When it comes to genetic testing for potential parents, “You have options,” says Dr. Susan Klugman, an OB/GYN and geneticist from the American College of Medical Genetics and Genomics. The sooner potential parents take action, the more options they have.
Carrier Screening
The first action is a carrier screening. Using a blood or tissue sample, this screening detects whether a parent-to-be carries genetic mutations associated with disorders such as cystic fibrosis, sickle cell anemia, or Tay-Sachs disease. Because these are “recessive disorders,” if both parents are carriers for the same genetic disorder, there is a 1 in 4 chance that the fetus would be affected.
“The optimal time to consider a carrier screening is before embarking on a pregnancy,” says Dr. Klugman. A “carrier couple” can decide whether they want to try to become pregnant with this 1 in 4 risk. Or they can explore other options for becoming parents, such as adoption or in vitro fertilization, which allows multiple embryos from the same egg and sperm to be screened, ensuring that only unaffected embryos are implanted into the mother’s uterus.
Prenatal Genetic Screening Test
The next action parents can take is a prenatal genetic screening test, which is part of first-trimester, second-trimester, and third-trimester screenings. This uses a sample of the pregnant woman’s blood as well as ultrasound results to screen the fetus for aneuploidy, an abnormal number of chromosomes that can cause Down Syndrome and other disorders, as well as certain defects of the brain, spine, heart, facial features, and abdomen. Like a carrier screening, this test identifies the risk of certain disorders, but not the disorders themselves.
Prenatal Diagnostic Test
A prenatal diagnostic test, such as amniocentesis, can detect whether a fetus is actually affected by a genetic disorder. If an abnormality is detected in time, parents-to-be can decide whether to continue the pregnancy. Or they can coordinate prenatal monitoring and delivery at a center specializing in high-risk pregnancies.
Though genetic testing cannot predict all possible complications in a pregnancy, it gives potential parents crucial information. “Make sure you understand the screening or test you’re undertaking, and ask your doctor,” Dr. Klugman advises — the sooner the better.