Association between weight/body mass index and insulin dose requirements in gestational diabetes: a retrospective cohort study

Abstract

Abstract Introduction Gestational diabetes mellitus (GDM) is associated with adverse maternal and neonatal outcomes when tight glycemic control is not achieved. Insulin therapy is frequently required to manage fasting hyperglycemia; however, optimal initiation and titration remain challenging within the short treatment window. Weight-based approaches are commonly used to guide insulin prescribing in clinical practice. This study aimed to evaluate whether baseline clinical characteristics, including pre-pregnancy weight and body mass index (BMI), predict insulin requirements in women with GDM. Research design and methods We conducted a retrospective cohort study of women with GDM managed using a rapid insulin titration protocol at our center between 2022 and 2023. Baseline demographic and clinical characteristics, including pre-pregnancy body weight, BMI, and oral glucose tolerance test (OGTT) results, were used to predict the initial insulin dose required to achieve glycemic targets and the maximum insulin dose required during pregnancy. Results Insulin therapy was initiated in 58 women. Marked interindividual variability was observed in both the insulin dose required to achieve glycemic targets and the maximum insulin dose administered. Regression analyses demonstrated poor predictive performance of pre-pregnancy weight and BMI to reliably predict insulin requirements, as reflected by low R² values: initial insulin dose required to achieve glycemic target using weight (R²=0.61) or BMI (R²=0.58) and maximum insulin dose required using weight (R²=0.30) or BMI (R²=0.36). Conclusions Pre-pregnancy weight and baseline BMI have limited utility in predicting insulin requirements in women with GDM. A fixed starting dose with rapid glucose-based titration may represent a more robust way to achieve individualized insulin dose requirements in GDM.