to ease, or shall I request for a 2nd level ultrasound to get more detailed measurements?
BTW, what measurements for the ultrasound are we looking at that are related to down syndrome?

Thanks a lot!

JC
At Wed May 28, 04:37:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To JC: It doesn't sound like you need to do anything else. As I said before, a normal ultrasound at this point reduces your risk by more than half. The things we look for on a targeted ultrasound are major birth defects as well as 'soft markers' for aneuploidy such as a thickened nuchal skin-fold, hypoplastic nasal bone or middle bone in the small fingers, comparatively short humerus or femur, etc. I think you should just sit back and enjoy the rest of your pregnancy! Let us know how things turn out. Dr T
At Thu May 29, 08:00:00 AM 2008, Anonymous said…

Dr. T

Thanks for the quick reply and re-assurance! I'll follow your recommendation and just enjoy it :->

JC
At Thu May 29, 08:33:00 AM 2008, anonymous said…

Dear Dr. T,
I have learned so much from this sight. I am 38 and have not received my first trimester screening results yet but have some questions. I don't understand how free beta hcg is calculated. I do know that my beta hcg from regular RE appointments has been dropping since about week 10. Does this mean my free beta hcg has also been dropping? Also this was a pregnancy conceived through IVF/ ICSI how will that affect my serum levels? I read somewhere that it can through them way off? Why? I also had a vanishing twin.
I have one naturally conceived normal child (3 years old) but have had 5 miscarriages in one year. So I am very afraid of amniocentesis even though I have had it before. Does being a habitual aborter affect your risk factor for amniocentesis? I am just afraid due to all these factors my screening results will not be accurate. Thank you
At Thu May 29, 02:34:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To JC May 29: You are welcome and again best wishes! Dr T
At Thu May 29, 06:08:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous May 29: Okay, sit down and take a deep breath and count to 10! There is nothing to get worked up about at this point. Now, to try to answer some of your questions - free beta-hCG is simply the hCG that is not bound to blood proteins. Most of the time it parallels fairly closely the total hCG results. Infact there are some advocates who have used this as well in first trimester screening (alhough there are some benefits of the free beta and that is the most widely accepted at this time). Successful IVF pregnancies do appear to be associated with slight elevations in hCG, but I am not sure how/if that is signficant enough to be factored into the final interpretation of the results. This may occur as a result of the intense hormonal stimulation often used to support IVF pregnancies early on that migh contribute to enhanced placental growth and, henice, enhanced hCG and sometimes PAPP-A as well. Also, it is unclear how much, if any, a vanishing twin would affect the results - again, probably not much. We are a long way off from an amnio, so please don't sweat that step right now. Recurrent pregnancy loss may increase your risk from an amnio, but it depends on the underlying cause of the RPL - I would again suspect, that increased risk would be relatively insignificant compared to the benefits of the procedure if it was truly indicated. Good luck, thanks for reading, and please let us know how things come along! Dr T
At Fri May 30, 08:51:00 AM 2008, anonymous said…

Dear Dr. T,
Thanks, I can see you sense my anxiety. I just received my results.
DS T 21- 1 in 627
T 13/18- 1 in 1447
I didn't get any specific values because I don't want to over analyze.Considering my age (38) I think these are pretty good. They are considered "negative". I am also still unsure of whether or not to do an amnio. The genetic counselor gave me several options. Should I go for the quad screen and get an integrated risk result or wait and just do the anatomy scan then make a decision. It just seems that 19 weeks for an amnio is kinda late. I know what we do if the diagnosis was abnormal. I'm just afraid without amnio something major like down syndrome could be missed.
Thanks again.
Anonymous from May 29th
At Fri May 30, 02:42:00 PM 2008, Anonymous said…

Dear Dr. T.

I'm carrying twins conceived through IVF using donor eggs. The donor is 26 at the time of donation. My NT results are 1.5mm and 1.6mm for the twins. I did not do a blood test as I was told with multiples the blood test can be inaccurate. Last week I had a level II ultrasound which shows the babies are normal in all aspects except 1 baby has a mild pelviectasis (measuring 4.1mm). My doctor said this is a soft marker for down syndrome but is commonly seen in normal baby boys so not to worry about it. The doctor also estimate the risk of down syndrome for the babies to be 1/3168 and 1/4752 based on NT test alone. Given that I had no blood test done and the mild pelviectasis, how much reliance can I place on the NT test alone? Would you recommend I forego an amnio at this point?

Thanks and I look forward to your response.

JT
At Fri May 30, 06:12:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous May 30: If you were one of my patients, I would suggest you stop with the testing right now (the numbers ARE great), have a MSAFP ONLY done at 16 weeks and a targeted ultrasound done at 18-20 weeks, mainly to look for birth defects that are NOT necessarily related to fetal chromosomal abnormalities. But, you have to make the decision that is right for YOU and if you cannot live without knowing for sure whether or not your baby has a chromosomal abnormality then you can alwasy choose to have an amniocentesis, regardless of what the risk/benefit ratio might be. Doctors cannot and should not make these decisions for you under the circumstances. Best of luck and let us know what you decide or how things turn out. Dr T
At Wed Jun 04, 06:25:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To JT: Although an NT measurement alone can only reduce your Down's risk by about 50%, your risk is SO LOW that I would completely ignore the pelvicaliectsis. Even if that double your risk (which it does not), the risk of Down syndrome would be so far below the risk of an amniocentesis, parrticularly with a hard-sought and twin pregnancy, I would not recommend it. You are at much greater risk for other complications such as cervical incompetence, preterm labor, preeclampsia, and gestational diabetes! Enjoy your pregnancy and best of luck! Dr T
At Thu Jun 05, 07:50:00 AM 2008, anonymous said…

Dear Dr. T,
We have decided to do the MSAFP and then the targeted ultrasound. Do you know what the detection rate for down syndrome is with the first trimester screening,MSAFP, and targeted ultrasound combined? I read that it could be 95%?
Thanks again
Anonymous May 30th
At Sat Jun 07, 07:12:00 AM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Jun5/May 30: The 95% detection rate is about right. If nothing is found on the ultrasound, your original risk based on the first trimester screen is reduced by at least 50%!
Dr T
At Sat Jun 07, 04:36:00 PM 2008, Anonymous said…

Dear Dr. T,

Thank you so much for the encouraging information. We have decided not to do amnio. Your blog is by far the most helpful website I have found. We are thankful for your service.

JT
At Sun Jun 08, 07:34:00 AM 2008, Anonymous said…

Dr. T,
Thank you for your blog!!!!!
I am confused about my ultra-screen results. The doctor told me that they were abnormal and the paper he gave me indicated "increased risk." He also told me that I shouldn't have even taken the test since I was planning an amnio. Does abnormal mean that my baby has down syndrome? I am 40 and this is my first pregnancy. He was very clear that the baby is abnormal.

