Amniocentesis is a test that may be done during pregnancy to check the health of your baby. A very thin needle is used to remove a small amount of fluid from the amniotic sac. The amniotic sac is a thin sac filled with fluid that surrounds the baby. The fluid contains cells that come from the baby, as well as other substances. These cells and substances can be tested in the lab to give information about the health of the baby.
Early in pregnancy the cells can be tested for some genetic problems the baby might have. Your healthcare provider may advise you to have this test at this time if:
When the test is used to check for genetic problems, it is usually done between the 15th and 18th weeks of pregnancy.
The test may be done toward the end of pregnancy to see if the baby's lungs are mature enough for the baby to breathe well after birth. This is sometimes done if you have a high-risk condition and your healthcare provider thinks that it may be best to deliver the baby earlier than your due date.
Amniocentesis can also be used to check for an infection in the amniotic fluid.
You usually do not have to do anything to prepare for an amniocentesis early in pregnancy.
If the procedure is being done near your due date, your healthcare provider may advise you to avoid eating or drinking anything the day of the test.
Follow any other instructions your healthcare provider gives you.
The baby's heart rate is checked before and after the test. Your abdomen is cleaned with a liquid antiseptic solution. It is usually not necessary to use numbing medicine before performing this test.
Your healthcare provider uses ultrasound images to help guide a thin needle through your abdomen, into the uterus, away from the baby, and to the area where the most amniotic fluid is. Like when you have your blood drawn, you may feel some brief and mild discomfort when the needle is inserted into the skin of your abdomen. A small amount of fluid (1 to 2 tablespoons) is withdrawn into a syringe and sent to the lab for tests.
If you are pregnant with more than 1 baby, a sample of fluid may be taken from each baby's amniotic sac. This is done with different needles through your skin.
Your pulse, your blood pressure, and the baby's movements will be watched for a brief time after the test. Then you usually can go home. You should rest for 24 hours after the test.
The results of most of the genetic tests will be available in 1 to 2 weeks. Lung maturity can be determined faster, usually from 6 hours to 1 day. The results of a test for infection may take a few hours. It will take up to a few days if a culture is needed to check for certain bacterial infections.
The overall risk of complications from this procedure is very low. Less than 1 out of 200 women who have the test may develop a problem. Problems that can occur are:
It is important to understand that normal test results cannot guarantee that the baby will be normal. Also, in very rare cases, an abnormal result may not be accurate.
Call your provider right away if:
Call during office hours if: