Genetic screening is a process used to determine a child's risk of inheriting certain diseases or birth defects from his or her parents. Couples planning to have a baby might be concerned about illnesses in the family that their child could inherit. The best time to have a genetic screening done is before you get pregnant, but it can also be done during your first prenatal visit or later in your pregnancy.

Common reasons for genetic screening include:

  • You will be 35 years old or older when you deliver your baby.
  • You already gave birth to a child with a hereditary disease or birth defect.
  • You have had stillbirths or several miscarriages.
  • You have an abnormality such as too much or too little serum alpha fetoprotein (AFP).
  • You have a family history of the certain conditions, such as:
    • Tay-Sach's disease is a brain disorder, which is more common in people of Eastern European (Ashkenazi) Jewish descent, that causes early death.
    • Thalassemia causes abnormal red blood cells. The condition is more common in people from southeast Asia, China, and Mediterranean countries, such as Greece and Italy.
    • Hemophilia is a blood clotting disorder.
    • Cystic fibrosis, caused by two defected genes, affects the lungs and pancreas.
    • Sickle cell anemia, which is more common in African Americans of sub-Saharan origin, affects the red blood cells.