AMNIOCENTESIS is a procedure to diagnose abnormalities of the fetus.

It entails removal of fluid from the amniotic sac during pregnancy and is examined in the laboratory.

The best time for amniocentesis is between the 15th and 18th weeks of pregnancy as at this time there is ample fluid, and also enough time to terminate the pregnancy if the baby has some abnormality.

Amniocentesis is often done for one or more of the following reasons:

  • Mother is over 35 years old as risk of abnormalities in the baby increases.
  • Either parent has a chromosome abnormality.
  • Mother has had a child with chromosome abnormality, such as Down's syndrome.
  • Mother carries a sex-linked abnormality, and the unborn child's sex must be determined.
  • Unborn child's maturity or other conditions must be determined late in pregnancy.

Amniocentesis is usually performed in a hospital on outpatient basis under local anesthesia. Sedatives and pain relievers are not used, to ensure the unborn child's safety.


  • A local anesthetic is injected into the abdominal wall.
  • A needle is inserted through the abdomen into the uterus, guided by Ultrasonography. Needle causes temporary pain, but should not hurt more than any injection.
  • A small amount of amniotic fluid is removed and the needle removed.


  • Excessive bleeding and Surgical-wound infection.
  • Unwanted abortion triggered by procedure in 1 out of 100 to 150 cases.


More than 95% of amniocentesis tests indicate no abnormalities. Some couples at high risk want the surgery done to reduce their anxiety during pregnancy. However, normal amniocentesis results cannot guarantee a child without defects. At present there are no tests for ALL abnormalities.


  • Nausea and vomiting.
  • Pain in the lower abdomen or shoulder
  • Vaginal bleeding.
  • Signs of infection: headache, muscle aches, dizziness or a general ill feeling and fever.