Clinicopathological correlation of large-for-gestational age placenta in pregnancies with pregestational diabetes

Studies have demonstrated an association between pregestational diabetes (preGDM) and a higher prevalence of large-for-gestational age placentas (LGA). However, frequency of placental pathologies and perinatal outcomes in LGA placentas is lacking. We aimed to determine differences in perinatal outcome or placental pathology between LGA placentas and appropriate-for-gestational age (AGA) placentas from pregnancies complicated by preGDM. We found LGA placentas are associated with significantly higher neonatal weight but lower fetal-to-placental weight ratio (f/p) for both T1DM and T2DM. T2DM LGA placentas possessed a significantly higher prevalence of placental insufficiency (f/p<10^th percentile). Compared to LGA groups, more chronic villitis were seen in the AGA T2DM group, and more acute chorioamnionitis in the T1DM AGA group. No significant differences were seen in maternal BMI or glycemic control. In pregnancies complicated with preGDM, LGA placentas had generally lower placental efficiency than AGA placentas.