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  • Cynthia M. Johnson, MA
Publication Type:




Amniocentesis is a test that may be done during pregnancy. It removes a small amount of the fluid that surrounds the fetus for testing.


Amniocentesishttp://services.epnet.com/getimage.aspx?imageiid=73337333si55550976.jpgsi55550976.jpgNULLjpgsi55550976.jpgNULL\\hgfiler01a\intellect\images\si55550976.jpgNULL28NULL2008-11-07284390Copyright © Nucleus Medical Media, Inc.

Reasons for Procedure

This procedure is done on people who are at risk for problems after 15 weeks of pregnancy. It tests cells in the fluid to look for signs of:

This test may also be done to make sure the fetus' lungs are growing as expected.

Possible Complications

Problems are rare, but all procedures have some risk. The doctor will go over some problems that could happen, such as:

  • Bleeding, cramping, and fluid leaking from the vagina
  • Infection
  • Mixing of blood if the mother and baby have different blood types
  • Need for repeat testing
  • Harm to the fetus by the needle—rare
  • Miscarriage—rare

Things that may raise the risk of problems are:

  • Obesity in the mother
  • Past abdominal surgery

What to Expect

Problems to Look Out For

Call the doctor if you are not getting better or you have:

  • Signs of infection, such as fever and chills
  • Nausea or vomiting
  • Pain or cramping in the belly
  • Blood or fluid leaking from the vagina
  • Redness, swelling, increasing pain, excessive bleeding, or discharge from the needle site
  • New or worsening symptoms

If you think you have an emergency, call for medical help right away.

Prior to Procedure

The healthcare team may meet with you to talk about:

  • Anesthesia options
  • Any allergies you may have
  • Current medicines, herbs, and supplements that you take and whether you need to stop taking them before the procedure
  • Whether you need a ride to and from the procedure




  • Chorionic villus sampling: CVS. American College of Obstetricians and Gynecologists website. Available at: http://americanpregnancy.org/prenatal-testing/chorionic-villus-sampling.
  • Hemolytic disease of the fetus and newborn (HDFN). EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hemolytic-disease-of-the-fetus-and-newborn-hdfn.
  • Routine prenatal care. EBSCO DynaMed website. Available at: https://www.dynamed.com/management/routine-prenatal-care-36.


  • Elizabeth Margaret Prusak, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.