Multiple positive points during the 75 g oral glucose tolerance test are good predictors for early insulin therapy in gestational diabetes mellitus diagnosed before 24 gestational weeks

Abstract

ABSTRACT Aims/Introduction This study evaluated the risk factors for insulin therapy before 24 gestational weeks (early insulin therapy) in pregnant women with gestational diabetes diagnosed before 24 gestational weeks (E‐GDM). Materials and Methods This study included 530 singleton mothers with E‐GDM who underwent a 75 g oral glucose tolerance test (OGTT) in the first trimester at Keio University Hospital between January 2013 and December 2021. E‐GDM can be classified according to its management into only diet therapy until delivery (Diet E‐GDM), insulin therapy started before 24 gestational weeks (EarlyIns E‐GDM), and insulin therapy started after 24 gestational weeks (LateIns E‐GDM). We analyzed the risk factors for EarlyIns E‐GDM. Results Patients with EarlyIns E‐GDM had a significantly higher maternal age at delivery, pre‐pregnancy BMI, first trimester hemoglobin A1c, 1 h plasma glucose levels (1 h‐PG), and 2 h‐PG, as well as a more pronounced initial increase and subsequent decrease, compared with those in the Diet E‐GDM group. However, the Apgar scores at both 1 and 5 min were significantly lower in patients with EarlyIns E‐GDM than in those with Diet E‐GDM. The number of abnormal values in the OGTT showed the largest area under the receiver operating characteristic curve (AUC) for predicting EarlyIns E‐GDM (0.83, 95% confidence interval [CI]: 0.79–0.86), followed by the 1 h‐PG value (AUC: 0.81, 95% CI: 0.77–0.85). The initial increase showed the third largest AUC (0.78, 95% CI: 0.74–0.82). Conclusions Although further research is needed, our data suggest the importance of early insulin therapy in cases of E‐GDM with multiple abnormal OGTT values, especially with high 1 h‐PG levels and initial increase.

Keywords

• Gestational diabetes mellitus
• Insulin
• Oral glucose tolerance test