Amniocentesis is a test performed during pregnancy that removes a small amount of the fluid surrounding a fetus.
What is amniocentesis?
Amniotic fluid envelops a fetus throughout pregnancy and contains numerous substances that can to provide information about the health of the baby. Amniocentesis the name given to the prenatal test that checks this fluid for and an indication of birth defects if the parents present a significant genetic risk. Amniocentesis boasts an accuracy rate of around 99.4%.
Why consider amniocentesis?
Amniocentesis is recommended for a variety of reasons including:
- Known genetic conditions – women can have a significant risk for genetic diseases because of family history including down syndrome, cystic fibrosis, sickle cell disease and muscular dystrophy
- Previous pregnancy issues – if a prior birth was affected by a neural tube defect or genetic abnormality, a doctor will likely recommend amniocentesis
- Abnormal ultrasounds – the procedure can detect some diseases where the brain and spine fail to develop properly, such as spina bifida
- Geriatric pregnancy – women 35 and older carry a higher risk of chromosomal conditions
The complete anatomical ultrasound performed before the amniocentesis can itself be helpful in identifying issues such as heart defects, infection, lung capacity, cleft lip/palate and club food. It is also the most accurate way to determine the baby’s gender during the pregnancy. Additionally, amniocentesis can drain any excess amniotic fluid that has built up in the uterus.
How is amniocentesis performed?
After a local anesthetic is administered, a small needle is used to enter the uterus through the mother’s abdomen. This usually occurs between the 15th and 18th week of pregnancy. It is guided using an ultrasound until it reaches the sack surrounding the fetus. Less than one ounce of fluid is extracted at a safe distance from the baby and is then sent to a laboratory for genetic analysis that is specific to each case. The results of the amniocentesis are generally available within 2-3 weeks.
After the procedure, it is important for the mother to avoid exercise or strenuous activity. This includes lifting anything over 15 pounds as well as sexual intercourse. These activities may resume a full day after the procedure. If experiencing discomfort, it is acceptable to take over-the-counter pain relievers such as acetaminophen.
What are the risks of amniocentesis?
While amniocentesis can be incredibly useful in certain circumstances, it cannot detect every possible birth defect that could be affecting the child. It also carries some risks for both the mother and the baby. There is a 1 in 200 to 1 in 400 chance that amniocentesis will cause a miscarriage. The procedure also carries the rare risk of infection and premature labor.
Amniocentesis is an optional procedure that will never be forced on a mother. A genetic counseling session will determine if the procedure is warranted and present the possible benefits and risks.