Gross morphologic appearance of chorionic villi and the risk of chromosomal abnormalities

Chromosomal abnormalities are associated with changes in complex aspects of chorionic villi histomorphology. This study used a simple scoring system to evaluate the association between atypical gross morphology and abnormal chromosomal testing on chorionic villus sampling (CVS). This retrospective cohort study included singleton pregnancies that underwent CVS at a single institution from 2006-2017. The degree of budding, branching, and vascularity (BBV) was scored from 0 to 3 for each CVS specimen, and individual scores were summed to calculate a composite BBV score. Scores were categorized into typical or atypical based on the cohort’s distribution. The primary predictor was atypical BBV score, and the primary outcome was chromosomal abnormality. Fisher’s exact test compared proportions, and logistic regression generated odds ratios. Among 1171 CVS specimens, 28% had chromosomal abnormalities. The chromosomally abnormal group had a higher rate of atypical BBV score than the normal group (7.3% vs 3.7%, P=0.009), a finding that remained statistically significant after controlling for maternal age, gestational age, and mode of CVS (aOR 2.2, 95% CI 1.24-3.82). Atypical chorionic villus morphology is associated with chromosomal abnormalities. This scoring system is simple, rapid, and easy to perform at the time of routine diagnosis.