Transcervical chorionic villus sampling and amniocentesis: a comparison of reliability, culture findings, and fetal outcome.

We evaluated the reliability, culture findings, and fetal outcome after transcervical chorionic villus sampling or amniocentesis in a group of 860 patients. All procedures were performed for the indication of advanced maternal age with consistent procedure and laboratory techniques. Successful procedures were completed in 97.7% (420/430) of patients in the chorionic villus sampling group, compared with 99.5% (428/430) in the amniocentesis group (p less than 0.01). Success was more frequent with only one attempt in the amniocentesis group (427/428) versus 354 of 420 in the chorionic villus sampling group (p less than 0.001). Culture failure was more common after chorionic villus sampling (p less than 0.001). Pregnancy loss rates through 28 weeks' gestation and the entire gestation were not significantly different. The prevalence of preterm delivery did not vary between groups, but birth weights of infants in the chorionic villus sampling group were significantly greater. In summary, the present investigation supports previous findings that chorionic villus sampling is a safe alternative to amniocentesis and is not associated with long-term pregnancy complications.