How Are Birth Defects Diagnosed?

Many birth defects can be diagnosed during pregnancy, depending on the particular type of birth defect. Prenatal ultrasounds can be used to diagnose certain birth defects in utero. More in-depth screening options, such as blood tests and amniocentesis (taking a sample of the amniotic fluid), may also be done. These tests are usually offered to women who have higher risk pregnancies due to family history, advanced maternal age, or other known factors.

Prenatal tests can help determine whether the mother has an infection or other condition that’s harmful to the baby. A physical examination and hearing test may also be used to diagnose birth defects after the baby is born. A blood test called the newborn screen can help diagnose some birth defects shortly after birth, before symptoms occur.

It’s important to know that prenatal screening doesn’t always find defects when they’re present. A screening test can also falsely identify defects. Most birth defects can be diagnosed with certainty after birth.