A cytogenetic study of spontaneous abortions with direct analysis of chorionic villi.

The karyotypes of 144 spontaneous abortuses were determined using direct chromosome preparations from chorionic villi. The frequency of chromosome abnormality was 69.4%, which is considerably higher than figures cited in most previous cytogenetic surveys using the conventional method of cell culturing. Autosomal trisomy was the predominant abnormality (64%), followed by polyploidy (9%), monosomy X (7%), structural rearrangements (6%), mosaicism (6%), double trisomy (4%), and double chromosome anomaly (3%). Direct preparations have advantages in that results can be obtained rapidly, the success rate of karyotyping is satisfactory, and maternal-cell contamination is minimal.