Prepregnancy hemoglobin levels and gestational diabetes mellitus in pregnancy

Aim: To identify the influence of prepregnancy hemoglobin levels on gestational diabetes mellitus. Materials and Methods: Korean women who had given birth between January 1st, 2006 and December 31st, 2015 and who had undergone a biannual national health screening examination within 6 months prior to pregnancy were enrolled. Subjects were divided into three groups according to their hemoglobin levels. Multivariate logistic regression analysis was used to estimate the adjusted odds ratio and 95% confidence interval for GDM. Results: Of the 366,122 participants, GDM developed in 14,799 (4%) women. More specifically, GDM developed in 3.6% of women with prepregnancy anemia (hemoglobin < 11 g/dL), 3.57% with normal hemoglobin levels, and 4.47% with hemoglobin levels higher than 13 g/dL. We did not find any association between prepregnancy anemia and the risk of developing GDM (OR 1.002 [95% CI 0.90–1.11]). After adjusting for potential confounding factors (adjusted odds ratio 1.41; 95% CI 1.29–1.54), high hemoglobin levels were associated with insulin requiring GDM. Conclusions: Our study identified an association between high prepregnancy hemoglobin levels and GDM risk.