Prenatal testing can be a multi-edged sword. Usually, test results are reassuring, which puts expectant parents’ minds at ease. But some people argue that because birth defects are rare, these tests in most cases cause undue stress; others argue that they allow people to create “designer” children. Then there are the parents who discover very real, sometimes dire, problems with their babies and face the decision of whether to keep or terminate a pregnancy. Testing is a difficult and confusing issue, and what’s right for one family may be entirely wrong for another.
Some women opt out altogether, claiming that even if a problem were detected, they would never terminate a pregnancy. Others choose to undergo blood screening tests but nothing invasive, such as amniocentesis. Still others say yes to every procedure offered to them, wanting to gather as much information as possible about the fetus’s health—and, hopefully, reduce their anxiety along the way.
“Testing is a very sensitive issue, and a very personal one,” says Barbara M. O’Brien, M.D., a geneticist and maternal-fetal medicine specialist at Women & Infants Hospital in Providence, R.I. “Patients can feel pressured to opt into screening, but they shouldn’t be. It’s a personal decision.”
The topic can be so delicate that prospective parents should start considering it very early, even when they begin planning a pregnancy. “The clock is ticking once you conceive,” explains certified nurse-midwife Barbara L. McFarlin, Ph.D., C.N.M., of the department of women, children and family health science at the University of Illinois at Chicago College of Nursing. “There are certain windows when tests have to be completed.” Following are the most common screening and diagnostic tests currently being given, along with a few other types most moms-to-be have. But which you are offered, and which you choose to undergo, may vary according to your age, where you live, your personal or family history, and many other factors.
3 Types of Tests and What They Can Tell You
Most women are offered a screening test in both the first and second trimesters. Your results will come back as either “screen positive” or “screen negative,” along with a specific risk. “A screening test will never give you a ‘yes’ or ‘no’ answer,” says genetic counselor Cathy Wicklund, M.S., C.G.C., director of the graduate program in genetic counseling at Northwestern University in Chicago. “All they can do is quantify risk.”
Every woman interprets risk differently based on her personality, her education level, even the way information is presented to her. But perhaps most influential is her life experience. “If you’re the one person who got struck by lightning, you’re going to think that in a 1-in-100 risk scenario, you’re going to be that one,” Wicklund says.
Unlike screening tests, diagnostic tests can confirm a birth defect exists by studying tiny samples of a fetus’s genetic material. Approximately 5 percent of women are referred for diagnostic tests following screening; O’Brien says the incidence of diagnostic tests is decreasing because of improved screening tests.
In addition to the tests described here, you’ll likely undergo a urine test at each prenatal visit to check for bacteria, which could signal a urinary-tract infection, and protein, a potential preeclampsia symptom.