NT: 2.7
CRL: 75.8
GA@U/S 13w3d
GA@draw 12w2d
hCG .65
PAAP .59 DELTA NT +0.96
Risk 1 in 135

Thank you for any information!
KC
At Wed Jun 11, 07:24:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To KC: The test is SIMPLY a screening test and your result indicates that you have a 1 in 135 risk for having a baby with Down syndrome. That is about half your 'age alone' risk in first trimester. Interpreted another way, you have a 134/135 chance that the baby does not have Down syndrome. Your options include, among others, 1) having an amnio; 2) having a genetic sonogram done at about 18 weeks and waiting to decide about the amnio until then, or; 3) doing nothing. The choice is yours, but the test result you have in hand does NOT say that your baby must be abnormal. Best wishes and let us know what you decide. Dr T
At Wed Jun 11, 07:27:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To JT: You are welcome and good luck for the rest of the pregnancy! Dr T
At Fri Jun 13, 04:16:00 PM 2008, Kristina said…

Thank you so very much for taking the time to respond. I have an amnio scheduled for the 27th.

-KC
At Sat Jun 14, 07:55:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To KC: Good luck. I am betting everything will be fine. Please let us know! Dr T
At Wed Jun 18, 06:29:00 PM 2008, Anonymous said…

Hi Dr. T. I have been reading your site/blog for two days now and it has been most educating. I am 34 yrs. old and did the first trimester screening at 12 weeks. I have gotten the results today and they told me that my risk for trisomy 21 is 1/69. This is my third pregnancy and my children were big births. My daughter (3 yrs.) was about 9 lbs. at birth and my son (2 yrs.) was 10.3 lbs. at birth. Becuase of this risk the next step (if I opt to do it) is the Amnio. My husband and I choose not to do the amnio with our other two pregnancies and are leaning towards not doing it with this one as well. The specialists did say that the NT was slighlty above normal and that my HCG levels were a bit high. I see that all these bloggers have their results and I will call in the morning to get mine faxed to me. I first assumed the NT measurement was on the bigger side because I have big kids and married to a 300 LB. ex-navy man. I am not a big person like my husband. This is all very new and emotional to me right now and will blog again once I get the accurate results. It is crazy to say I have been in the medical field all of my career but specialize only in Plastic/Cosmetic surgery. The unknowing is always out there and you learn new things every day. Thank you so much for your site and your Blog. Bless you. I'll keep in touch. RSM
At Thu Jun 19, 02:31:00 PM 2008, Anonymous said…

Hi. It is me again I posted on 6/18/08 - RSM. I have received my results and my husband and I opted not to do the amnio.
NT: 2.5mm
CRL: 64.6mm
GA@u/s: 12w5d
free beta hCG(mom): 1.50
PAPP-A MOM: 0.69
Delta NT: +0.88
From this at age 34 but possible 35 at due date. They are at the same time. I am 1 in 69 which is considered increased risk. Should I be very worried? My husband wants me to get a second opinion even if he pays for it is it worth it? To have a DS child is not really a bother to us. We will love and care for the same way as we do and have our other two. Let me know what you think! Thanks for the website again. RSM
At Thu Jun 19, 05:28:00 PM 2008, StacyTexas said…

Dear Dr. Trofatter:
I am 40 and pregnant with twins. My amnio showed one baby has downs, and one is normal. I am now 17 weeks. What is the risk of losing the normal baby if I have selective reduction of the downs baby? Is it higher or lower than continuing with both? They are in separate sacs with separate placentas. As you can imagine, this is a heart-breaking time.
At Sat Jun 21, 06:44:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To RSM: A 'second opinion" will simply tell you that your rsik for a Down's baby based on teh first trimester screen is 1 in1 69! To most, that is considered "high" but it depends on whether you look at the cup being 68/69 full or 169 empty! You might defer the decison regarding an amnio until you have had a good "genetic sonogram" done at 18-20 weeks. But, in the end you are the only one who can make the decision that is right for YOU and whether you need to know before delivery if your baby has Down syndrome. I wish you luck my friend and thanks for reading! Dr T
At Sat Jun 21, 06:51:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To StacyTexas: Selective reduction in midtrimester is fairly safe, but probably riskier than carying both babies. Below is an abstract form an article that adsresses this procedure in a large number of multiple gestations:

Efficacy of second-trimester selective termination for fetal abnormalities: international collaborative experience among the world's largest centers. (Evans MI, Goldberg JD, Dommergues M, Wapner RJ, Lynch L, Dock BS, Horenstein J, Golbus MS, Rodeck CH, Dumez Y, et al. Am J Obstet Gynecol. 1994;171:90-4)

OBJECTIVE: Our goal was to develop the most comprehensive database possible to counsel patients about selective termination for fetal abnormalities, because no one center has sufficient data to assess much more than crude loss rates. STUDY DESIGN: A total of 183 completed cases of selective termination from 9 centers in 4 countries were combined (169 twins, 11 triplets, 3 quadruplets). Variables included indications, methods, (potassium chloride, exsanguination, air embolus), gestational age at procedure, pregnancies lost (< or = 24 weeks), gestational age at delivery, and neonatal outcome. RESULTS: Indications for selective termination were 96 chromosomal, 76 structural, and 11 mendelian. Selective termination was technically successful in 100% of cases. In 23 of 183 (12.6%) miscarriage occurred before 24 weeks; 2 of 37 (5.4%) occurred when the procedure done at < or = 16 weeks and 21 of 146 (14.4%) when it was done thereafter. Air embolization had a higher loss rate: 10 of 24 (41.7%) compared with 13 of 156 (8.3%) by potassium chloride (chi 2 = 117, p < 0.0001). Three cases of selective termination performed in monochorionic pregnancies all resulted in pregnancy loss. Among 183 potentially viable deliveries, 7 occurred before 28 weeks, 19 at 29 to 32 weeks, 41 at 33 to 36 weeks, and 93 at > or = 37 weeks. Gestational age at delivery was not influenced by the technique used or the indication but was negatively correlated with gestational age at the time of selective termination. No coagulopathy or ischemic damage was observed in survivors. There was no maternal morbidity. CONCLUSIONS: (1) Selective termination in experienced hands for a dizygotic abnormal twin is safe and effective when done with potassium chloride. A total of 83.8% of viable deliveries occurred after 33 weeks and only 4.3% at 25 to 28 weeks. (2) Gestational age at the procedure correlated positively with loss rate and inversely with gestational age at delivery; this emphasizes the need for early diagnosis in multifetal pregnancies. (3) Coagulopathy tests are probably unnecessary.

Best of luck Stacy, and please let us know how things turn out. Dr T
At Thu Jun 26, 09:31:00 AM 2008, Trini said…

dear Doctor T,
I would really appreciate your comments on my screening test. They have been done in Spain so maybe some words are different.
I am 39, caucasian, this is my first pregnancy, and in good health. My husband is 25 (I heard his age counts too). For my age I am keen to do an amnio, but just for reassurance, I would appreciate your interpreatation.

test has been run at 11w6d
PAPP-A 2,17 mUI/ml
MOM 1,04
NT 0,9 mm
Beta Hcg 18,6 mUI/ml
they give me an overall risk of 1/1960 (I have noticed it is differenciated for each abnormality in the other posts), while in theory mine should be 1/98, although data seam good, I can't find any chart explaining the right levels for each of the other values.
Please help.

