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Amniocentesis is a prenatal test that helps you learn if your baby has genetic problems. The test is most often done between 15 and 20 weeks of pregnancy. Talk with your healthcare provider to see if amniocentesis is right for you, and if the risks outweigh the benefits.

Should you have amniocentesis?

If your baby has a higher-than-normal chance of birth defects or other problems, you may want to have this test. These risk factors can increase chances of your baby having health problems:

  • You’re 35 or older.

  • There’s a history of inherited (genetic) problems in your family.

  • Other tests have shown that the baby may have health problems.

How is amniocentesis done?

  • First, the baby is located with ultrasound (sound waves that make an image on a screen).

  • A thin needle is then put into your belly. The healthcare provider keeps the needle from touching the baby by watching the screen.

  • The needle is used to remove a small amount of fluid from your uterus. Your body will make more fluid to replace what was taken.

  • You can go home right after the test. But you may need to take it easy for a day or so.

    Side view of pregnant woman showing fetus, ultrasound probe, and needle taking sample of amniotic fluid for amniocentesis.

What are the possible risks?

This test is considered safe. But there are some possible risks. These include:

  • Cramping, spotting, or leaking amniotic fluid

  • Infection in the uterus

  • Pregnancy loss (miscarriage)—this is rare, and occurs in about 1 in 200 to 1 in 400 cases

  • The needle coming into contact with the baby—this is rare

When to call your healthcare provider

Call your healthcare provider right away if you have:

  • Severe pain or cramping

  • Vaginal bleeding (spotting)

  • Fever or chills

  • Fluid leaking from your vagina

Getting test results

You’ll get your test results in 2 weeks. Most results are normal. Even if yours aren’t, it doesn’t always mean there’s a problem. But this will depend on what your healthcare provider is looking for with amniocentesis. You and your provider can talk about other tests or special care you may want.

Online Medical Reviewer: Donna Freeborn PhD CNM FNP
Online Medical Reviewer: Heather M Trevino BSN RNC
Online Medical Reviewer: Irina Burd MD PhD
Date Last Reviewed: 7/1/2022
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