The prenatal diagnosis of genetic disorders.

Prenatal diagnosis has proven highly effective in assessing the status of fetuses at risk of all cytogenetic and of several biochemical and structural disorders with genetic etiologies. The original methodology, based on the cytogenetic and biochemical analysis of cultured amniotic fluid cells, has now been complemented by a wide variety of new techniques. These include several methods for fetal visualization (sonography, fetoscopy, x ray), sampling of fetal blood, and analysis of very small quantities of material. Additional approaches, based on these and other technologies, are likely to permit the prenatal diagnosis of an ever increasing number of genetic disorders. At the same time, the number of pregnancies monitored will increase as greater resources become available and as screening programs identify couples at risk of having genetically abnormal children prior to the birth of an affected child. Prenatal diagnosis is already a powerful means of preventing the birth of individuals with significant genetic defects, thereby sparing both individuals and society from the burdens that such disorders produce. In the future, it is likely to be even more effective.