During pregnancy, babies survive in amniotic fluid, a substance much like water. Amniotic fluid contains live fetal cells and other substances that can provide important information about a baby’s health before birth. Amniocentesis is a prenatal test in which a small amount of amniotic fluid is extracted from the amniotic sac surrounding a baby in the uterus for testing. Less than an ounce of fluid is removed, and that fluid is sent to a lab for analysis. Different tests can be performed on the sample of amniotic fluid and can give doctors a variety of information regarding a baby’s healthy and development.
During an amniocentesis, a small area of the abdomen will be cleansed with an antiseptic to prepare for the procedure. A local anesthetic is typically given to reduce any discomfort associated with the amniocentesis. The doctor will use an ultrasound machine to locate the position of the baby and the placenta. The ultrasound guidance will be handed over to an ultrasound technician who will continually monitor the position of the baby while the doctor performs the amniocentesis. With this guidance, the doctor will insert a thin, hollow needle through the abdomen and uterus into the amniotic sac as far away from the baby as possible. A small amount of fluid will be removed through the needle and sent away for analysis. Many women feel menstrual-like cramps or discomfort during the procedure and up to a few hours afterward. Rest and acetaminophen are generally recommended to continue to relieve any discomfort.
An amniocentesis is not given nor recommended for every woman. Because of a small risk to the mother and baby, only those with significant risk for genetic diseases are usually offered an amniocentesis. An abnormal ultrasound, family history of birth defects, and a woman being over the age of 35 at delivery are included in the “significant risk” category.
Amniocentesis can detect certain conditions and birth defects and can also be done to determine if a baby’s lungs are mature enough for delivery if a mother is at risk for a premature birth. The accuracy of amniocentesis is over 99%, and is used by doctors and prenatal specialists to learn as much as possible about a baby with any prenatal risk.
Posted on behalf of Carlos Alarcon, M.D., Marietta OB-GYN Affiliates, P.A.