For many women, an ultrasound performed around 20 weeks gestation offers the first chance to see their baby.

A newer screening test, the first-trimester screen, provides an earlier ultrasound and, along with a blood test, can indicate an increased risk for Down syndrome or trisomy 18 (conditions that result from an extra chromosome) as well as other conditions. This test can be performed between 11 and 14 weeks gestation.

The ultrasound component of the first-trimester screen measures a thin layer of fluid at the back of the baby’s neck called the nuchal translucency (NT). The screening is safe for both moms and babies.

A blood test measures the levels of two proteins, Beta-hCG (the pregnancy hormone) and PAPP-A. Women who are 35 and older are routinely offered the opportunity to meet with a genetic counselor to discuss screening and testing options available during pregnancy. Carrie Couyoumjian, M.S., a certified genetic counselor at the University of Michigan Health System, says that the increase in the number of women who undergo first-trimester screening has caused a decrease in the number of amniocentesis procedures performed. Screening allows a woman to obtain more information about her pregnancy before making a decision to have an amniocentesis, an invasive test which is associated with some risk of miscarriage.

Women who undergo first-trimester screening and whose embryos are found to have an increased risk of Down syndrome or trisomy 18 are offered diagnostic tests (such as chorionic villus sampling [CVS] and amniocentesis) and the opportunity to discuss their test results with a genetic counselor through the U-M Perinatal Assessment Center.

First-trimester screening can’t guarantee a completely healthy baby, but it does offer some reassurance and a chance to obtain some information about a pregnancy without the risk of invasive testing.

First-trimester screenings are scheduled at the Perinatal Assessment Center at (734) 763-4264. It is important to check with your insurance company to confirm that the first-trimester screening is a covered benefit.