The watery fluid surrounding the fetus during pregnancy is called amniotic fluid. It is encased in the amniotic sac and keeps the baby warm and cushioned from the outside environment. It also contains valuable information about the baby’s health and development. Your OB-GYN can test the amniotic fluid with a procedure called an amniocentesis.
An amniocentesis can be performed during a prenatal appointment, usually between the 15th and 18th weeks of pregnancy. It involves withdrawing a small sample of amniotic fluid through a very thin needle inserted through the uterine and abdominal walls. The needle is carefully guided using an ultrasound to avoid the developing fetus.
The amniotic fluid sample is then sent to a lab for testing. Typically, the doctor will order specific tests depending on the rationale for the amniocentesis and the baby’s genetic risk for certain conditions.
What Can an Amniocentesis Test For?
An amniocentesis is typically performed to test for certain birth defects and genetic conditions. Usually, an amniocentesis is only performed if there is reason to suspect the baby is at risk, such as a family history of genetic diseases or advanced maternal age. An amniocentesis might be performed if the mother had a previous pregnancy with a birth defect or if an ultrasound exam showed abnormal results.
Amniocentesis can test for multiple conditions including:
- Down syndrome
- Cystic Fibrosis
- Sickle cell anemia
- Tay-Sachs disease
- Muscular dystrophy
- Spina bifida
An amniocentesis is also sometimes performed in the third trimester to check on the baby’s lung development if an early delivery is recommended. The baby’s gender can also be confirmed. Test results are available in within 2-3 weeks.
An amniocentesis carries a small risk of miscarriage, which occurs in about 1 in 200-400 procedures. There is some risk of injury, infection, and preterm labor, but these complications are exceedingly rare.
The procedure may be uncomfortable. Typically, a local anesthetic is administered to numb the area where the needle will be inserted. Even so, you may feel cramping and pain during and for a couple hours after the procedure. It’s recommended that you go home after the procedure and rest. You should avoid exercise, sexual intercourse, and lifting anything heavier than 15 pounds.
If you develop a fever or experience vaginal bleeding, discharge, or severe pain during your recovery, please call your OB-GYN immediately. It may be a sign of infection or another complication.