Compare the benefits and risks associated with amniocentesis and chorionic villus sampling.

Concepts to Consider: Amniocentesis involves collecting a sample of fetal cells from the amniotic fluid that surrounds the fetus. The karyotype of these cells can then be examined for chromosomal defects. Chorionic villus sampling can be used effectively earlier in pregnancy than amniocentesis; however, it is associated with a slightly greater risk of miscarriage. Also, because the conditions diagnosed using these procedures are incurable, there may be both psychological and physical benefits to having the information available earlier in the pregnancy if abortion is going to be considered.