Thank you,

Trinidad
At Thu Jun 26, 09:36:00 AM 2008, Trini said…

Dear doctor T,
I have another question, how important is the doctor's experience in performing the amnio? is the risk reduced by experience?
thank you.
At Thu Jun 26, 02:02:00 PM 2008, Anonymous said…

Dear Dr T.

I just recently recieved the actual results of my 1st trimester screening. This is very sensitive subject for me since my 1st son was born with trisomy 21 at age 26. Both me and the father were tested with normal keryotype. I had a second child who was completlely healthy. This pregnancy i opted for the 1st trimester screening and results were as followed.

Age at term: 31.2
Race: white
down syndrome HX: yes
weight: 255lbs
IDDM: no

NT 1.47 MoM
Nt: 2.2mm
Gest Age: 12.1 wks
CRL: 5.8cm

PAPP-A : 2.23 MoM
Hcg: 2.79 MoM

I was given a screening risk of 1:105 for trisomy 21 and 1: 10,000 for trisomy 18. Nasal Bone was present and i was told that the nuchal thickness was within normal range. My due date was based on 1st ultrasound at 6 weeks due to irregular periods. I was 11w 6 days when u/s was preformed.

My question is what does my prior history of trisomy 21 affect my results. It says it was used in risk assessment, but iam not sure if my lab values were off as well. I declined an amnio due to failed attempt. Opted for level II genetic u/s which showed everything as should be and know markers. Baby also measured 4 days ahead. Thanks so much for taking the time to help me understand these test. I feel alot more at ease since the u/s was normal, but i know its not 100%

Thank you
Cindy
At Thu Jun 26, 07:37:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Trini June 26: The results are wonderful. The strength of the test is in the COMBINATION of the results, not the individual values. You will go crazy if you try to interpret each of those on your own! I would not recommend an amnio under these circumstances, but that choice is entirely yours. Like any invasive procedure, the risks are somewhat related to not only the skill, but the experience of the operator. The more and the more skillful, the lower the risks. Best wishes! Dr T
At Thu Jun 26, 07:41:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Cindy: Having a previous child with a chromosomal abnormality may increase your risk (our genetic counselors quote 1%), although I have no idea how they factor that into the equations and computer database used to calculate your combined risk assessment. The normal ultrasound should reduce your risk at least another 60-80%, so odds are, your baby is just fine! Best wishes and let us know how things turn out. Dr T
At Fri Jun 27, 06:53:00 AM 2008, Anonymous said…

Hi: How reliable in FTS in twins pregnancy? I was told it is not and some said it is. We are trying to make a decision if we will pursue CVS. I am 36. I would be 1 month away from 37 when it is a due date (due date 1/12/09). I am now 11 weeks almost 12. I did the FTS, the ultrasound looks good. The genetic counselor said the blood test will not be as accurate as in singleton pregnancy. The spaces on the necks are normal and looks good. We are conceived using IVF (1st cycle). It is unexplained infertility. I had natural preganancy once but miscariage during 7-8 weeks (no heart beat detected). No family history of birth defect on both side. I am asian if this is matter and my husband is white (British/ French). I really appreciate your opinion. Thank you.
At Fri Jun 27, 10:03:00 AM 2008, Anonymous said…

Dr T,

Thanks so much for your reply. I do have one more question. I noticed boy my papp-a and Hcg were both sorta high. In cases of down syddrome Isnt the PAPP-A typically low? I have tried to find a normal range for these hormones at 12 weeks so i really do not know which of mine are too high or to low because the final results do not indicate. Could you please let me know if both those hormones are abnormal or either or just one? Sorry to bother you again. I just cant seem to find anything showing normal results for these so i have no clue if mine are too high or two low? thanks so much and you help so many people. God Bless

Thanks Again
Cindy
At Fri Jun 27, 12:34:00 PM 2008, Anonymous said…

Hello,
I'm 12 weeks and 6 days and had a NT done two days ago.. I'll be 38 years old when this baby is born.. The results were very bad due to the lack of nasal bone... my risk factor is 1/20 for Down syndrome. I have read all through your blogs and don't see anyone else with this problem... I'm very scared now and wish I would have not had the test.. how common is it for a nasal bone to develope slow? I have two other healthy children. The neck fluid was fine though.. any infomoration you can provide would be very much appreaciated... i'm very panicked. thank you.
At Tue Jul 01, 01:05:00 PM 2008, Anonymous said…

Dr. T.
I left comment earlier on 6/27 about reliable in FTS in twin. I just got a test result for FTS.
IVF/ICIS cylce
36 yrs (asian) weight 165 lbs
Gest Age: 11.3 wks
IDDM: no DS HX: NO
NT: 1.3 mm and 1.5 mm
CRL: 49.3mm and 48.3 mm
Nuchal Translucency: 1.08 MoM/ 1.25 Mom
Papp- 3.00 MoM
Hcg - 1.36 Mom

Down Syndrome: Screening Risk 1:660 Age Risk 1:130
Risk Cutoff: 1:50
Trisomy18: Screenind Risk - can't accurately estimated in twin
Age Risk 1:470
Risk Cutoff: 1:100

We were going to go for CVS this week, but unfortunately, there is a mix up in insurance and doctor office. So I couldn't see one of the best Dr in CVS in Chicago. So we opt not to increase risk by doing CVS with anthor doctor that may not frequently do CVS on twins. We were told by genetic counselor and another DR who does CVS that our position is good base on FTS result.

We would do Amnio in 16 weeks, but if there would be an unfortunate result, would that be too late to do selective reduction which it could be 18 weeks by the time we get the result?
I would appreciate any comment on your expert. These tests are very confusing and driving us crazy. Thank you so much for having such an informative blogg for all Mom-to-be.

W.
At Tue Jul 01, 05:51:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To W: Those are very good first trimester results. I would suggest an MSAFP only (and perhaps another ultrasound) at 16 weeks and then a good genetic sonogram at 18-20 weeks. If all that checks out fine, you probably do not need to have any invasive procedure done and with those first screening results, we would not ordinarily recommend a CVS at all. Of course, regardless of what we suggest, the final choice is yours! Best of luck and please let us know how things turn out. By the way, at the time of the genetic sonogram, ask your doctors to evaluate your cervical length as well! Infertility patients are notorious for having unsuspected cervical incompetence. Dr T
At Tue Jul 01, 05:54:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To W again: It is not to late to do selective reduction at 18 weeeks or even later, but the risks do go up with gestational age. If you have an amnio done and you are seriously considering selective reduction if one of the babies is chromosomally abnormal, consider having a FISH study done from which you can get a result back in about 72 hours. I am NOT recommending it, but that is an option to consider if you elect to proceed with the amnio. Dr T
At Wed Jul 02, 11:35:00 PM 2008, Anonymous said…

Out of curiosity, when you mention race being one of the factors taken into consideration, how does that play out? Are you (when combined with the other factors) at a higher risk for an abnormality if you are African American or asian than you are if you're caucasian, etc? Thanks.
At Thu Jul 03, 09:54:00 AM 2008, Anonymous said…

Saranenko: I am writing from Kyrgyzstan and really need your help, as I can’t get any definite answer from my doctors here and I am really worried. I am 29 years old, this is my first pregnancy. I am Caucasian and my husband is Asian. At 12 weeks of pregnancy NT was measured – 4 mm. I am now 30 weeks pregnant and have just discovered that the norm is considered no more than 3 mm. Neither the ultrasound specialist nor my doctor have sent me for any additional screening tests at that point. I have done only the ultrasounds on week 18, 23 and 28 with Doppler which stated that all results are normal. Does it mean that there is nothing to worry about considering the latest ultrasound results, or only early screening tests could identify that? Thank you so much in advance!
At Thu Jul 03, 02:46:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous July 2: Ethnicity does not increase risk for certain abnormalities, but it does factor in to what is considered 'normal' ranges for the maternal serum markers in first trimester. below is an abstract from an article that makes this point:

Maternal weight and ethnic adjustment within a first-trimester Down syndrome and trisomy 18 screening program. Krantz, et al., Prenat Diagn 2005;25:635-40.

