Fasting glucose levels at diagnosis and delivery are associated with postpartum glucose abnormalities in GDM women

Women with a history of gestational diabetes mellitus (GDM) significantly increase the risk of developing type 2 diabetes later in life. Although the increased glucose levels typically return to normal range after delivery for most GDM women, a significant proportion of GDM women develop impaired glucose tolerance or overt diabetes after delivery. Several factors associated with postpartum glucose abnormalities have been identified, yet the link between fasting glucose levels at diagnosis of GDM and postpartum glucose abnormalities remains unclear. In this retrospective study with 866 GDM women, we found that 12.5% presented with abnormal postpartum fasting glucose levels (prediabetes). Among those with postpartum fasting glucose abnormalities (n = 109), 63 (57%) women had abnormal fasting glucose levels at diagnosis, indicating an odds ratio of 1.662 (95% CI: 1.12, 2.479, p < 0.001) for these GDM women developing postpartum fasting glucose abnormalities, compared to those GDM women with normal postpartum fasting glucose levels. Additionally, of GDM women with abnormal postpartum glucose levels (n = 109),70 (64%) presented with abnormal fasting glucose levels one day before delivery. The odds ratio for these GDM women presenting with abnormal postpartum fasting glucose levels was 3.751 (95% CI: 2.462, 5.664, p < 0.001) compared to those GDM women with normal postpartum fasting glucose levels. Furthermore, GDM women with additional insulin treatment or delivered an LGA infant significantly increased the risk of developing postpartum fasting glucose abnormalities. Our findings suggest that abnormal fasting glucose levels at diagnosis or shortly before delivery could be a predictive indicator for postpartum glucose abnormalities in GDM women.