Background:
To determine the incidence of chromosomal abnormality of fetal loss during pregnancy and to evaluate the reliable method of determining the karyotype of conceptus and fetus.
Methods:
Between January 1991 and August 1994, cytogenetic analysis of G-banded metaphase were performed on 125 cases of passed conceptus(97 cases) and chorionic villus specimen(CVS: nine cases0 and fetal tissue(19 cases) by tissue culture methods
after
mechanical and enzymatic digestion.
Results:
thirty-eight cases930.4%) of karyotypes were abnormal. Of the 38 abnormal karyotpes, 13(34.2%) were autosomal trisomies, 11(29.0%) were monosomy-X, nine(26.7%) were triploidy, and five(13.1%) were tranlocations and others. In CVSs and fetal
tissues,
the incidence of abnormal karyotype was 50% and in normal karyotypes male: female ratio was 0.75. In contrast, in passed conceptus the incidence of abnormal karyotypes was 24.7% and in normal karyotypes male: female ratio was 0.30, and these
findings
suggested the possibility of contamination of maternal cell during preparation of specimen. Mean maternal ages of fetus with trisomy, triploidy and monosomy were 30.0, 30.1 and 29.4 yearsold, respectively, but there was no significant difference.
Correlation between karyotype and gestational age the time of fetal loss showed no concordance with other previous reports due to low numbers of cases.
Conclusions:
Chromosomal abnormality was the major cause of fetal loss during pregnancy, and for the accurate cytogenetic analysis the selection of proper specimen was important, such as CVS and fetal tissue instead of passed conceptus.
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