Improved method for study of chromosomes of chorionic villus samples.

Chorionic villus sampling (CVS) offers rapid prenatal diagnosis of chromosomal disorders. We evaluated four methods for chromosomal analysis of chorionic villi (three based on direct preparations and one on long-term culture) in order to define a method which would provide good quality metaphases in sufficient numbers. The direct culturing method using synchronisation and dissociation with dispase was as good as long-term culturing. The optimal period of gestation for study was 10-12 wk.