Placental fetal vascularization in neonates with congenital heart disease: a pilot retrospective case control study

Background: Placental function is associated with congenital heart defects (CHD), frequently presenting with malperfusion lesions and small-for-gestational-age size. However, placental villous vasculature in the setting of CHD is understudied. This study evaluated differences in placental, neonatal, and maternal outcomes among maternal/infant dyads with versus without CHD. Methods: We conducted a gestational age- and fetal sex-matched retrospective case control study using specimens prospectively collected by a local biobank. Neonatal outcomes included birthweight, placental weight, and their ratio (placental efficiency). We estimated the proportion of placental villous tissue comprised of fetal vascular endothelial cells (%FVE) using anti-CD34 immunohistochemistry and a pixel count algorithm. Placental weight multiplied by %FVE estimated the grams of placental tissue comprised of villous vasculature (placental vascular index). Maternal outcomes included hypertensive disorders of pregnancy and gestational diabetes. We compared cases and controls using linear and logistic regression adjusted for maternal smoking and cold ischemia time. Stratified analyses examined associations by preterm birth status. Results: Dyads (n=34 with CHD, n=34 without CHD) had maternal age of 29.4 +/- 4.9 years and were 35.6 +/- 4.0 gestational weeks at delivery. Groups had similar placental, neonatal, and maternal parameters. Among preterm neonates, we observed small-to-moderate effect sizes indicating lower placental weight, %FVE, and placental vascular index, and higher placental efficiency, in CHD cases. Among term neonates, moderate effect sizes suggested lower birthweight, placental weight, and placental vascular index in CHD cases. Conclusions: Though differences between groups were not significant, moderate effect sizes suggested that placental vascularization was lower among preterm neonates with CHD.