High rate of placental infarcts in type 2 compared with type 1 diabetes

Timing and cause of pregnancy loss differ between type 1 (T1DM) and type 2 diabetes mellitus (T2DM).

The objective of the study was to determine whether placental histology corresponds to differing causes of pregnancy loss in T1DM and T2DM. We hypothesized that placentas from mothers with T2DM would be more likely to demonstrate vascular pathology than those from mothers with T1DM. RESEARCH DESIGN/SETTING/PARTICIPANTS: We reviewed medical histories, pregnancy outcomes, and placental histology of women with pregestational T1DM and T2DM with singleton pregnancies between 2001 and 2009 at a single tertiary care medical center.

Placental weight, placental dysmaturity, villous maturation, villitis of unclear etiology, and histological evidence of placental infarction were measured.

Ninety-eight placentas were available for review, 53 from T1DM mothers (56%) and 45 from T2DM mothers (46%). Mean age and glycemic control each trimester did not differ between diabetes types. T2DM placentas had a higher prevalence of placental infarcts (22 vs. 6%, P = 0.02) and a lower prevalence of placental dysmaturity (12 vs. 29%, P = 0.05) compared with T1DM; rates differed from those reported in the general population. There was no difference in placental weight, villous maturity, or villitis of unclear etiology between diabetes types.

There were many similarities in placental histological findings between diabetes types. Still, one in five T2DM placentas displayed histological infarcts, consistent with a vascular, rather than glycemic, etiology of pregnancy complications, whereas T1DM placentas showed signs of abnormal development.