For Patients


What is Amniocentesis?
  • Amniocentesis involves the examination of cells in the fluid from around the fetus (amniotic fluid).
  • The cells in the amniotic fluid originate from the baby and so the chromosomes present in these cells are the same as those of the baby.
How is amniocentesis done?
  • Amniocentesis involves passing a thin needle into the uterus in order to remove a small volume of amniotic fluid. The needle is carefully observed using ultrasound scan.
  • The fluid is fetal urine and the amount removed by amniocentesis reaccumulates within a few hours.
  • The procedure lasts 1 minute and afterwards we check that the fetal heart beat is normal.
What should I expect after amniocentesis?
  • For the first couple of days you may experience some abdominal discomfort or period-like pain. You may find it helpful to take simple painkillers like paracetamol.
  • If there is a lot of pain, bleeding, loss of fluid from your vagina or if you develop a temperature please seek medical advice.
When can I expect to get the results?
  • The rapid results for Down's syndrome and other major chromosomal defects are usually available within 3 days (FISH or PCR). The results for rare defects and the full culture can take 2 weeks. As soon as we get the results, we will call you to let you know.
What are the risks associated with amniocentesis?
  • The risk of miscarriage due to amniocentesis is about 0.6% and this is the same as the risk from chorion villus sampling. If you were to miscarry due to the test, this would usually happen within the next five days.
  • Some studies have shown that when amniocentesis is performed before 16 weeks there is a small risk of the baby developing club feet. To avoid this risk we never perform amniocentesis before 16 weeks.