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.

Keywords: Indigenous population; antenatal care; hyperglycemia in pregnancy; population health; postpartum hemorrhage.