I am 12 weeks pregnant and recently received the Trisomy 18 diagnosis . . .
It’s the worst news possible for a new mother — you’ve just been told that something terrible is wrong with your baby called Trisomy 18!
This is usually the point where we hear from a new parent who has turned to the Foundation for help in getting a handle on this devastating news. But is it devastating news? Has this much-wanted pregnancy really been diagnosed at 12 WEEKS?
We regularly heard from mothers and dads around 15-18 weeks gestation after learning they were AT HIGH RISK for Trisomy 18 or at about 18-20 weeks that their baby had been DIAGNOSED with Trisomy 18. But now these shocking moments are coming much earlier in pregnancy and that presents a different set of circumstances we need to get clear about before we can even begin to talk about what to do once diagnosed. Why? Because this baby has not been diagnosed yet and may not even have Trisomy 18! There is a big difference between the information you need when you are “circling the island” with a “possible” Trisomy 18 diagnosis versus the information you need and the emotional impact of actually “landing on the island” with a real Trisomy 18 diagnosis for a much-wanted child.
Why the growing confusion? Here’s what I replied to this mother in our Online Community:
A: Hello new Momma,
I’m sure this news has you scared to pieces, as it would anyone. But I’m not sure you’ve gotten a diagnosis yet. At 12 weeks the tests that are available are all SCREENING tests, meaning they are made to determine is the child you are carrying is at RISK for having Trisomy 18 and (depending on the test being used) how high that risk is as a ratio like 1 in 10 or 1 in 566, etc.
There are newer NIPS tests (non-invasive prenatal screening) that attempt to lower the numbers of false positives and false negatives with the maternal serum tests, but they only screen for T21(Downs) and T18 and T13. The maternal serum screening tests (sometimes called the Quad screen or Triple screen) is screening for a much larger set of possible birth defects, including neural tube defects.
But the main point is that these are ALL screening tests. The next step recommended as best practice by all the professional societies involved in the care of pregnant women (like ACOG, SMFM, ISPD, ACMG, NSGC, etc) is for a “positive” test suggesting the possible presence of one of the Trisomy conditions using NIPT tests is a referral to a Maternal Fetal Medicine Specialist for more in-depth screening. That will include a detailed anatomical ultrasound looking for possible physical markers associated with Trisomy 18 and if warranted, an amniocentesis to definitely diagnose the condition. Only an amniocentesis (or a CVS) can actually DIAGNOSE Trisomy 18 because it is extracting the actual cells from the baby and culturing them so that one can look directly at the chromosomes and literally count them. It’s called a karotype. The screening tests are designed to minimize the number of women being referred to Genetic Counselors and MFMs for an amniocentesis. But even the MFM will always start with that anatomical high-level ultrasound because if there are NO markers present, it suggests that the blood test “might” be a false positive. (Oh, and BTW it is possible to receive a false negative as well where you’ve been told there is no risk, but the baby does have Trisomy 18.)
In my case, my baby son passed the anatomical screen free and clear and we did not have an amniocentesis but he DID have Trisomy 18 — so that can happens too.
I’m sorry this is all such a stressful process, and I know how deeply worried you are, but as someone who delivered a much-wanted baby son without a prenatal diagnosis, I can tell you being surprised at birth is not what anyone would want. It can definitely limit the options you have immediately available to provide the best care possible to you and your baby and make the most of what might be a limited time with each other as a family. That takes some advance warning and preparation and being in the best hospital with a high-level NICU.