OBJECTIVE(S): To estimate weight and ethnic group correction factors for first-trimester screening markers. METHODS: Ethnic-specific median MoM free beta hCG and pregnancy associated plasma protein A (PAPP-A) and delta nuchal translucency values were calculated for cohorts of maternal weight (20 lb each) using data from 51,206 patients undergoing first-trimester screening. False-positive rates for Down syndrome and trisomy 18 were evaluated both prior to and after weight and ethnicity adjustment. RESULTS: Free beta hCG and PAPP-A significantly decreased with increasing maternal weight while nuchal translucency increased by a clinically insignificant amount. For free beta hCG the regression formula indicated that after accounting for maternal weight MoM values were 16% higher for African Americans, 6% higher for Asians and 9% lower for Hispanics compared to Caucasians (p < 0.001, p = 0.001, p < 0.001, respectively) but there was no significant difference for Asian Indians. For PAPP-A, MoM values were 35% higher for African Americans (p < 0.001) but were not significantly different for the other ethnic groups compared to Caucasians. Down syndrome false-positive rates did not vary with maternal weight prior to (p = 0.291) or after weight adjustment of biochemistry (p = 0.054). Trisomy 18 false-positive rates varied significantly with weight both before (OR = 1.455 per 20-pound increase, p < 0.001) and after (OR = 1.066 per 20-pound increase, p = 0.01) weight adjustment of biochemistry; however, the odds ratio was greatly reduced after weight adjustment. CONCLUSION(S): The first-trimester screening markers, free beta hCG, PAPP-A and nuchal translucency vary with maternal weight and ethnicity. Adjustment of free beta hCG and PAPP-A is indicated but adjustment of nuchal translucency results may not be necessary. Copyright 2005 John Wiley & Sons, Ltd.
At Thu Jul 03, 02:51:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Jul 3: Presuming the nuchal translucency measurement in first trimester was accurate, the baby could still have a structural or chromosomal abnormality that has not yet been detected. The normal ultrasounds since then are reassuring (and probably indicate that the first trimester scan may not have been accurate), but at this point my only recommendation would be for your doctors to carefully evaluate the baby after delivery. There does not appear to be a reason to do an amniocentesis to check the baby's chromosomes at this time being so far along in the pregnancy and no abnormalities seen by ultrasound. Best of luck and let us know how things turn out. Dr T
At Thu Jul 03, 07:59:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous June 27: Sorry, I missed your comment before today. Not everyone who does first trimester screening is "certified" to perform nasal bone assessment. It can be difficult and in the U.S. many laboratories do not make the effort. As the recent abstract below indicates, including the nasal bone in the first trimester screen may not increase the detection rate of Down syndrome, but it does help reduce the "false positive rate." In other words, if the nasal bone is present, the baby is less likely to have a "positive screen" under circumstances in which the baby really does not have Down syndrome. I am curious to know what were the results of the other components of your first trimester screen. Best regards and please let us know what you find out.
Dr T

Has, et al., Fetal Nasal Bone Assessment in First Trimester Down Syndrome Screening. Fetal Diagn Ther 2008;24:61-66. Objective: To evaluate the contribution of nasal bone assessment in the first trimester Down syndrome screening. Methods: The fetuses which underwent first trimester screening with nuchal translucency (NT) measurement were evaluated for the absence or presence of nasal bone according to the instructions described by the Fetal Medicine Foundation, London. Results: Among the 1,807 fetuses included in the study, 9 had trisomy 21. The detection rate of Down syndrome with NT measurement was 77.8% (7/9) with a false-positive rate of 4.5%. Incorporation of biochemical tests (PAPP-A, and free beta-hCG measurement) into the screening increased the detection rate to 88.9% (8/9) and decreased the false-positive rate to 3.6%. The prevalence of absent nasal bone was 7/1,798 (0.39%) in chromosomally normal fetuses, and 3/9 (33.3%) in Down syndrome fetuses. Sensitivity, specificity, positive predictive and negative predictive values of absence of nasal bone for trisomy 21 are 33.3% (CI: 0.12-0.64), 99.6% (CI: 0.99-0.99), 30% (95% CI: 0.11-0.53) and 99.7% (95% CI: 0.99-0.99), respectively. The positive likelihood ratio of absent nasal bone was 85.6 (95% CI: 26.2-279.5), and the negative likelihood was 0.67 (95% CI: 0.42-1.06). When nasal bone assessment was incorporated into the NT risk assessment or combined test, the detection rate of trisomy 21 was not changed, however, the false-positive rate decreased to 3.4 and 3%, respectively. Conclusion: The absence of fetal nasal bone has a high positive likelihood ratio for Down syndrome in the first trimester screening, and the presence of nasal bone may potentially lower the need for invasive testing. Copyright © 2008 S. Karger AG, Basel.
At Thu Jul 03, 08:40:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous June 27: Personally I have found combined first trimester screening (NT measurements plus maternal serum markers) to be very helpful in twins. Below is an abstract from a recent article that gives you some idea of its value. Thanks for reading and good luck to you for the rest of the pregnancy! Dr T

Chasen, et al., First-trimester risk assessment for trisomies 21 and 18 in twin pregnancy.Am J Obstet Gynecol 2007;197:374.e1-3.

OBJECTIVE: Our objective was to describe performance of first-trimester combined risk assessment in twin pregnancies. STUDY DESIGN: Twin pregnancies that underwent risk assessment in our ultrasound unit from 2003-2006 were included. Adjusted risks for trisomies 21 and 18 that were based on age, nuchal translucency (NT), and biochemistry were provided for each twin. Detection rates for Down syndrome and trisomy 18 were calculated for age/NT, and age/NT/biochemistry at a screen-positive rate of 5% of pregnancies. RESULTS: Five hundred thirty-five pregnancies were included. Median maternal age was 34 years, with 47% of women > or = 35 years old. There were 7 fetuses in 6 dichorionic pregnancies with Down syndrome and 3 fetuses in 3 pregnancies with trisomy 18. For a 5% false-positive rate, age/NT identified 83.3% of Down syndrome and 66.7% of Trisomy 18 pregnancies. Adding biochemistry resulted in 100% detection rates for both conditions. CONCLUSION: The addition of biochemistry may enhance first-trimester risk assessment in twin pregnancies. Further studies with larger numbers of affected pregnancies are needed.
At Mon Jul 21, 10:03:00 AM 2008, Anonymous said…

Hello,

I posted a repeat question on the 27th Of june, but I think you may have overlooked it.. I appriciate this Blog its full of great information. My results were as followed and i Do have a previous son with trisomy 21 (both parents normal kerotype)

Of course my results came back 1 in 105 for DS with my previous ds pregnancy calculated into my risk. I was really wondering what in my blood work etc. from the screening would also indicate an increased risk for downs.

