Another Reader's Questions Regarding First Trimester Screening for Aneuploidy
Friday, September 14, 2007
Kenneth F. Trofatter, Jr., MD, PhD
I received my screening results and was given a 1:86 chance of having a baby with Down syndrome (trisomy 21). I am 35 years old. Only my hCG levels were elevated. My PAPP-A was 1.4 and the baby's NT (nuchal translucency) was 2.4mm which I was told was at the 90%ile for the size of the baby and anything above 95% is considered elevated. Given that I don't "fit the pattern" with elevated hCG, decreased PAPP-A and elevated NT- am I facing better odds that the baby is fine? Could my hCG levels be elevated "just because" that's how I am?
Kenneth F. Trofatter, Jr., MD, PhD said...
To Anonymous Sept 14: I had a similar query from a reader and responded to her on that post on July 17. The answer is basically the same. The odds are what they are, regardless of the combination of measurements, serologic markers, and demographic information that led to them! You have a 1 in 86 chance of having a baby with trisomy 21. (That is about twice your 'age alone' risk and probably a more reliable 'risk estimate' as well because it is derived from real numbers based on your pregnancy and not just from the population-based risk of women at your age). That also means you have a 85/86 chance the baby does not have trisomy 21.
The important questions you must ask yourself are "How do I feel about those odds? Do I need some more information? Do I want to find out for sure whether or not the baby has a chromosomal abnormality before the baby is delivered?" If you would prefer not to have an invasive study done at this time, there are other options to consider. You could have an early anatomic survey of the baby done by ultrasound at 16 weeks and possibly couple that with a maternal serum marker panel ("quad screen") which will give you another asssessment of "risk." Some laboratories will combine the first and second trimester data into a single 'integrated' risk assessment. And/or, you could have a 'genetic sonogram' done at 18-20 weeks. If that is completely normal, your a priori risk (based on the screening tests, not your age) for a baby with trisomy 21 can be reduced 60-90% depending on the experience of the ultrasonographer.
Thank you for reading and my best wished for your pregnancy.
Dr T
Labels: first trimester screening
6 Comments:
At Sun Sep 16, 11:15:00 PM 2007,
Anonymous said…
It seems that we have addressed the risk of downs with the first trimester screening. Well, my results were a little different. I received them a week ago. I'm set to talk more in depthly with a genetic counselor in a week but between now and then I feel very worried. I was told I had a 1 in 20 chance of the baby having downs and a 1 in 6 chance of Trisomy 18. I don't know what to think of all of this. It all seems like high odds to me. I'm quite worried and I don't know what avenues I'm going to take. I will be forty when we have our baby. Anyones imput is very much welcome. Feel free to use my email directly if you desire. sunsetsnthunder4@aol.com
Thanks
Kim
At Mon Sep 17, 09:04:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To sunsetsnthunder4 Sept 1: I am sorry, but those risks are VERY high. If you want a diagnosis,and are still early enough, I would recommend chorionic villus sampling (CVS). If you are beyond 14 weeks, an amniocentesis can be done safely in experienced hands between 15 and 16 weeks. Good luck and thank you for reading. please let me know what happens. Dr T
At Sat Sep 22, 12:55:00 AM 2007,
Anonymous said…
Hello Dr Trofatter,
I wanted to write you back with un update. I met with my genetic counselor and she tole me that my PAPPA was .22 and my HCG (I think that is what it is) was .58 so that is what pushed my odds so very high. After this discussion and your post to my questions I decided to go forward with a CVS. The proceedure was not bad at all. And today I got my results. Everything is perfectly normal and we are having a boy!! So I thought you might want to know the results and also know how it is all turned out. I do understand that with the PAPPA being so low there are other risks that might still face us. I thank you for taking the time to reply back to my post. And I thank you for your candid advice. Sincerely, Kimberly Sharpe
At Fri Sep 28, 10:37:00 AM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
Kimberly: Thank you so much for letting me know! I wish you the best for the rest of the pregnancy. Boys always start out life giving their mothers a hard time! Regards, Dr T
At Thu Jun 12, 12:15:00 PM 2008,
Anonymous said…
at out 12 week nt scan our baby was found to have a nuchal transluceny of 7mm. We were told that more than likely the baby had Down or Turner's Syndrome. We immediately opted for CVS, figuring that it would be best to prepare ourselves. Although there is some discomfort, the procedure itself is not horrible. The risk of miscarriage is slight. We were told we would have FISH results in 3 days. Also they did an additional ultrasound and our angel has a cystic hygroma that developed into hydrops. This is a symptom ususally of a chromosomal abnormality. We recieved our results praying for a miracle but coming to terms with reality, which is our baby has Trisomy 18, or Edwards Syndrome. The prognosis is never good as this is one of the most devasting trisomy conditions. My advice is to listen to your doctors. They know what is best. You can never prepare for things like this but unfortunately they happen to those who never think they could. I am 31. Not high risk. Good health for me and my husband. We thought the odds were in our favor. I hope you find our story helpful.
At Sun Jun 15, 09:16:00 AM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous June 12: I am so sorry and thank you for sharing your story with us and the comments related to physicians. There are very few of us that would intentionally lead a patient astray in our recommendations or hope for a bad outcome. Fortunately, it is unlikely that you would have another baby with trisomy 18. Kind regards, Dr T
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