Endocrine Abstracts

Background: Women with gestational diabetes (GDM) have a ≥6-fold increased risk of developing type 2 diabetes, with highest risks observed in women with postpartum dysglycaemia (PPD) on an oral glucose tolerance test (OGTT) performed 6-12 weeks postpartum. This study aims to identify predictors of PPD in women with a history of GDM.

Methods: From 01/10/2023-31/07/2025, we prospectively assessed women prior GDM who completed a 75-g OGTT 6-12 weeks postpartum. The primary outcome was PPD (2-hr glucose ≥5.6mmol/l). Univariate and multivariate logistic regression were performed, with multiple imputation for missing data and multicollinearity checks. Model performance was evaluated using AUC and Brier score with 1,000 bootstrap iterations for internal validation. Predictor importance was evaluated via dominance analysis. Optimal thresholds for continuous variables were identified using Youden’s index.

Results: 40/409 women (34.2%) developed PPD. Predictors included higher maternal age (OR 1.05, 95% CI 1.00-1.10, P = 0.048), higher antepartum 2-hr OGTT glucose (OR 2.03, 95% CI 1.31-3.20, P < 0.001), higher HbA1c at GDM diagnosis (OR 3.08, 95% CI 1.95-4.99, P = 0.002), and family history of diabetes (OR 2.29, 95% CI 1.55-3.42, P < 0.001). Compared to Malay women, Chinese women had increased odds of PPD (OR 1.77, 95% CI 1.07-2.95, P = 0.026). In-vitro fertilisation (OR 0.19, 95% CI 0.07–0.47, P < 0.0001) and pre-pregnancy BMI (OR 0.95, 95% CI 0.92–0.99, P = 0.011) were associated with decreased risk of PPD. Model performance was acceptable (AUC 0.77, 95% CI 0.72–0.81; Brier 0.17, 95% CI 0.16-0.19). Dominance analysis identified 2-hr OGTT as the strongest contributor to model variance (32.5%) followed by family history (16.3%), ethnicity (15.4%) and HbA1c (13.0%). The Youden-optimised HbA1c threshold for predicting postpartum dysglycaemia was 5.5% (36mmol/mol).

Conclusions: Antepartum parameters may identify women at highest risk of PPD and could inform targeted intervention within postpartum diabetes care pathways.