Invasive Diagnostic Testing after Reassuring First Trimester Screening for Aneuploidy?
Tuesday, January 22, 2008
Kenneth F. Trofatter, Jr., MD, PhD
Dr. T - I wrote to you a few months ago on your recurrent loss blog regarding my two 2007 1st trimester losses - I followed your advice to see a good RE (reproductive endocrinologist), we found impaired glucose tolerance, I started metformin, and I am happy to report that I am 15 1/2 weeks pregnant with what seems to be a healthy baby! So, thanks for that.
Here's my new question: I just turned 39. I had a NT done, and my risk for Downs is 1/2000 and my risk for Trisomy 18 is 1/3700 - which is reassuring. I scheduled an amnio anyway, because I am 39, and because of the possibility of the chromosomal problems with my lost pregnancies last year. Now, I am a week away from the amnio, and I am getting paranoid about the risk from the amnio of losing this baby. What I don't quite understand is how a history of previous losses impacts the risk of amnio. Does it make a difference if your previous losses were not spontaneous miscarriages, but missed ones? I was ok with my decision to have an amnio until yesterday, and now I can't get past the thought that something bad might happen. I know that my doctor doesn't care either way if I do the test or not, but I don't want to talk myself out of (or into) something if I am being overly cautious. Thanks in advance.
Liz
Tue Jan 22, 09:25:00 AM 2008
Kenneth F. Trofatter, Jr., MD, PhD said...
To Liz Jan 22: Liz, I am not going to tell you what to do. But, let me put this in perspective. The risk of the amniocentesis in experienced hands is still about twice that of your a priori risk for having a baby with Down syndrome or trisomy 18 (and probably several other chromosomal abnormalities as well) based on your first trimester screening results. In less experienced hands, the amniocentesis risk can be 10 times your first trimester screening risk! With those odds, if you did happen to be the 1 in 1000 (or 1 in 200) who lost their baby as the result of the amniocentesis, the overwhelming odds are that you will lose a completely NORMAL baby.
You are doing very well, you have been through a lot to get to this point, odds are this baby is normal, and you are 39 years old. You may not have many more opportunities if this one is lost. One option to consider, rather than jumping into the amniocentesis now, is to simply have a genetic sonogram done at 18-20 weeks. If that is normal, your a priori risk (based on the first trimester screening results, NOT your age) is reduced by at least another 50% (I generally quote folks 60-80%). So, answer me this...how does a 1 in 4,000 risk sound to you? If something really suspicious is seen at that point such as poor fetal growth, congenital heart defect, or a major marker for aneuploidy (and I am NOT talking about an echogenic intracardiac focus, or even a choroid plexus cyst alone), you could still opt for the amniocentesis with a FISH (fluorescent in situ hybridization) analysis for the more common types of chromosomal abnormalities. This can give you highly reliable results within 72 hours. Using first trimester screening, coupled with this approach, we have not missed a chromosmal abnormality in more than three years, nor lost a baby from an amniocentesis. By the way, CONGRATULATIONS! Again, best wishes to you and please let us know how you do with the pregnancy!
Dr T
Tue Jan 22, 05:27:00 PM 2008
Labels: amniocentesis, aneuploidy screening in first trimester
10 Comments:
At Fri Jan 25, 10:21:00 AM 2008,
Anonymous said…
Just read the previous msg with regards to previous lost pregnancies and age. My situation is similar in that I am 42 with 3 lost pregnancies in the last 10 years. We were not really trying to concieve except for the 1st pregnancy in 1997 which resulted in about 18 hrs of labor in an ER in my 3rd month. Anyway, Surprise to us we became pregnant last Sept 2007. My concern is that this is my last chance so how ever the baby turns out having an amniocentesis or any other genetic testing is irrelevant. Now at 19 weeks we had a 2nd ultrasound and my baby was found to have a Choroid Plexas Cyst. ONE at aprx 11x7 cm The doctor told my husband & I that it is relatively a small cyst and located in the skull/brain area that is where fluid usually resides but this fluid developed tissue around it forming a cyst. She said that if the next ultrasound in 2 months shows any other genetic markers (as no other marker were found at this time) then she would insist on full genetic testing ie amniocentesis, ect. I don't know much about that sort of testing as I have never gone through it. But how can she insist on it??? It's my baby. If I want to know in advance then that would seem to be my decision. The baby will come out either healthy or not and my husband will love & take care of him (it's a boy by the way) the best we can afford to. So who is she to say that she will insist?? All she is doing by running those extremely $$$ expensive tests is to take money out of our pockets that we will need for our new baby. Unfortunately like many Americans we have very lousy insurance. It was great when we lived in CALIF and even in AZ But here in Nebraska where insurance companies don't care to compete the insurance plans just are lousy-unless one works for the railroad or the hospital. *** JUST wanted to know your thoughts on this matter and I don't know much about Choroid Plexas Cyst. THX frm a Housewife in Scottsbluff, NE
At Fri Jan 25, 11:50:00 AM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Jan 25: Your doctor cannot INSIST that you do that and you always have the right to find another one if that's the way she/he deals with sensitive situations like this. I have said this before and I will say it again, the diagnosis of 'choroid plexus cysts' and labeling these as an "ABNORMALITY" is one of the greatest disservices ever done to obstetrical patients. I have known women who have terminated perfectly healthy babies (without even having an amniocentesis done!) simply because they were told the baby had CPCs and could be at higher risk for a chromosomal abnormality. Personally, I consider 99%+ choroid plexus cysts to be a NORMAL DEVELOPMENTAL VARIANT. Early studies did show that babies with trismoy 18 had a high rate of choroid plexus cysts, but the opposite is NOT TRUE - in other words, MOST BABIES with CPCs do NOT have chromsomal abnormalities (and most babies with trisomy 18 have LOTS of other things wrong with them that would have led to that diagnosis anyway). I counsel patients in whom we find CPCs (and frankly, I wish we didn't even have to tell them, and sometimes I don't) that in the presnce of normal fetal growth and in the absence of a MAJOR fetal abnormality or significant 'marker' for chromosomal abnormality (such as a thickened nuchal skin-fold) the overwhelmong odds are that the baby is chromosomally normal. Incidentally, most CPCs will be gone by 24-26 weeks and no one has ever shown that the common CPCs that we see are associated with ANY long-term problems for the baby by themselves. Take a deep breath, relax, and enjoy the rest of your pregnancy. Thanks for reading and let me know if I'm wrong! Dr T
At Thu Feb 07, 02:47:00 PM 2008,
Anonymous said…
I just found the site and we are debating what to do (we have gone back and forth numerous times). We got a good First Trimester screening (1:4301 for DS and 1:7861 for Trisomy 18/13) I am 36, the NT was 1.3 wiht delta NT of -.3 CRL 63.3. I am concerned about the blood test portion which was Free Beta hCG MOM: 2:59 (95%) and PAPP-A MOM: 1:97 (80%). How could our results have been so good if the blood was not great. Do you recommend amnio?
