Genetic testing helps parents make informed decisions

Having a baby can be an exciting but stressful time that is full of unknowns. During pregnancy, there are many doctors’ appointments and tests performed to ensure the baby is growing and developing at a normal rate. Parents-to-be have the option of undergoing genetic testing to make them aware of any possible complications with their baby’s development.

“We usually talk about genetic testing during the very first prenatal appointment,” says Aneesha Varrey, MD, an obstetrician-gynecologist with GBMC Health Partners Perinatal Associates, who specializes in maternal and fetal medicine. “It’s offered to women who want to make sure their baby doesn’t have a genetic abnormality that could affect his or her quality of life.”

The genetic tests are done through a blood test of the mother, who has the baby’s DNA in her bloodstream. Dr. Varrey explains, “Every cell has 46 chromosomes, which are like small packages of genes, and all of us have a map as to how those genes are supposed to align. When they’re not aligned in a certain way, or if there’s an extra chromosome, it’s considered an abnormality.”

The most common abnormality is having an extra copy of chromosome 21, which can lead to Down Syndrome. The risk of this abnormality varies with the mother’s age and not family history, says Dr. Varrey.

“After age 35, women produce eggs with more chromosomal abnormalities. Before that age the risk of abnormality is 1- in-110, but after age 40, it jumps up to 1-in-40.”

She says blood test results are more of a warning signal, not a diagnosis.

“No life-altering decisions are made immediately after the screening test. We’ll schedule a diagnostic test to examine some placenta cells or amniotic fluid, then test those cells to see if the pregnancy is affected.”

The hardest part for the parents, Dr. Varrey explains, is the waiting period from when the diagnostic test is performed to when they receive the results.

“It usually takes 10 to 14 days to get results back, and it can be hard for the parents to bond with the unborn baby during that time.”

She says once the results come in, if the baby does have an abnormality, the staff at GBMC is there to help parents with their decision to either continue the pregnancy or terminate it and to talk about if the same situation could be prevented in future pregnancies.

“Having an extra chromosome is usually just a random occurrence,” she says. “One of the parents could have a rearrangement of chromosomes that doesn’t affect their life in any way, but it can cause mutations in a baby’s development. If this is the case, there are options like IVF that parents can explore.”

She adds that, with medical and technological advances, quality of life and outcomes for babies born with Down Syndrome are much better than in the past.

“There are so many more groups and resources available to parents,” she explains. “50% of babies born with Down Syndrome don’t see any structural abnormalities or heart defects.”

Dr. Varrey emphasizes that, regardless of the genetic test outcome, the staff at GBMC is there to walk parents through their next steps.

“We’re very available and accessible. Parents don’t have to spend a long time worrying because we’ll get back to them in a few hours. Our top priority is communicating with our patients.”