Chorionic villi sampling: a new technique for detection of genetic abnormalities in the first trimester.

Chorionic villi sampling (CVS) was performed on 22 patients who were at risk for a variety of genetic disorders between 8.5-11 weeks of gestation to determine whether the developing fetus had a chromosomal and/or biochemical disorder. A thin Portex catheter was passed transcervically into the chorion frondosum under constant real-time ultrasound guidance, and chorionic villi were obtained by gentle suction. The villi, which have the same genotype as the fetus, were processed directly for chromosomal and/or biochemical analysis. Results were available within six to 24 hours and were confirmed by short term cell cultures within three to ten days. One fetus affected with Tay-Sachs disease and one fetus with trisomy 16 were detected. There were no instances of fetal loss or major complications. In contrast to amniocentesis, the procedure is performed early in pregnancy and results of the genetic testing are available during the first trimester, which allows a first trimester termination of pregnancy if an abnormality is detected and greatly reduces parental anxiety if the findings are normal. We believe that CVS offers an alternative to amniocentesis in the detection of genetic disorders.