Find out what different prenatal tests are recommended based on a mother's age

Women are born with all the eggs we will ever have, and our eggs age along with us. At age 35, the risk of having a child with a genetic defect is increased, but is still far less than one percent. Unfortunately, the risk increases dramatically each year after that.

There are prenatal tests that are recommended based on the mother's age. These tests are designed to help identify mothers who may be carrying a baby with a genetic abnormality such as Down syndrome.

Currently there are two noninvasive screening tests: the first trimester nuchal translucency and the second trimester maternal serum screen. Many insurance companies will not cover the cost of a nuchal translucency in women who are not at increased risk, so most women under 35 are offered the second trimester maternal serum screen, which is sometimes called the quadruple or "quad screen." It is called the quad screen because four different chemicals in the mother's blood are checked. Typically the test is performed between 15 and 18 weeks of pregnancy and requires a small blood sample from mom.

The quad screen does not yield a definitive yes or no result, but rather identifies women who may potentially have a baby with three chromosomes of 21 or three copies of chromosomes 13 or 18 (this is also called trisomy). The quad screen can also potentially identify women who may have a baby with spina bifida.

All women who have an abnormal quad screen are offered amniocentesis or chorionic villus sampling (CVS) to confirm results with cells from the baby.

These may be obtained by an amniocentesis
In addition to the increased risk of genetic defects, pregnant women over 35 are also more likely to have other complications with their pregnancies, such as gestational diabetes, preeclampsia and preterm labor. There are additional prenatal tests that may be performed to help evaluate for these risks, including blood tests and fetal fibronectin testing.