At Sat Feb 09, 11:08:00 AM 2008,
Liz said…
Dr. T - you had asked me for an update. I followed your advice, we got an ultrasound first, and we were still considering whether to do the amnio, after that looked good too. We didn't find a good spot for the needle, so we decided to put it off for 2 weeks.
Unfortunately, fate intervened in the interim and little Shannon had a cord accident at 17w5d and died. I delivered her yesterday morning. She looked absolutely perfect in every way, and we would be surprised if we find anything wrong on autopsy. We do intend to try again soon, given that I am 39 and the clock is ticking.
Thank you again for all of your guidance through my losses and the amnio questions. I hope that we get to make these decisions about an amnio again soon. I am sure that I'll be back in touch with more questions then. One last question, if you don't mind, after childbirth, when can I expect to ovulate again? Is this bleeding like the first day of my cycle?
Liz
lizsmailbox@aol.com
At Thu Feb 14, 07:13:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Feb 7: I think the overall 'composite result' was probably good because the NT was VERY good and the serum markers were BOTH on the high end. Perhaps you were just a little further along or you have a slightly larger, and healthy placenta. If the hCG had been high and the PAPP-A was low, you would be at increased risk for Down syndrome and if both were LOW, you would have been at greater risk for trisomy 18. At this point, trust the computer calculation to have given you reliable information because the composite result is GREAT. Let us know how things turn out and thanks for reading. Dr T
At Thu Feb 14, 07:16:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Liz Feb 9: I am so sorry. Most women will ovulate within 6-8 weeks following a loss in midtrimester. Remember, you will ovulate (and therefore could get pregnant again) BEFORE you have your next normal period. I will be thinking about you and thanks for sharing your story with us. Dr T
At Thu Mar 20, 08:27:00 PM 2008,
Anonymous said…
Dear Dr. Trotter:
I am a 35 yr old who is 13 weeks pregnant. This is my first pregnancy and I am seeing a high rish specialist since I had bleeding from week 4-6. Two weeks ago, I had CVS and the preliminary results (I assume FISH) results showed a healthy baby girl without any chromosomal abnormalities. A week later the genetic specialist called me and told me the final results showed mosaic turner's syndroms and that I need to have an early amniocentesis to determine if this finding is limited to the placenta only. Why did the preliminary results show a false negative? Should I rely on the fish results from amniocentesis in order to make my decision regarding termination or wait for the final amniocanetesis results? Thank you!
At Sat Mar 22, 03:23:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Mar 20: Great questions so I wrote a full post on the subject March 22, 2008. Thanks for reading, good luck with your tests and please let us know what you find out! Dr T
At Wed Jul 16, 04:42:00 PM 2008,
anonymous said…
Dear Dr T
Just found this site and took alot of encoragement from it. I an agonising over the amnio and have been for the passed 4 weeks i am now week 20 and this is my last chance to have it. My age is 42 i got pregnant very quickly and my test results were nuchal 1.3 beta fg 1.6 and pappa 2.5 overall risk 1/1250 at 12.5 weeks. I decided not to have amnio based on this and an now so anxious about the prospect of Downs I feel quite ill with the worry. My local hospital claims their amnio miscarriage rate is between 0.5 and 1.0 per cent. I am torn between no getting pregnant again given my age and driving myself ill with stress of not knowing for sure.
many thanks anonymous
At Fri Jul 18, 05:23:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous July 16: I cannot make the decision for you, but I will tell you four things: 1) You got a GREAT test result for your age; 2) The quoted risk of the amnio at your hospital is 5 to 10 times greater than the chance that this baby has Down syndrome; 3) If you lose the baby as the result of the amnio, odds are you will be losing a NORMAL baby; and 4) If you get pregnant again, the odds are about 20-25 times greater than your current risk that you will have a chromosomally abnormal baby! But, the final choice is yours and you have to live with whatever decision you make, so best wishes! Dr T
Post a Comment
<< Home