Abstract
INTRODUCTION: Gestational diabetes mellitus (GDM) is associated with metabolic risks and adverse maternal and fetal perinatal outcomes. This study aimed to compare pregnancy outcomes, postpartum glucose intolerance and insulin secretion capacity in women with early-onset GDM (EGDM, diagnosed<24 weeks) and late GDM (LGDM, diagnosed≥24 weeks) in Japan. RESEARCH DESIGN AND METHODS: This single-center, retrospective study included 107 women with EGDM and 109 with LGDM. GDM was diagnosed through the 75 g oral glucose tolerance test. Postpartum glucose tolerance was assessed 4-16 weeks post partum. Maternal and neonatal outcomes, insulin secretion, and postpartum glucose tolerance were analyzed and compared. Subgroup analyses were performed for women with and without obesity. RESULTS: Although gestational weight gain was significantly lower in women with EGDM than in those with LGDM, pregnancy outcomes, including neonatal birth weight, small for gestational age and large for gestational age, were comparable between the two groups. However, postpartum glucose intolerance was more prevalent in women with EGDM, particularly in those without obesity who also had significantly lower initial insulin secretion capacity. Insulin resistance was comparable between the groups, suggesting that reduced insulin secretion, rather than insulin resistance, contributes to postpartum glucose intolerance in EGDM. CONCLUSIONS: EGDM in women without obesity is associated with a high risk for postpartum glucose intolerance. This could be related to impaired insulin secretion rather than insulin resistance. These findings highlight the need for close monitoring and tailored interventions for patients with EGDM. More research is required to improve diagnostic and management strategies, considering ethnic variations in insulin secretion and glucose tolerance.