Comparison of placental findings in type 1 and type 2 diabetic pregnancies

•An updated knowledge of pregestational diabetic placental pathology.•Comparison of placental pathology and clinical parameters between type 1 and 2 diabetic pregnancies.•Findings of significant small for gestational age placentas in diabetic pregnancy.•More pathology related to maternal underperfusion and insufficiency in type 2.•More discrepancy between pathology and glycemic control in type 2.

IntroductionThe aim of this study is to compare placental pathology and related clinical parameters between gravidas with type 1 and type 2 pregestational diabetes.MethodsThis is a retrospective cohort study of women with singleton gestations and pregestational diabetes who delivered at Women and Infants Hospital from 2003 to 2011. Pathology reports, maternal and neonatal outcomes were extracted and compared between the two groups.ResultsIn our cohort, 293 pregnancies were studied, including 117 with type 1 diabetes and 176 with type 2 diabetes. Women with type 1 diabetes had worse glycemic control during pregnancy, as characterized by higher HbA1c values and average fasting and postprandial blood sugars. More infants from the type 1 group were admitted to Neonatal ICU. Pregestational diabetes led to small for gestational age (SGA) placentas in nearly 20% pregnancies and large for gestational age (LGA) placentas in 30% of cases. Both groups shared similar incidences of preeclampsia and significant placental pathology related to uteroplacental (maternal) and fetal circulatory disorders; however, maternal decidual vasculopathy and placentas with insufficiency (fetal-to-placental weight ratio < 10th %tile) were more commonly found in placentas from women with type 2 diabetes.DiscussionBoth types of pregestational diabetes have significant impact on placental growth and development. The comparison between the two groups suggests different pathogenetic mechanisms and may be helpful for better management of diabetic pregnancy.