[Prenatal diagnosis of genetic defects from the amniotic fluid. Report of experiences].

42 pregnancies were monitored by transabdominal amniocentesis followed by karyotyping. Biochemical assays of cultured amniotic fluid cells, 50 analysis of alpha1-fetoprotein and estimations of the number of y-bodies in the amniotic fluid cells was also made. One chromosomal aberration (47, XY, + 18) was found in 13 pregnancies tested because of advanced maternal age. In 6 pregnancies with a recurrence risk of Down's Syndrom, one fetus with abnormal karyotype (46, XY, 5p-) was detected.