The relevance of pre-amniocentesis pedigree analysis and genetic counseling.

Prenatal diagnosis by amniocentesis in the second trimester of pregnancy has become widely accepted, and the demand for the procedure is increasing exponentially. It is important to reevaluate critically the time and effort spent obtaining a detailed pedigree analysis and family history prior to amniocentesis. Two hundred unselected consecutive cases of women undergoing amniocentesis because of advanced maternal age were studied. One woman had a brother with Duchenne muscular dystrophy and she was found by CPK testing to be a carrier. The prenatal diagnosis revealed that she was carrying a male fetus with a 50% chance of being affected, and the couple decided to have a termination of the pregnancy. A variety of other familial disorders and teratogenic exposures which were found in the studied 200 families were further explored through genetic counseling. Additional reasons for the individual pre-amniocentesis counseling include reducing anxiety and responding to specific psychosocial aspects of the prenatal diagnosis procedure in particular families.