Skip to content

Health & Pregnancy

Font Size


Why It Is Done

Amniocentesis may be done during your second trimester of pregnancy to find certain birth defects.

You may choose to have this test because:

  • Of your age. As you get older, you have a greater chance of having a baby with a birth defect. Many doctors use 35 and older as the age for higher risk.
  • You want to know for sure if your baby has a certain health problem. This may help you decide early whether you want to continue your pregnancy or make plans to care for a sick child.
  • You or the baby's father carries an abnormal gene that is known to cause a disease, such as Tay-Sachs disease, sickle cell anemia, or cystic fibrosis.
  • You or the baby's father has a family history of a genetic disorder or birth defect.
  • Screening tests suggest that your chance of having a baby with a genetic disorder or birth defect is higher than average.

Amniocentesis can tell the gender of your fetus. This is important when you or the father may be able to pass on a disease that occurs mainly in one gender (sex-linked), such as hemophilia or Duchenne muscular dystrophy, both of which occur mainly in males.

Amniocentesis may be done during your third trimester to:

  • See if your fetus's lungs are mature. This may be done when you may need to deliver early because of a problem with the pregnancy.
  • See whether the amniotic fluid is infected (chorioamnionitis).

How To Prepare

You will be asked to empty your bladder just before the test.

You will need to sign a consent form that says you understand the risks of the test and agree to have it done.

Talk to your doctor about any concerns you have about the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

How It Is Done

Amniocentesis camera.gif is done by your obstetrician in his or her office or in the hospital. An overnight stay in the hospital usually is not needed unless problems occur during the test.

WebMD Medical Reference from Healthwise

Last Updated: June 04, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Pregnancy Week-By-Week Newsletter

Delivered right to your inbox, get pictures and facts on
what to expect each week of your pregnancy.

Today on WebMD

hand circling date on calendar
Track your most fertile days.
woman looking at ultrasound
Week-by-week pregnancy guide.
Pretty pregnant woman timing contaction pains
The signs to watch out for.
pregnant woman in hospital
Are there ways to do it naturally?
slideshow fetal development
pregnancy first trimester warning signs
What Causes Bipolar
Woman trying on dress in store
pregnant woman
Close up on eyes of baby breastfeeding
healthtool pregnancy calendar
eddleman prepare your body pregnancy