Is prenatal screening right for you?

Prenatal screening includes a variety of tests that are designed to assess the health of both mother and child. While there is no test that can guarantee a healthy baby, prenatal screening can provide prospective parents with a sense of preparedness and reassurance.

However, though some of these tests are standard, such as routine blood work and the glucose tolerance test, others are controversial due to their inherent risks. Maternal serum screening, a blood test that estimates the probability of a potential birth defect, can provide false positive results, which often require further testing, not to mention unnecessary stress and anxiety.

Dr. Kimberly Heller of Health Quest Medical Practice in Poughkeepsie, explains: “Screening tests screen, but do not diagnose a condition. A screening test identifies a portion of the population at higher risk for a condition who may benefit from further diagnostic testing.  So, if a woman has a positive penta screen, this means she may be at higher risk than the general population to have a baby with Down syndrome. It does not mean that the baby actually has Down syndrome. Further testing (with amniocentesis or CVS) would be needed to make the diagnosis of Down syndrome.”  Dr. Heller is a Maternal Fetal Medicine Physician.

Amnio and CVS

Amniocentesis and chorionic villus sampling (CVS), which involve inserting a needle through the belly into the uterus to remove cells from the amniotic fluid or placenta, pose risks such as miscarriage. And even though these tests have the ability to diagnose chromosomal abnormalities and genetic deformities, they cannot tell you the severity. The process can make parents anxious, and because many tests are based on percentages and probability, results are often left up to the doctor’s interpretation.

Stacey Foster, 40, a mother of two living in Port Ewen, says, “I refused the triple screen for our first child but was told to do it for our second due to my age.” Women over the age of 35 have an increased risk of conceiving a baby with a genetic abnormality. Foster adds, “For us, the test caused a lot of anxiety. I had a high positive rate, which led to much more invasive testing. The CVS was painful, but the most painful part was waiting for results. It turned out the triple screen had been a false positive, and the CVS, in my opinion, was for nothing.”

A personal decision

If you’re in a high-risk bracket, genetic testing is worth considering. At the same time, you might want to contemplate what you will do if a health problem is detected. If it isn’t going to change the path of your pregnancy, you might decide not to go through the pain, stress, and anticipation of testing.

“The issue of pregnancy termination is probably the most controversial topic related to genetic testing,” says Heller. “Pregnancy termination is an option until 24 weeks of pregnancy in New York. Some women would choose pregnancy termination for a significant genetic abnormality, others would not. It is a very personal decision which also requires accurate medical information about the genetic disease diagnosed.”

Jennifer Fugal, 30, a mother of four living in Olivebridge, says, “We never had any genetic testing done for any of the babies. It was our feeling that if something was wrong with our child, we wouldn’t do anything different, so why take the test just to be stressed out and possibly cause harm? But with my third, I had a thin uterine wall from my previous pregnancies and we needed to deliver the baby as early as possible. I had two amnios to test for fetal lung maturity to make sure it was okay to deliver. Her lungs were ready at 38 weeks and we delivered the next day.” 

Talk to your doctor

Speaking to your doctor to find out exactly what the tests will and won’t tell you, what’s involved, and what the risk factors are can help alleviate fears and misconceptions while allowing you to make an informed decision. It’s important to remember that while medical professionals offer these tests, they are not obligatory. You can always opt for some tests while declining others.

As prenatal testing becomes more refined, parents will continue to face more difficult decisions. According to Heller, “We will soon have the ability to analyze the entire genome of the developing baby, determine every genetic mutation the baby carries, all of the baby’s genetic traits, and the genetic predispositions to disease — all from a maternal blood test performed in the first trimester.” Parents will have more information than ever before. How each family makes use of that information, or whether they even want to know, is a very personal matter, and only the patient can decide which tests are right for her.

• Medical and family history, age, and ethnic background are all factors in deciding whether a woman’s pregnancy is considered high risk.
• Pregnant women over the age of 35 are automatically candidates for amniocentesis because the risk of having a baby with Down syndrome increases dramatically as a woman gets older (3 in 1,000 for a 35 year old; 1 in 100 for a 40 year old).
• Women who have a family history of genetic disorders, such as cystic fibrosis, sickle cell disease, or Tay-Sachs disease, may opt for a carrier-screening test to see if she or her partner are carriers.

Prenatal testing roundup

Amniocentesis: A thin needle is inserted through the abdomen into the uterus. Tests for Down syndrome, neural tube defects, and some genetic disorders

Carrier screening: Blood or saliva is tested to see if parents are carriers for genetic diseases such as cystic fibrosis, sickle cell disease, or Tay-Sachs disease

Chorionic Villus Sampling (CVS): A thin needle is inserted through the abdomen into the uterus to test for Down syndrome and other chromosomal abnormalities

Glucose tolerance: The patient drinks a glucose drink and then takes a blood test to check for gestational diabetes

Nuchal translucency screening: A high-tech ultrasound that detects the risk of Down syndrome and other abnormalities, as well as congenital heart problems

Routine blood work: Tests RH status and anemia. May also test for syphilis, hepatitis B, and immunity to diseases such as rubella and chicken pox.

Triple screen: A blood test that screens for three different substances to find out if your baby is at risk for certain chromosomal problems and birth defects, generally done before an amniocentesis or CVS. “Womb Service” about her time on pregnancy-related bed rest.

Aileen Weintraub is a freelance writer living in Ulster County. She is currently writing a memoir entitled “Womb Service” about her time on pregnancy-related bed rest.