Age at term: 31.2
Race: white
down syndrome HX: yes
weight: 255lbs
IDDM: no

NT 1.47 MoM
Nt: 2.2mm
Gest Age: 12.1 wks
CRL: 5.8cm

PAPP-A : 2.23 MoM
Hcg: 2.79 MoM

I know that my HCG is increased, but itsnt my PAPP-A also increased? I thought that a low pappa and high hcg was an indication? I have tried to find the normal ranges for these two hormones online for my weeks gestation, but havent had any luck. Could you tell me which one or if both are out of normal range? thanks you so much for your help. BTW I did have a normal level II genetic u/s and have fetal echo tomorrow.

Thanks a bunch
Cindy
At Tue Jul 22, 06:23:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Cindy: You are correct. The classic combination that goes along with Down syndrome is an elevated hCG and a low PAPP-A. In your case, both values are greater than the 95th percentile! I think the previous Down's baby and the NT measurement which is at about the 90th percentile probably are driving your risk. But, I am betting right now that this baby is okay! Please let us know how things turn out. Dr T
At Thu Jul 24, 04:40:00 AM 2008, Anonymous said…

Dear Dr,
I have just done my first trimester screening at 13 wks, and my results are as below, I am so worried with the results, because my doctor asked me to do the amino test, but I have doubts about it due to the risk. Hope you can clarify my results for me :
Maternal age : 28 yrs
Race : Asian
Maternal age related risk for T21 = 1:789
Adjusted risk for Trisomy 21 = 1:194
Maternal age risk for T13/18 = 1:1525
Adjusted risk for T13/18 = 1:25800
CRL : 74.8mm
Nuchal trnaslucency : 2.10mm
Free Beta-hCG : 104.300IU/1 2.9746MoM
PAPP-A : 2.370IU/1 0.5779MoM
Thank you so much for your help
At Fri Jul 25, 06:28:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous July 24: The relatively high hCG level compared to the low PAPP-A level is driving your risk. You ca choose to have the amnio or you can wait to have a level 2 ultrasound done at 18-20 weeks. If that is 'normal', your risk for Down syndrome will be reduced at least another 50%. However, if it is abnormal in some way, you will have delayed the diagnosis by putting off the amnio. It all depends on YOUR need to know, weihing the risks and the benefits of the amnio, not what your doctor wants you to do. The final choice is yours. Best wishes and please let us know. Dr T
At Fri Aug 01, 10:26:00 AM 2008, Anonymous said…

Thank you for your efforts Dr. Trofatter. Your posts are very informative. I just had my 1st trimester screen with the following reassuring results:
Free Beta hCG MOM: .33
PAPP-A MOM: .55
NT(mm): 1.5

Downs Syndrome risk before screening: 1/276 risk after screening: 1/5501
Trisomy 18/13 risk before screening: 1/507 risk after screening: 1/757

This is my 8th pregnancy and I have two children (boys). I have had 4 miscarriages and 1 little girl born at 28 weeks with severe symmetric IUGR (chromosomally normal). She died at 3 months. My last pregnancy (successful with my son) was through IVF and this one was as well. I am positive for Factor V and MTHFR (hetero on both) and am taking lovenox and low dose aspirin. My concern with this pregnancy is the low HCG level. My level was listed at the 2nd percentile. Does that put me at increased risk for other problems such as IUGR? I had my estrogen, progesterone and HCG monitored about every 4 days from 14 dpt to about 11 weeks and my HCG seemed to peak at 8 weeks (going down slightly) and then really began to drop off around 9.5 to 10 weeks.

Also, my risk for Trisomy 18/13 didn't come down much from my age related risk due to the low hormone levels. We did PGD this time for X,Y, and 18 so I'm guessing this reduces my risk in the 18/13 category since they are combined. The genetic counsellor couldn't really put the decrease in perspective for me.

My stats: I'm 35 (today) and have no health problems. I did have a congenital heart defect that was previously repaired.
At Thu Aug 07, 06:35:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Aug 1: If anything, the more likely reason is slow or poor early development of the placenta. You may be at increased risk for an IUGR baby again, but I am sure you will be carefully monitored for that by growh and Doppler flow studies. Best of luck and please keep us informed as to your progress! Dr T
At Sat Aug 09, 05:11:00 AM 2008, Anonymous said…

Dear Dr. Thank you very much for having this blog!

I’m 34 years old, White (Venezuelan/ Spanish mixed) and my husband white British
55 kg BMI 1

Results

11 weeks + 6
CRL 50.7 mm
NT: 2.7 mm
Free beta Hcg: 21.770 IU/I, equivalent to 0.4236 MoM
PAPP-A: 1.960 IU/I, equivalent to 0.8184 MoM

Background risk: 1:303 (T21) 1:529 (T13/18)
Ultrasound risk: 1:32 (T21) 1:177 (T13/18)
Biochemistry risk: 1:2152 (T21) 1: 2214 (T13/18)

Adjusted risk: 1:224 (T21) 1:561 (T13/18)

They didn’t check for the nasal bone and we found out later that he wasn’t certificated to do it.

We are thinking to go for a 2nd Scan/opinion in another place (with nasal bone check) but is not going to be until 13 weeks and 4 days. Is that too late?. We really won’t want to have an invasive test as this baby is so precious and the risks of miscarriage and complications. We have been trying for 5 years (1 miscarriage) and we are currently on a waiting list for IVF. Sorry about the long post and thank you very much for your help about this results.
At Wed Aug 13, 06:31:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Aug 9: A risk of 1 in 224 is fairly good for a first trimester screen and I like your combination of serum markers - especially the normal PAPP-A. You have less than a 0.5% risk the baby has Down syndrome! Many patients will simply opt to have a level 2 (targeted or genetic) sonogram done at 18-20 weeks under these circumstances and not risk any invasive study unless there are significant findings at that point. Odds are that this baby is chromosomally normal. Best wishes and let us know how things turn out. Dr T
At Thu Aug 28, 05:16:00 AM 2008, Wendy said…

