OBJECTIVE: The objective of this study is to test if chorionic villus sampling (CVS) is associated with fetal growth impairment, after controlling for maternal and fetal factors.STUDY DESIGN: Case-control study of singleton fetuses whose mothers had undergone CVS (N = 442) and 2969 controls. The primary outcomes were the prevalence of birthweight < 10th centile and birthweight <3rd centile; the prevalence of preeclampsia was the secondary outcome. Tested predictors in logistic regression analysis included CVS, free beta-hCG MoMs, PAPP-A MoMs, first-trimester mean uterine artery pulsatility index (PI) z-scores, maternal height, BMI, age, and smoking.RESULTS: The proportion of newborns with birthweight <10th centile (7.9 versus 6.2%), and <3rd centile (1.6 versus 1.1%) did not differ between the two groups. Maternal age, smoking during pregnancy, PAPP-A MoMs, and mean first-trimester uterine PI z-score were significant predictors for these outcomes. Although the prevalence of preeclampsia was higher in the CVS group (3.2 versus 1.3%, OR 2.62, 95% CI 1.41-4.89), the association was abolished in the regression analysis, in which maternal body mass index, free b-hCG levels, and mean first-trimester uterine PI z-score were the only significant predictors.CONCLUSIONS: CVS is not associated with fetal growth impairment, possibly because the resulting mechanical disruption is compensated by the developing placenta, without significantly impairing its function.