This article is from the Pregnancy Screening FAQ, by Lynn Gazis-Sax (email@example.com) with numerous contributions by others.
Amniocentesis, or amnio, is a prenatal test in which a needle is inserted
into a woman's abdomen to remove a portion of the amniotic fluid. This is
usually done in conjunction with an ultrasound test so that the doctor can
see where he is putting the needle to avoid harming the fetus. By
performing biochemical tests and by examining the fetal cells in this
amniotic fluid, it is possible to detect certain disabilities.