Who: Women who have an increased risk of certain birth defects or malformations in the fetus. 

Why: To test for birth defects and certain other conditions.

When: Usually between 15 and 20 weeks of pregnancy.

How: Using ultrasound as a guide, the health care provider inserts a thin needle through the mother’s abdomen and uterus. A small amount of amniotic fluid (the fluid that surrounds the baby) is removed and tested.

Risks: A small risk of miscarriage (1 in 200 or less). Some women have cramping, spotting or leaking of amniotic fluid after the procedure. Serious complications are uncommon.

August 2005