Show
Amniocentesis is a procedure used to take out a small sample of the amniotic fluid for testing. This is the fluid that surrounds the fetus in a pregnant woman. Amniotic fluid is a clear, pale yellow fluid that:
Along with various enzymes, proteins, hormones, and other substances, the amniotic fluid contains cells shed by the fetus. These cells have genetic information that can be used to diagnose genetic disorders and open neural tube defects (ONTDs), such as spina bifida. Testing may also be done to check for inherited gene defects and metabolic disorders based on the family history. Amniotic fluid also contains other substances that give information about the fetus. This procedure may be done in late pregnancy to check fetal well-being and diagnose fetal health problems, such as infection. If a baby is expected to be delivered early, amniocentesis may be done to check for fetal lung maturity. The fluid is sent to a lab so that the cells can grow and be analyzed. Results are most often ready in about 10 days to 14 days, depending on the lab. Results from fetal lung maturity tests are ready within a few hours.
An amniocentesis is offered to women between the 15th and 20th weeks of pregnancy who are at greater risk for birth defects. It may also be used to follow-up when an earlier test suggests a problem. Some conditions where an amniocentesis may be used for genetic and chromosome testing in the second trimester of pregnancy include:
Amniocentesis may be used in the third trimester of pregnancy to check for:
Your healthcare provider may have other reasons to recommend an amniocentesis. What are the risks of an amniocentesis?Some complications of an amniocentesis may include:
The risk of miscarriage is considered less than 1% after an amniocentesis in the second trimester of pregnancy. This is only slightly higher than the normal risk of miscarriage at this time in pregnancy. Certain factors or conditions may interfere with an amniocentesis. These factors include:
You may have other risks, depending on your condition. Be sure to discuss any concerns with your healthcare provider before the procedure. How do I get ready for an amniocentesis?
What happens during an amniocentesis?An amniocentesis may be done on an outpatient basis or during a hospital stay. Procedures may vary depending on your condition and your doctor's practices. Generally, an amniocentesis follows this process:
What happens after an amniocentesis?You and your fetus will be monitored for a time after the procedure. Your vital signs and the fetal heart rate will be checked regularly for an hour or longer. The amniotic fluid sample will be sent to a genetics lab. Alpha-fetoprotein, a protein made by the fetus and present in the fluid, may be measured to rule out an open neural tube defect, such as spina bifida. Testing may also be done for other substances related to metabolic or genetic conditions. Depending on test results, counseling with a genetics specialist may be advised. You may feel some cramping during or after the procedure. If you feel lightheaded, dizzy, or nauseated, tell the nurse. You may be told to rest on your left side. After the test, rest at home and avoid strenuous activities for at least 24 hours, or as directed by your healthcare provider. Tell your healthcare provider if you have any of the following:
Your healthcare provider may give you other instructions after the procedure, depending on your situation. Next stepsBefore you agree to the test or the procedure make sure you know:
Amniocentesis is a relatively simple, safe, and accurate diagnostic tool which is being performed with increased frequency in local hospitals. The maternity nurse has a responsibility to know the clinical applications, the role of the nurse during the procedure, and the potential risks associated with amniocentesis. To read this article in full you will need to make a payment DOI: https://doi.org/10.1111/j.1552-6909.1978.tb00770.x © 1978 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved. |