Patients with gestational diabetes mellitus may be treated in both early and late pregnancy, especially in patients with pre-pregnancy overweight: A cross-sectional study in Japan.

The significance of diagnosing gestational diabetes mellitus (GDM) in early pregnancy is controversial. We used the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria to investigate whether clinical background and neonatal outcomes differ depending on when GDM is diagnosed in early or late pregnancy. This was a single-center, observational study conducted between November 2012 and March 2020 at St. Marianna University Hospital (Kawasaki, Japan). We compared the background and perinatal outcomes of patients with GDM depending on the time of diagnosis (at < 24 gestational weeks or ≥ 24 weeks). Insulin sensitivity index, homeostasis model assessment of insulin resistance, and β-cell function were calculated from a 75-g oral glucose tolerance test. Stratified analysis was performed by pre-pregnancy BMI in patients with early GDM. As a result, in the 507 patients, 89.9% gave birth at our hospital. The pre-pregnancy BMI was significantly higher in patients with early GDM than in those with late GDM (the median [interquartile range], 22.7 [20.3, 26.3] and 21.5 [19.3, 23.8] kg/m², respectively; p = 0.001). Perinatal outcomes were not different between the two groups. However, in the subgroup analysis of patients with early GDM, the prevalence of large-for-gestational-age infants was significantly higher in the group with overweight (15.4% vs 2.1%, respectively; p = 0.008). In conclusion, patients with GDM using the IADPSG criteria in early pregnancy may be treated, especially in patients with pre-pregnancy overweight.