Incidence of fetal chromosomal aberration in prenatal cytogenetic examination

One thousand forty-seven fetal samples were obtained from women who received the prenatal cytogenetic examination for different reasons. In this study, the incidence of fetal chromosomal aberration related to each reason was analyzed. The incidence of de novo chromosomal aberration in the fetuses of the higher maternal age group was 1.5% (8/525: 4 cases of 21-trisomy, 2 cases of 18-trisomy and 2 cases of 47,XXY). The incidence in the group of women who had borne (a) chromosomally abnormal child(ren) was 0.5% (1/202). There was no repeat of 21-trisomy, 18-trisomy or 13-trisomy in this study. The incidence in the group of women who had ultrasonographic abnormalities was 16.9% (26/154). In this study, abnormal amniotic fluid volume, intrauterine growth retardation, malformation, hydrops fetalis, intestinal obstruction, omphalocele, single cord artery and cerebellar hypoplasia were related to chromosomal aberrations. The incidence in the group of women whose husband or herself was cytogenetically abnormal was 40.0% (26/65). This high value indicated that parental translocation and inversion are easily transmitted to their offspring.