Chromosomal Anomalies in Abnormal Human Pregnancies

Abstract

The overall frequency of chromosome anomalies among the 119 karyotyped spontaneous abortions was found to be 37.8%. Trisomy (double trisomy included) accounted for 35.6% of all aberrations, followed by polyploidy (33.3%), mosaicism (11.1%), structural abnormalities (4.4%), and monosomy X (2.2%). Although the difference was not statistically significant, single trisomy was the predominant chromosome abnormality found in anembryonic pregnancies (64.3 %) while in cases of early fetal loss, trisomy (double trisomy included) (38.9%) and triploidy (27.8%) were quite frequently present. The frequency of triploidy among all chromosomal abnormalities was 28.9%, and 53.8% of them were found in partial hydatidiform mole. The rest of them were almost exclusively found in early fetal losses. Complete hydatidiform moles (androgenetic in origin) 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.