Because the technology and information is changing so quickly, prenatal testing can be confusing for many expecting parents, and even for doctors. Prenatal tests are medical tests that help healthcare professionals check on how both you and your baby are doing throughout your pregnancy. Some prenatal tests screen for health conditions in the baby.
Most types of prenatal screening tests are routinely provided to all expecting parents by their obstetric care team to get a better sense of risk, even those with no family history of genetic conditions. Diagnostic testing, on the other hand, may be recommended if you and your baby already have a known or increased risk for certain complications.
Prenatal screening tests are designed to determine the likelihood of your baby facing a diagnosis of a specific genetic condition or birth defect. Screening will not tell you whether their baby definitely has a condition; screening only lets you know whether further testing is needed to determine if your baby has a condition. Prenatal screening is a part of standard prenatal care during pregnancy, but it is your decision to choose prenatal screening for you and your baby.
Prenatal screening may include:
- First trimester screening
- First trimester ultrasound
- Maternal blood screen (quad screen)
- Second trimester ultrasound
- Glucose screening
- Strep B test
Non-invasive prenatal testing (NIPT) (also known as cell-free fetal DNA testing) is another option for accurately and safely screening the risk of your baby developing a condition. Using a blood sample from the mother, NIPT detects tiny pieces of the baby's DNA circulating in the mother’s bloodstream.
Prenatal diagnostic tests are available to all pregnant women, but may be recommended by your provider or genetic counselor, if you are at higher risk of having a baby with specific genetic conditions or birth defects.
Some risk factors may include:
- If you have had a previously affected pregnancy
- If you have a personal or family history of a condition
- If you screen positive on prenatal screening tests
- If you are older than 35 years of age
- If you and your partner are known carriers for genetic conditions
Diagnostic tests are the only way to confirm a genetic condition in a developing baby. Unlike prenatal screening, diagnostic testing can carry certain risks, such as miscarriage and other pregnancy complications, in fewer than 1% of women. The diagnostic tests currently available are chorionic villi sampling (CVS), performed at 10-13 weeks and amniocentesis (amnio), performed between 15-20 weeks.
Blood pressure checks, urine tests, blood tests, and weight checks are other routine procedures that might are performed several times throughout your pregnancy to ensure that both you and baby are healthy.
The decision to undergo prenatal testing is a personal one. If you’re pregnant and trying to determine if prenatal testing is right for you and your baby, talk to your doctor, midwife, genetic counselor, and/or other healthcare specialist about your options.