I just thought I'd post an update. I originally posted on August 1 with reassuring 1st trimester screening results but an abnormally low HCG level (2nd percentile). I had a 28 week preterm girl with severe IUGR who passed away at 3 months and I've had 4 1st trimester miscarriages and I have two live children. Unfortunately this past weeked my baby died unexpectedly at 16 weeks. Ultrasound confirmed no heartbeat (I went to ER because I couldn't hear her with the doppler). She measured 16 weeks to the day. I had just had a great OB appointment on Wednesday and heard her with the doppler Thursday evening with a heart rate of 155. Friday night I couldn't find her and it was confirmed that night. We have no idea what to think and are awaiting many test results. I certainly don't want to scare anyone because this is obviously the statistical anomaly. I just wanted to update you on the situation. Any thoughts, comments would be welcome.
At Wed Sep 03, 05:54:00 AM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Wendy: I am so sorry for your loss, but I appreciate the information. Did they happen to do any chromosomal or pathologic evaluation of the baby and/or placenta. I am wondering if chromosomal mosaicism might have contributed to the unusual hCG results. We are ALL here to learn and if you find out anything else, I would certainly appreciate hearing from you again. Kind regards, Dr T
At Thu Sep 04, 05:45:00 AM 2008, Wendy said…

Thanks so much for responding Dr. Trofatter. Our little girl went to Childrens Hospital of Philadelphia for autopsy and chromosome analysis on her and on the placenta. I have the preliminary results of the autopsy and the pathologist seems to think it was related to a vascular problem. They noted subtle abnormalities in some of the fingers that to them appeared to be the result of some type of vascular disruption. The placenta was unusually small and she was actually about a week behind at 2.1 ounces. There was some evidence of a placental abruption/separation. Interestingly enough our other daughter who had severe symmetric IUGR was missing her right forearm and extensive testing was done with her. She was chromosomally normal and no known genetic syndrome fit. The placenta was also very small with her. They felt it was due to a vascular disruption. Many tests are pending but I'm afraid we're not going to find anything else. I suppose it would be unlikely that chromosomal mosacism would manifest in the same way twice. That would be really bad luck... I'm interested to see if there is chromosomal mosacism of the placenta but my intuition tells me no. I keep asking if there could be a strange genetic syndrome with only girls but everyone keeps saying that's not likely. I have a combined thrombophilia but this time I was treated with low dose aspirin and lovenox. I'm scared and not sure where to go from here.
Thanks for the interest - Wendy
At Thu Sep 04, 09:46:00 AM 2008, Anonymous said…

Dear Dr T.

Thank you for great info, really the only good info site I have found.

My data: 32 years, caucasian,non-smoker, weight 80kg, BMI 26. First child. Pregnant 12weeks and 3 days.

I had the first trimester screening 3 days ago, so at 12 weeks. My results are the following:
fb-hcg 127 ng/ml - 2.90 MoM
PAPP-A 1.82 mlU/ml - 0.82 Mom
CRL 55mm
NT 2 mm - 1.37
Nasal bone was not checked

Risk for Downs:
Biochem. risk + NT 1:201
Double test: 1:184
Age risk: 1:619

Based on the risk 1:201 the doctor recommends amniocentesis. Do you agree? An is there I high risk for DS. Afer what I understand only the HCG level is increased, the other are normal?
Just looked through other questions on this page and find the other have almost the same results than me but different risk.
They did not take my weight into account, can that give a wrong result?

And I saw another on this site with the following:PAPP-a 1.81 mlU/ml 1.29 MoM. Why is the calculate MoM so different from mine when the Papp-a is almost the same?

Thank you for your time.
At Sun Sep 07, 10:12:00 PM 2008, Anonymous said…

My best friend had a NT of 3 mm at first ultra sound. CVS test was done a week later & NT was 5 mm. She is awaiting results & is an absolute mess. She is a healthy 34 year old with a healthy 18 month old baby and no other pregnancy issues. Is there anything I can say or research that may shed light on the situation of why & what it means that she jumped 2 mm in a week's time... whether it be positive or negative while she waits for the CVS results. Also how bad is a 5? Any info would be appreciated. Thank You.
At Tue Sep 09, 06:03:00 PM 2008, Anonymous said…

Hi I'm now almost 16 weeks pregnant. 1st trimester screening was reviewed with us today. My beta HCG was extremely high MoM was 10.something. The rest of numbers and NT were not indictative of downs. I did have some bleeding and a small subchorionic bleed around the time the blood tests were done. My risk of downs is 1 in 230. I will be 39.3 at expected due date. We will do amnio in a few days and larger placental blood profile too. Sorry I don't have exact numbers but I know the greatest and really only real odd result was the extremely high beta HCG. Any thoughts on what it means?
At Thu Sep 11, 08:40:00 AM 2008, Vicki said…

Dear Dr Trofatter,
I am a British woman of 37yrs and pregnant with our 5th child (i have never miscarried, all full term babies). I have recently received my results for my blood screening. I have had them done in Spain and I am completely confused at the terminology used. I have read all 85 of the comments on your page (and although helpful in many ways) can find nothing which allows me to understand my results. I would really appreciate some clarity.

My results read as follows
Gestation 12wks
Beta HCG 126ngr/ml(i dont understand the ngr as all others i have read do not use these measurments)
PAPPA 1.39 mU/ml
CRL 58mm
NT 1.6mm
LA(i dont know what that is!)Normal

I have booked to have an amnio at 15weeks even though my gynae said she found the ultrasound normal and contradictory to my hcg levels.
I also wondered whether it was advisable to have another blood screening as although it was thought i was 12 weeks at the time of the test I was in fact just under 11 weeks. Would this affect the results which I was given as a risk factor of 1/250 chance of downs syndrome?

I would like to thank you in advance for the help you offer to all of us fragile expectant mothers.
Vicki
At Mon Sep 15, 05:35:00 PM 2008, Anonymous said…

hello I am very worried about down syndrome because of a "possible shortened nasal bone" is how the radiologist put it on my 18 wk fetal anatomy scan. Nothing else was found. My AFP was normal and when I got my first trimester screening my results were 1/10000. The perinatologist office assured me that when I got the nuchal scan the nasal bone was fine. I guess my question is do I have anything to be worried about. They will rescan me for nasal bone measurements. I also read it could mean cleft lip?
At Wed Sep 17, 08:27:00 PM 2008, Anonymous said…

I just had my First Trimester Screening today and like many others, I'm very confused on what all the numbers mean. I'm 35 years old and at the time of delivery I will be 36. This is also my first pregnancy.
NT (mm) 2.7
CRL (mm) 61.3
GA 12w3d
Free Beta hCG (MOM) 0.86
PAPP-A MOM 1.04
Delta NT +1.13
risk-
down syndrome 1 in 272
trisomy 18/13 1 in 4,812
Looking at the charts I can plainly see the risk for down syndrome and have planned on having an Amniocenteis. But could you please explain to me what part of the screening raises red flags for down syndrome?
Thank you and I'm anxiously awaiting your response!
At Thu Sep 18, 08:25:00 AM 2008, Anonymous said…

Hi Dr. T,

just had my results from the Ultrascreen.
My report shows:
NT(mm):1.1
CRL (mm): 54.5
Free Beta hcg (MOM): 1.73
Percentiles: 80
Papp-A MOM: 0.38
Delta NT: -0.33

RESULT: Down syndrome after screening 1 in 19--Increased risk
Trisomy 18/13: 1 in 1,541--within range.
AGE: 42 yrs.old
Ethnicity: Hispanic
Weight: 125 lbs

