Placental pathology findings and birth weight discordance

Purpose: To assess the fetal, perinatal, and maternal outcomes in twin pregnancy according to chorionicity. Materials and Methods: This was a retrospective cohort study of 1,571 twin pregnancies with placental pathological examination collected from 2000-2010. Fetal, neonatal, and maternal outcomes of twins were compared via multivariate analysis. Results: Placenta anastomosis, unequal placenta sharing, cord size, and cord insertion type were found to be the key elements that impacted growth discordance in twin gestations. Higher rates of severe growth discordance were negatively associated with higher frequencies of anastomosis. Placentas in monochorionic twins were more likely to have shared arteries/veins. Discussion: Monochorionic placentas compensate for lack of nutritional flow by penetrating to other placenta surfaces. Compensation for lack of vascular sufficiency would mean a fused placenta or sharing more portions of the placenta. Higher rates of unequal placenta sharing among growth discordant twins is reported irrespective of chorionicity. Conclusion: Attention to placenta pathology is important in growth discordant twins.