ABSTRACT
OBJECTIVE: Genetic defects of the zygote, such as chromosome aberration, are the most frequent cause of abnormal embryonic development and spontaneous abortion. Recent advances in ultrasonographic technology have allowed documentation of early embryonic growth and development and some studies have suggested that once fetal cardiac activity has been demonstrated at 8-10 weeks of gestation, the subsequent spontaneous abortion rate is reported to be less than 5% of pregnancies. Some authors suggested that, abortions in which fetal cardiac activity was once demonstrated, chromosomal anomalies are considered to play important roles in these abortions. But, other studies failed to reveal any relationship between occurrence of chromosomal abnormalities and ultrasonographic detection of fetal heart activity. The aim of the study was to determine the relationship of ultrasonographic detection of fetal heart activity and the abnormal karyotypes in spontaneous abortions. DESIGN: A 1-year retrospective, study. MATERIALS AND METHODS: 158 pregnancies (129 spontaneous, 29 assisted ovulatory cycles) that aborted in the first trimester between January 1,2001 and December 31, 2001, in Samsung Cheil Hospital had chromosomal analysis performed on the products of conception and had ultrasonographic examination prior to spontaneous abortion. Of these pregnancies 62 were detection of transvaginal ultrasonographic detection of fetal heart activity prior to abortion and 96 were failure to detect fetal heart activity. Fetal tissue was removed by dilatation and curettage. Cytogenetic studies were performed from cultures of dissected chorionic villi and G-sac. And then, we compared the incidence and the characteristics of abnormal karyotypes between fetal heart activity detected group (Group I) and failure to detect fetal heart activity group (Group II) prior to abortion. RESULTS: Of 158 spontaneous abortions who carrying chromosomal analysis, 98 had abnormal karyotypes. (60 trisomies, 11 polyploides, 10 mosaicism, 5 monosomies and 12 structural abnormalities). The overall incidence of chromosomal aberrations in our study group was 62.0% (98/158). Chromosomal aberrations were found in 59.7% (37/62) of abortuses in group I and 63.5% (61/96) in group II and it was insignificant statistically. The frequency of type of abnormal karyotype in both groups (Group I: 25 (40.3%) trisomies, 1 (1.6%) polyploides, 0 (0%) mosaicism, 8 (12.9%) and 3 (4.8%) monosomies, Group II: 35 (36.5%) trisomies, 10 (10.4%) polyploides, 5 (5.2%) mosaicism, 2 (2.1%) monosomies and 9 (9.4%) structural abnormalities) were insignificant statistically. When we stratified both groups and analyzed the abnormal karyotype by maternal age, those were not statistically different in both groups. CONCLUSION: In our study, chromosomal abnormalities in spontaneous abortion did not differ according to ultrasonographic detection of fetal heart activity, and the type of abnormal karyotype were not distributed differently.