Genetic counseling before prenatal diagnosis for advanced maternal age: an important medical safeguard.

Genetic counseling before amniocentesis has been advocated by many geneticists with little evidence to support their contention. Records of patients referred exclusively for advanced maternal age were evaluated for additional diagnostic information obtained from the genetic counseling process that could place these patients at additional risks for previously unsuspected fetal abnormalities. A significant number of patients (43.3%) were at additional risk or had significant concerns regarding one or more hereditary or congenital disorders requiring extensive genetic counseling. The results of the present study provide a scientific basis for the consideration of genetic counseling as a standard part of all prenatal diagnostic procedures.