Decidual arteriolopathy with or without associated hypertension modifies the underlying histomorphology in placentas from diabetic mothers

Aim The aim of this study was to retrospectively document the impact of hypertensive conditions in pregnancy and decidual arteriolopathy on the patterns of placental injury in maternal diabetes mellitus (MDM). Methods Among all 5248 > 20 weeks’ placentas, the frequencies of 19 selected clinical and 24 placental phenotypes were compared between 287 MDM placentas and 4961 remaining placentas (control group [CG]) before and after further exclusion of 85 and 611 patients with hypertensive conditions (gestational hypertension, pre‐eclampsia, chronic hypertension). Results Cesarean section rate, heavy placentas, decidual arteriolopathy, microscopic chorionic pseudocysts, and chorangiosis were more common in MDM than in the CG both before and after exclusion of hypertensive conditions. The frequencies of preuterine patterns of chronic hypoxic placental injury and plasma cell deciduitis became statistically significant only after exclusion of hypertensive conditions. Conclusion Hypertensive conditions of pregnancy may obscure the underlying preuterine placental hypoxic pattern in MDM placentas. Even in normotensive patients, decidual arteriolopathy, and shallow placental implantation significantly impact placental histomorphology in MDM.