Gestational diabetes is associated with postpartum hemorrhage in Indigenous Australian women in the PANDORA study: A prospective cohort

Abstract Objective To assess associations of hyperglycemia in pregnancy with the risk of postpartum hemorrhage (PPH) in a prospective cohort of Indigenous and non‐Indigenous women, compared with normoglycemia. Methods Data were from 1102 (48% Indigenous) women of the Pregnancy And Neonatal Diabetes Outcomes in Remote Australia (PANDORA) Study. Age‐adjusted associations of gestational diabetes mellitus (GDM) or pre‐existing type 2 diabetes mellitus (T2DM), obstetric and demographic covariables with PPH (blood loss ≥500 ml) were assessed using logistic regression. Multivariable‐adjusted models included Indigenous ethnicity, diabetes type and their interaction. Results A higher proportion of Indigenous women developed PPH than non‐Indigenous women (32% versus 22%; P < 0.001). Compared with non‐Indigenous women with normoglycemia, risks of PPH for Indigenous women with GDM or T2DM were higher (odds ratio [OR] 1.83, 95% confidence intervals [CI] 1.11–3.02, and OR 1.72, 95% CI 0.99–3.00 after age adjustment, OR 1.84, 95% CI 1.06–3.19, and OR 1.33, 95% CI 0.70–2.54 after adjustment for school education and delivery mode, and OR 1.62, 95% CI 0.95–2.77, and OR 0.99, 95% CI 0.53–1.86 after adjustment for birth weight). Importantly, Indigenous women without hyperglycemia in pregnancy were not at increased risk of PPH. Conclusion The significantly higher rates of PPH experienced by Indigenous women compared with non‐Indigenous women may be explained by a greater effect of GDM among Indigenous women that was only partly accounted for by birth weight.