Amniocentesis

Amniocentesis is a procedure used to obtain a small sample of the amniotic fluid that surrounds the fetus during pregnancy. Amniotic fluid is a clear, pale yellow fluid made by the fetus. The fluid protects the fetus from injury and helps to regulate the temperature of the fetus. In addition to various enzymes, proteins, hormones, and other substances, the amniotic fluid contains cells shed by the fetus. These cells contain genetic information that can be used to diagnose chromosomal disorders and open neural tube defects (ONTDs), such as spina bifida. Testing may be available for other genetic defects and metabolic disorders depending on the family history and availability of lab testing at the time of the procedure. Amniotic fluid also contains other substances that provide information about certain conditions. An amniocentesis may be performed in late pregnancy to check fetal well-being and diagnose fetal conditions, such as infection. An amniocentesis may be performed to check for fetal lung maturity if a baby is expected to be delivered early. Specific substances present in the amniotic fluid can be measured or tested for these conditions.