910: Abnormal chorionic villi morphology and risk of aneuploidy

Abstract

To evaluate the association between chorionic villi morphology and aneuploidy on chorionic villus sampling (CVS), using a simple morphologic scoring system. This was a retrospective cohort study of singleton pregnancies that underwent CVS at a single institution from 2006 to 2017. A simple scoring method was utilized to evaluate each specimen with regards to number of buds, branches, and veins. These budding, branching, and vascularity scores ranged from 0 to 3, with 0 indicating the absence of the structure, 1 indicating presence in < 25% of the sample, 2 indicating presence in 25- 75% of the sample, and 3 indicating presence in > 75% of the sample. A composite score was calculated as a sum of the individual scores. Based on the distribution of scores in this cohort, individual scores were re-categorized into normal (1-2) and abnormal (0 or 3), and the composite score was re-categorized into normal (3-6) and abnormal (0- 2 or 7-9). The primary predictors were abnormal budding, branching, vascularity, and composites scores, while the primary outcome was presence of aneuploidy on cytogenetics. Fisher’s exact test compared proportions between categorical groups, and logistic regression generated odds ratios. A total of 1,175 CVS specimens met criteria for inclusion, with 30.6% demonstrating aneuploidy. There was no statistically significant difference in rate of abnormal budding score between the two groups (2.2% aneuploid vs 2.5% euploid, p = 0.81). The difference in rate of abnormal branching score approached but did not reach statistical significance (5.0% aneuploid vs 2.8%, euploid p = 0.06). There was a statistically significant difference in rate of abnormal vascularity score (5.0% aneuploid vs 1.8% euploid, p = 0.002, OR 2.8, 95% CI 1.4-5.6) and in rate of abnormal composite score (7.2% aneuploid vs 3.8% euploid, p = 0.012, OR 2.0, 95% CI 1.2-3.4) between the two groups. We found that an abnormal composite morphologic score was associated with aneuploidy on CVS specimens. While other studies have demonstrated an association between aneuploidy and complex aspects of chorionic villus histomorphology, this scoring system is simple, rapid, and easy for clinical cytogeneticists to perform at the time of routine diagnosis. Future studies should evaluate the potential association between abnormal morphologic scores and placentally-mediated adverse pregnancy outcomes, such as hypertensive disorders and fetal growth restriction.View Large Image Figure ViewerDownload Hi-res image Download (PPT)