An amniocentesis is usually a safe and effective way to help find out if there is a problem with your pregnancy.

What is an amniocentesis?

An amniocentesis involves using a needle to remove some of the amniotic fluid that surrounds your baby in your uterus (womb). It is usually performed from 15 weeks of your pregnancy.
An amniocentesis can help find out if your baby has one of the following problems.
  • A chromosome disorder such as Down syndrome
  • A genetic or hereditary disease such as cystic fibrosis or sickle cell anaemia
  • A neural tube defect such as spina bifida
  • A Rhesus problem, which could cause your baby to develop anaemia
However, an amniocentesis does not cover all possible problems.
In the later stages of pregnancy, an amniocentesis can show if you have an infection. It can also help find out how mature your baby’s lungs are, in case you need an early delivery or are in premature labour.

Are there any alternatives to an amniocentesis?

Chorionic villus sampling is a procedure that involves removing small pieces of the placenta and can be performed between 11 and 13 weeks.
It is possible to have a detailed scan or a blood test but these tests can show only if your baby may have a problem.

AmniocentesisWhat does the procedure involve?

Removing the fluid usually takes about 30 seconds.
Your obstetrician will insert the needle in your skin, through your abdominal wall and into your womb (see figure 1). They will remove about 15mls of fluid (1 tablespoon).

What complications can happen?

  • Miscarriage
  • Vaginal spotting or bleeding
  • Premature rupture of your membranes
  • Infection in your womb
  • Discomfort or cramping
  • Injury to your baby
  • Failure to get the fluid at the first attempt
  • Failed culture
  • Uncertain result
  • Removing blood-stained fluid

How soon will I recover?

Your baby’s heartbeat will be monitored for a while and then you will be able to go home.
Rest for the next two days. Most results of an amniocentesis are normal.


Author: Mr Andrew Woods MBBS MRCOG FRANZCOG
Illustrations: Medical Illustration Copyright © 2012 Nucleus Medical Art. All rights reserved.

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Last updated: June 2015

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