CHROMOSOMAL-ANOMALIES IN ABNORMAL HUMAN PREGNANCIES

Objective: The aim of this study was to describe the cytogenetic obser vations on abnormal human pregnancies (anembryonic pregnancy, early fe tal loss, and hydatidiform moles), and to detect the most frequent or typical chromosomal aberration for anembryonic pregnancy and early fet al loss. Study Design: Abnormal pregnancies were divided into three cl inical and morphological groups: (a) anembryonic pregnancy; (b) early fetal loss, and (c) hydatidiform mole. Of the 119 karyotyped tissue sa mples, 42 (35%) were from anembryonic pregnancies, 64 (54%) from early fetal losses, and 13 (11%)were from hydatidiform moles (6 complete an d 7 partial moles). Long-term cultures of chorionic villi and GTG-band ing techniques were used for chromosome analysis. Results and Conclusi on: The overall frequency of chromosome anomalies among the 119 karyot yped spontaneous abortions was found to be 37.8%. Trisomy (double tris omy included) accounted for 35.6% of all aberrations, followed by poly ploidy (33.3%), mosaicism (11.1%), tructural abnormalities (4.4%), and monosomy X (2.2%). Although the difference was not statistically sign ificant, single trisomy was the predominant chromosome abnormality fou nd in anembryonic pregnancies (64.3%) while in cases of early fetal lo ss, trisomy (double trisomy included) (38.9%) and triploidy (27.8%) we re quite frequently present. The frequency of triploidy among all chro mosomal abnormalities was 28.9%, and 53.8% of them were found in parti al hydatidiform mole. The rest of them were almost exclusively found i n early fetal losses. Complete hydatidiform moles (androgenetic in ori gin) were present in 13.3% of all aberrations, of which 83.3% had a 46 ,XX, and the rest of them had a 46,XY karyotype.