First Time User? Sign Up Now
First Time User? Enroll now.
Home > Health Library > Amniocentesis
Amniocentesis is a test to study the liquid (amniotic fluid) that surrounds a baby. Amniotic fluid contains cells and other substances that can give clues about a baby's health. Amniocentesis can be done after about the 15th week of pregnancy, when there is enough amniotic fluid for testing.
Amniocentesis is done by putting a needle through the belly into the uterus. About 2 Tbsp (30 mL) of the amniotic fluid is collected and examined in a lab. The fluid sample can be examined for:
Levels of certain substances in the fluid sample, such as alpha-fetoprotein, can also be checked. Some abnormal levels may mean there is a problem with the development of the brain and nerves.
Amniocentesis is usually done between weeks 15 and 20 of the pregnancy for genetic testing. It can be done later, during the third trimester of pregnancy, to find out how mature the baby's lungs are.
Current as of:
September 5, 2018
Medical Review:Sarah A. Marshall, MD - Family Medicine & Adam Husney, MD - Family Medicine & Kirtly Jones, MD - Obstetrics and Gynecology, Reproductive Endocrinology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2018 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
UNC Medical Center
101 Manning Drive
Chapel Hill, NC 27514
UNC Health Care Citrix
UNC Medical Center Intranet
Copyright 2019 UNC Health Care. All rights reserved.