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All About First Trimester Screening

Discover what these early tests look for—and why they're needed.

Wed, 12 Dec 2012|

First trimester screening is relatively new, and it's a blood test and sonogram that checks the genetics of the baby. One of the big concerns over time has been chromosomal abnormalities for the baby, Down syndrome, Trisomy 13, Trisomy 18, these sort of dangerous conditions that lead to babies that may not even survive birth. The beauty of the first trimester screen is that it's a noninvasive test. A blood test done in our practice at 9 weeks combined with a sonogram that's done at 11 weeks and then it will give a patient an estimate of her risk for Down syndrome, and then our patients use that estimate to decide what further testing they do or don't wanna do. In the first trimester screening ultrasound, the sonographer is looking at the thickness of the baby's neck because there's a certain measurement that's within the range of normal, but if the baby's neck, the back part of the baby's neck is thicker than this average number, then that can show a risk of Down syndrome. In my practice I send the blood component 2 weeks earlier to the lab that runs the blood component, and then when our patients go for the sonogram, you know, there are 4 data points to get the result; 3 from the blood and 1 from the sonogram. And so if we've sent the blood ahead of time, then when they get the sonogram, they have all the data and they can give you the result right there on the spot. So it's right at that very moment when you have the sonogram. When a patient has a low risk for Down syndrome based on the screening test but she's nervous that it's not 100 percent answer, now this patient could choose instead of doing the amnio and having the risk of miscarriage, she could choose to do this new blood test called MaterniTY 21 and get on paper a 99 percent answer about her pregnancy, and so that seems very, very powerful. What this test is doing is it takes the mother's blood and then looks in the mother's blood for tiny fragments of cells from the baby. So that even at you know 10, 15 weeks pregnant, our bodies have little bits of genetic material from our baby which is a fascinating concept to begin with, and using, you know, modern technology those tiny fragments are identified and magnified and then tested to see if the baby has Down syndrome.