Cook obstetrics and gynecology catheter multicenter chorionic villus sampling trial: comparison of birth defects with expected rates.

Abstract

The null hypothesis was that offspring of women undergoing first-trimester chorionic villus sampling do not experience a rate of birth defects exceeding background rates. Follow-up information regarding major malformations was prospectively sought on offspring of 4105 women undergoing first-trimester chorionic villus sampling from nine centers participating in a collaborative study with the Cook obstetrics and gynecology catheter. These data were compared with data from the Collaborative Perinatal Project and other registries. A total of 84 offspring with major malformations was identified (2.36%). Compared with background rates, there was no increase in the incidence of total malformations or specific malformations (including limb reduction defects) in the subjects. One institution experienced all three limb reduction defects in this series; the probability of this occurring by chance alone is < 1%. Chorionic villus sampling was not found to result in an increase in major birth defects or in specific categories of birth defects in this series.