I've already sheduled a CVS for next week but if you can help me with what I'm looking at. The baby looks sooooo healthly - great heart and organs (so they said) looked good. Baby was moving, kicking and I've been feeling so great (up until now that is). Thanks, Maria
At Fri Sep 19, 03:35:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Vicki: Based on what you ahve given me, I cannot interpret the results either. The values need to be expressed in terms of multiples of the median (MoM). The nuchal translucency (NT) measurement is reassuring. I am not sure what "LA" means - perhaps it is the nomeclature they use for nasal bone and if that is "normal" and present, then that is also reassuring. Regardless, your composite risk of 1 in 250 is actually quite good. At your age of 37, the first trimester risk for having a baby with Down syndrome is about 1 in 133 and the risk of all fetal chromosomal abnormalities is about 1 in 66. So your results are about half your 'age alone' risk for Down syndrome. Although that still puts you in an 'at risk' or 'screen positive' range because the cutoff is often set at 1 in 270, the odds are that your baby is chromosomally NORMAL. Many women in the U.S. will not opt for an amniocentesis in your situation but simply have a 'genetic sonogram' done at 18-20 weeks before making their final decision regarding an amnio. I hope this helps a little. Best wishes and let us know how things turn out. Dr T
At Fri Sep 19, 03:37:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 15: Listen to your Perinatologist. With those first trimester screening results and the presence of the nasal bone in first trimester, the overwhelming odds are that your baby does not have Down syndrome. Good luck for the rest of your pregnancy! Dr T
At Fri Sep 19, 03:40:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 17: Your age and the relatively wide nuchal translucency measurement are driving your risk. THE ODDS ARE STILL VERY MUCH IN YOUR FAVOR THAT THE BABY IS CHROMOSOMALLY NORMAL. In fact the serum markers are VERY reassuring. Good luck and let us know how things turn out. Dr T
At Fri Sep 19, 03:45:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

Maria: Your age and the big differenc between the hCG and the PAPP-A MoMs are driving your risk. The NT measurement is very reassuring, but unfortunately, NT alone will only help us pick up about half of the babies with Down syndrome in first trimester. Even babies with Down syndrome can look "perfectly normal" at this point, so the choice to have the CVS is probably a wise one. We wish you the best and please let us know what you find out. Dr T
At Fri Sep 19, 08:03:00 PM 2008, Anonymous said…

Hi, I am having twins and heard that first trimester screening is not that accurate so would like to get some interpretations of the findings. I am 36.
Baby A:
NT(mm): 1.8
CRL(mm): 71.8
GA @ U/S: 13w1d
GA @ Draw: 12w2d (not sure what this is)
Free Beta hCG (MOM): 0.78, percentiles 40
PAPP-A MOM: 1.30, percentiles 60
Delta NT: + 0.09

Baby B:
NT(mm): 1.6
CRL(mm): 70.1
GA @ U/S: 13w1d
GA @ Draw: 12w2d (not sure what this is)
Free Beta hCG (MOM): 0.78, percentiles 40
PAPP-A MOM: 1.30, percentiles 60
Delta NT: - 0.09

Are these numbers looking good? Also should I trust interpretation of this screening given the blood test for twins are not reliable.

Thanks - Mimi
At Sat Sep 20, 12:20:00 PM 2008, Lara said…

Dear Dr T,

Very concerned about NT results. At 12w1d, baby measured 54 mm (CRL) and NT measurement was 3.7mm. No bloods were run as there is a second gestational sac. This was an ivf pregnancy with embryos frozen at age 38(barely). The perinatologist thinks the "most likely" possibility is that the baby (who looks fine in all other respects) was exposed to an infection of some sort and is now in a recovery phase. I ran this theory past another perinatologist and she was puzzled. We are going to have an amnio at 16 wks. I have had 2 miscarriages in the past (insufficient tissue for chrom testing). The question is: have you ever heard of an "infection" being the reason for an enhanced NT? thank you,

Lara
At Sun Sep 21, 05:26:00 AM 2008, Anonymous said…

Hi Doctor. Please can you advise. I have completed the blood test at 12w 2d. I am 34 but will be 35 by the time I deliver. The combined test result was positive, but my papp-count was 0.56 (very low). I had a kidney infection in early pregnancy and down syndrome runs in my husband's family. I am very concerned about placenta insufficiency and low growth, as my baby has always been a week behind gestational age.
At Sun Sep 21, 04:20:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 4: I apologize for the delay in answering, but I JUST got your comment delivered to my mailbox today. Your risk is being driven by the wide difference between the MoMs for the hCG and the PAPP-A, although the latter is "normal." We would certainly offer you an amniocentesis but the choice is yours whether or not you have it done. Many women with your composite result will simply wait to have a 'targeted ultrasound' done at 16-20 weeks and then decide about the amnio based on those results. A reassuring ultrasound at that point reduces your risk for Down syndrome by at least 50%. Good luck and let us know how things turn out! Dr T
At Sun Sep 21, 04:26:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 9: Pardon the delay in answering, but I JUST got your comment delivered to my mailbox today. At age 39, your first trimester risk for Down syndrome (based on age alone) is 1 in 75. So despite the "high hCG" results (whatever that might be), your composite risk assessment of 1 in 230 is actually VERY good. Indeed, many women in your situation will simply opt for a
'targeted ultrasound' at 18-20 weeks before making a final decision regarding an amnio. If that is normal, your risk is reduced at least another 50%. Let us know how things turn out! Best wishes. Dr T
At Tue Sep 23, 07:23:00 AM 2008, Anonymous said…

Dear Doctor T
I am 12 weeks and I had an NT scan at 11 weeks plus. The results showed an elevated NT of 2.8mm and the presence of a nasal bone. The risk assessment was 1:51 of T21. The doctor has not recommended bloodwork and has suggested an amnio at 15 weeks to check for chromosomal abnormality. Obv my partner and I are very worried - how accurate is this test - the sonographer said that only 3% of babies are misdiagnosed by this test which seems at odds with my risk of 2% for Downs. Also the sonographer repeated the measurements a few days later and found measurements of 2.0mm but was not entirely satisfied as the baby was not very cooperative at that point. How worried should I be? And is it worth repeating the test by a different ultrasound operator in case there has been an inaccurate reading? Please help!
At Tue Sep 23, 08:28:00 AM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 7: With an NT measurement of 5 mm, there is more than a 50% chance the baby has a chromosomal abnormality. In addition the baby is a very high risk for a syndromic (genetic) problem or a major cardiac malformation. We usually recommend genetic testing by CVS or amniocnetesis based on the NT measurement alone at this point. Wish her the best. Dr T
At Wed Sep 24, 02:47:00 AM 2008, Anonymous said…

hi. I was the anonymous writer on sept. 15 that was worried about a possible shortened nasal bone. I went back to the perinatologist and they measured the nasal bone and said at my gestation(21 weeks) anything under 5 is considered short. My baby's was 6.7. So totally normal. I just wanted to update anyone who might be reading and worried one day in the future. There is not much on the Internet about it. Also I know a lady who tested 1:5 for downs and got an amnio back which said normal healthy baby. So dont give up hope everyone. Good luck to all. Thank u doc for answering so quick. It was reassuring.
At Thu Sep 25, 11:40:00 PM 2008, Anonymous said…

