Amniocentesis is a prenatal test, in which some amniotic fluid is taken from the uterus of pregnant women for examination. This test determines whether the baby has a chromosomal defect, such as Down syndrome. Also can be determined whether the child has a birth defect, such as spina bifida.
Amniocentesis is performed when a woman is at increased risk of having a child with a birth defect. Amniocentesis is done around the sixteenth week of pregnancy.
The amniotic fluid contains cells of the unborn child. These cells are taken via a puncture and then grown in a culture, after which the chromosome pattern can be analyzed in specialized laboratories. In addition to the body cells, the amount of alpha-fetoprotein in the amniotic fluid itself is also examined. An increased amount of this substance is an indication of spina bifida or another physical disease.
A thin needle is inserted through the abdominal skin and abdominal wall, guided by ultrasound, into the amniotic fluid. The position of the child is taken into account. Then the gynaecologist sucks up about twenty milliliters of amniotic fluid. This is less than ten percent of the total amount of amniotic fluid. After the examination, some women have a cramping sensation in the lower abdomen for a short time.
The examination takes approximately 10 minutes.