Postpartum dysglycaemia after early gestational diabetes: follow-up of women in the TOBOGM randomised controlled trial

Aim: To evaluate the incidence and predictors of postpartum dysglycaemia among high-risk women who develop early gestational diabetes (eGDM) prior to 20 weeks' gestation. Methods: This is a sub-study of the Treatment of Booking Gestational Diabetes (TOBOGM) Study, a randomised controlled trial of early or deferred treatment for women with risk factors for gestational diabetes diagnosed with eGDM, using current WHO criteria. Overt diabetes in pregnancy was excluded. A repeat oral glucose tolerance test (oGTT) was recommended at 6-12 weeks postpartum. Results: Of 793 participants, 352 (44.4%) underwent a postpartum oGTT. Baseline characteristics of participants with and without an oGTT were similar. Ninety-two (26.1%) had postpartum dysglycaemia: 11 (3.1%) diabetes, 31 (8.8%) impaired fasting glucose (IFG), 39 (11.1%) impaired glucose tolerance (IGT), and 11 (3.1%) combined IFG/IGT. Participants with postpartum dysglycaemia were more likely to have had past GDM, lower body mass index, more gestational weight gain, and higher 1 and 2-hour glucose concentrations on the early pregnancy oGTT. On logistic regression, higher 1 and 2-hour glucose concentration, previous GDM and greater gestational weight gain were independently associated with postpartum dysglycaemia. Conclusion: There is a high incidence of postpartum dysglycaemia among high-risk women with eGDM.