Hi Dr. T,
I am pregnant with twins and just did the first trimester screening. I've heard that this may not be accurate for twins so want to hear your assessment.
BabyA: CRL 71.8mm, NT 1.8mm, GA@U/S: 13w1d GA @ Draw 12w2d (CRL), Free Beta hCG (MOM):0.78 (40 percentile), PAPP-A MOM: 1.30 (60 percentile), Delta NT: +0.09
Down Syndrome Risk: before screening: 1/211, after: 1/4201
Trisomy 18/13 risk: before screening: 1/397, after: 1/7921

BabyB: CRL 70.1mm, NT 1.6mm, GA@U/S: 13w1d GA @ Draw 12w2d (CRL), Free Beta hCG (MOM):0.78 (40 percentile), PAPP-A MOM: 1.30 (60 percentile), Delta NT: +0.09
Down Syndrome Risk: before screening: 1/211, after: 1/4201
Trisomy 18/13 risk: before screening: 1/397, after: 1/7921

Since this test (or the second trimester blood test) may not be accurate, I am debating whether to do amnio or not. However, I've heard that the miscarriage rate of amnio is much higher for twins. What do you suggest?

Thanks - May
At Tue Sep 30, 01:02:00 AM 2008, Anonymous said…

Dear Dr T.
Thank you for the answer, I wrote you originally on September 4th.
I actually redid the test in my home country, living abroad at the moment, and the result was very different. This time I got a risk evaluation on 1:7063, compared to the 1:201 I got the last time. So I'm just taking it easy now. Have an ultrasound in week 19th so hopefully everything will look good then too.
At Tue Sep 30, 07:51:00 AM 2008, Anonymous said…

HI Dr. T;
My name is Elizabeth 31, 2nd pregnancy I went to my second ultrasound and the technician didn't see the nasal bone present. Specialitst and GYN advised me to wait because everything else looks normal NT and blood test. But I cou;dn't I decided to to the amnio. Big Fishes came back normal but I'm still waiting for the rest of the report. What happens next? Do I need to worry about anything else? Can the baby be normal without the nasal bone? Can that bone calcified in the next weeks? My next ultrasound is 10/21. Should I be concerned still? Thanks Elizabeth
At Fri Oct 03, 10:47:00 AM 2008, Anonymous said…

Hi Dr. T,

I just wanted to follow up from my initial post of September 18th. I had the CVS test done and just got the results back and everything came back normal. I can't tell you how stressful these past couple of weeks have been but I'm happy that we're ok now. I wish everyone else the best in their outcomes! Maria
At Fri Oct 03, 06:35:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Wendy: Pardon the delay in my response but Healthline is way behind on sending me comments. Thanks for the additional information. What sort of combined thrombophilia do you have and what workup have you had done? This might have contributed to the complications with both your pregnancies. Please let me know and I might have some suggestions. Dr T
At Fri Oct 03, 06:36:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Wendy: Pardon the delay in my response but Healthline is way behind on sending me comments. Thanks for the additional information. What sort of combined thrombophilia do you have and what workup have you had done? This might have contributed to the complications with both your pregnancies. Please let me know and I might have some suggestions. Dr T
At Fri Oct 03, 06:43:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Mimi Sept 19: I think the results are very good. The NT measurements are well within normal range as are the hCG and PAPP-A. You should be at very low risk for Down syndrome, trisomy 18 and trisomy 13. Best wishes for the rest of the pregnancy. Dr T
At Fri Oct 03, 06:46:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Lara Sept 20: No, not at this early gestational age. At your age, the risk for a chromosomally abnormal baby is high. And, if the baby is chromosomally normal, then he/she should be very carefully evaluated for a heart malformation. Why did the one doctor thnk this could be an infection? Please let us know how things turn out and best wishes. Dr T
At Fri Oct 03, 06:50:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 21: What was the actual composite risk result? There are "positives" and then there are "POSITIVES." Not all "positives" are equal. And, if the baby has "always measured a week behind" could you possibly have ovulated a week later than you thought. That might also skew the test results. "Placental insufficiency" at this very early gestational age is fairly unusual, even if there is a less than optimal placentation. Best wishes. Dr T
At Fri Oct 03, 06:54:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 23: An NT measurement alone can pick up only about 50% of Down syndrome babies and should not be interpreted in the absence of the serum markers, especially since your baby had one at the high end of the 'normal' range. The strength of the "combined test" is the value of using all the information you can get! You might ask for a second opinion with a specialist in maternal-fetal medicine since there even seems to be some discrepancies in the accuracy of the NT measurement. Best wishes and let us know what you find out. Dr T
At Fri Oct 03, 06:56:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 24: Thanks for the feedback. I am sure many readers will appreciate the information. Dr T
At Fri Oct 03, 06:58:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To May: Those results are WONDERFUL. I would think long and hard before risking this pregnancy on an amniocentesis under these circumstances. Remember, since two amnios may have to be done, the risk of the procedure is also at least doubled! Good luck and let us know how things turn out. Dr T
At Fri Oct 03, 06:59:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To anonymous Sept 30: Thanks for letting us know. Best wishes for the rest of the pregnancy! Dr T
At Fri Oct 03, 07:01:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Elizabeth Sept 30: If teh FISH studies were normal, there is a very good chance the baby does not have a chromosomal abnormality. Not all babies develop a nasal bone at the same time in pregnancy and there are ethnic differences as well. Odds are everything is good. Let us know how things turn out and best wishes for the rest of the pregnancy! Dr T
At Tue Oct 07, 06:59:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Maria: Congratulations and thanks for letting us know. Best wishes for the rest of the pregnancy. Dr T
At Mon Oct 20, 07:56:00 AM 2008, Wendy said…

Thanks so much for your response. I posted my history back on August 1. 4 early miscarriages, 2 healthy full term pregnancies (1 natural / 1 IVF), 1 preterm birth with severe IUGR and a limb defect, and most recently a 16 week fetal demise with placental problems and limb defects. I am heterzygous for Factor V and compound heterozygous for MTHFR C677T/A1298C. I also tested low for protein S activity but I'm told that some people with factor V do. I've had all the other clotting tests, APA, Prothombin II, Factor VIII... and they are all normal.

When I last posted a comment we were awaiting chromosome results from Childrens Hospital in Philadelphia. I had a genetics consult and was told it's possible it's genetic because limb defects don't generally occur twice. Both cases individually look sporadic but the two together is suspicious. They weren't putting much weight into the thrombophilia. My recurrence risk is as high as 25% apparently.

They also told me however that chromosome testing was done and standard karotyping was normal. They did CGH on fetal tissue and the result was tetraploidy mosacism. They are doing further analysis to see if it's a true result or the result of contamination. Even if it's true, the aren't sure if it is the cause.
At Wed Oct 22, 06:40:00 PM 2008, Kenneth F. Trofatter, Jr., MD, PhD said…

To Wendy: Thanks for updating us on your situation. I do not have any kind of response at this point but I am very curious to find out what has been going on in your case (if they do!). Please stay in touch. Kind regards, Dr T

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