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.
Amniocentesis involves passing a thin needle into the uterus to remove a small volume of amniotic fluid. The needle is carefully observed using an 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 heartbeat is normal.
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, or loss of fluid from your vagina, or if you develop a temperature, please seek medical advice.
The results for Down’s syndrome and other major chromosomal defects are usually available within 3 days. The results for rare defects take 2 weeks. As soon as we get the results, we will call you to let you know.
The risk of miscarriage due to amniocentesis is about 1% and this is the same as the risk from chorion villus sampling. If you were to miscarry due to the test, this would 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.
