Amniocentesis: Brief Version

What is amniocentesis?

Amniocentesis is a test done to check the health of your baby while you are pregnant. Your baby grows in your uterus, in a special bag of waters called the amniotic sac. The fluid in this sac is tested to check for different kinds of problems.

When is it used?

This test can help check for some problems with the baby. This test may be done if:

• You are 35 years old or older.
• Other tests show there might be a problem.
• You have had an earlier pregnancy or child with a birth defect.
• You or your baby's father has a history of genetic problems in your families.
• You were exposed to harmful drugs or radiation while pregnant.
• You have had miscarriages.

The test may be done to check for problems with the baby’s genes when you are 15 to 18 weeks pregnant. If the baby may need to be born early, the test may be done later in pregnancy to see if the baby’s lungs have developed enough. The test may also be used to check for an infection in the amniotic fluid.

How do I get ready for this test?

Follow the instructions your healthcare provider gives you.

What happens during the test?

Your healthcare provider cleans your belly and may numb the skin. A long needle is put through your belly into the uterus. You may feel a little discomfort. Your provider uses ultrasound to help guide the needle away from the baby and to where the most fluid is. He or she takes some fluid out and sends it to the lab.

What happens afterwards?

You and the baby will be watched for a little while. Then you can go home. You should rest for about 24 hours afterwards.

How long does it take to hear the results of the test?

• You should be able to get results of genetic tests in about 1 to 2 weeks.
• If your baby's lungs are being tested, you should hear within a day.
• A check for infection may take a few hours to a few days. It depends on what tests the lab is doing.

How does this test help?

It can help check for:

• Some birth defects such as Down syndrome or spina bifida.
• Infection in the amniotic fluid.
• How well the baby's lungs will work after delivery.
• Certain types of substances that might hurt the baby.
• The sex of the baby, when necessary.

What are the problems with having this test done?

Most women don’t have any problems from this test. Problems that can happen are:

• Bleeding.
• Infections.
• Harm to the baby, placenta, or umbilical cord from the needle.
• Early breaking of the bag of waters.
• Early labor or contractions.
• Miscarriage.

What should I watch for after the test?

Call your healthcare provider right away if:

• You start having contractions or cramps that are getting worse. (It’s normal to have a little cramping for 4 to 6 hours after the test.)
• You have bleeding or other leaking from the vagina that does not stop.
• You have a fever over 100°F (37.8°C).
• You have any changes that worry you.

Call your provider during office hours if:

• You have questions about the test or its results.
• You want to make another appointment.