Prenatal diagnosis of a number of severe is possible by amniocentesis in the 14th pregnancy and the subsequent analysis of genetic disorders 16th week of cultured amniotic fluid cells or amniotic fluid supernatant. Pareuts at risk for a child with a chromosomal disorder, a roetabolie disease, an X-linked disease ar a neural tube defect may use this new tool in genetic counseling to limit their further offspring to unaffected children by requesting terminatien of a pregnancy when a fetal abnormality has been detected or made likely. This thesis describes the clinical aspects of prenatal diagnosis in 254 pregnancies with an elevated genetic risk. It contains subsequently the indications for prenatal diagnosis, the technique and complications of amniocentesis in early pregnancy, the results of prenatal diagnosis, the techniques for terminatien of pregnancy in the secoud trimester and the results of a detailed follow-up study on 58 children born after amniocentesis