Analysis of fetal loss after transcervical chorionic villus sampling--a review of 719 patients.

Chorionic villus sampling was performed under real-time ultrasonographic direction on a study group of 719 patients from September 9, 1985, through May 5, 1988. Follow-up of 714 of these patients who would have reached 28 weeks' gestation on September 1, 1988, revealed "an unintended" abortion rate of 4.1% by 20 weeks' gestation. Nine patients had a fetal loss less than 4 weeks after the procedure; 19 had losses up to 12 weeks after the procedure and before 20 weeks' gestation. This study revealed a significantly increased risk of fetal loss with an increase in the number of catheter insertions (p less than 0.001). The risk of fetal loss after one sampling attempt was 3%, 7.8% after two attempts, and 14.3% after three attempts.