Amniocentesis refer to the extraction of fluid from the amniotic sac in order to test for chromosomal and genetic defects in the developing fetus.

See also:
"Amniocentesis" is in the UNSPSC Code "42142501"
  Amniocentesis needles

Other definition:
Amniocentesis refers ti prenatal medical procedure that allows the detection of abnormalities (for example, Down syndrome) in the developing fetus. It involves removal and analysis of amniotic fluid from the mother.