Oral Presentation Australasian Diabetes in Pregnancy Society Annual Scientific Meeting 2024

Postpartum Glucose Tolerance after Early Gestational Diabetes: Follow-up of Women in the TOBOGM Study (#14)

N Wah Cheung 1 2 , Yoon JJ Rhou 1 2 , Jincy Immanuel 3 4 , Bill M Hague 5 , Helena Teede 6 , Christopher J Nolan 7 , Michael J Peek 2 8 , Jeff R Flack 9 , Mark Mclean 10 , Vincent Wong 11 12 , Emily J Hibbert 2 8 , Alexandra Kautzy-Willer 13 , Jürgen Harreiter 13 14 , Helena Backman 15 , Emily Gianatti 16 , Arianne Sweeting 17 , Viswanathan Mohan 18 , David Simmons 4
  1. Department of Diabetes & Endocrinology, Westmead Hospital, Westmead, NSW, Australia
  2. University of Sydney, Sydney
  3. Texas Woman's Hospital, Denton, TX, USA
  4. Western Sydney University, Campbelltown, NSW, Australia
  5. Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia
  6. Monash University, Melbourne, Victoria, Australia
  7. Canberra Hospital and Australian National University, Canberra, ACT, Australia
  8. Nepean Hospital, Penrith, NSW, Australia
  9. Bankstown-Lidcombe Hospital, Sydney, NSW, Australia
  10. Dept of Diabetes & Endocrinology, Blacktown Hospital, Sydney
  11. Liverpool Hospital, Liverpool, NSW, Australia
  12. University of NSW, Randwick, NSW, Australia
  13. Gender Medicine Unit, Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
  14. Department of Medicine, Landesklinikum Scheibbs, Austria
  15. Dept of Obstetrics and Gynecology, Faculty of Medicine and Health, Orebro University, Orebro, Sweden
  16. Dept of Endocrinology, Fiona Stanley Hospital, Murdoch, WA, Australia
  17. Dept of Endocrinology, Royal Prince Alfred Hospital, Sydney, NSW, Australia
  18. Dr Mohan’s Diabetes Specialities Centre and Madras Diabetes Research Foundation, Chennai, India

Background: Previous studies conducted among women diagnosed with gestational diabetes (GDM) on the basis of IADPSG criteria at the standard time of 24-28 weeks have found that 1-5% will have diabetes on testing shortly after pregnancy, and 15-40% will have any form of dysglycaemia. There are little data as to whether women with early GDM are more likely or not to have postpartum dysglycaemia. The aim of this substudy of the Treatment of Booking Gestational Diabetes (TOBOGM) randomised controlled trial (RCT)1, is to evaluate the incidence and predictors of postpartum dysglycaemia among women who develop early GDM.

Research and Design Methods: The TOBOGM Study was a RCT of early or delayed treatment for women diagnosed with early GDM. Participants were diagnosed with GDM prior to 20 weeks gestation, on the basis of the IADPSG criteria for GDM. Those with a fasting glucose ≥6.1 mmol/L and/or 2-hour glucose ≥11.1 mmol/L were excluded. Participants in the study were recommended to have an oral glucose tolerance test (oGTT) 6-12 weeks postpartum. oGTT results were categorised as normal, diabetes, impaired fasting glucose (IFG, fasting glucose 6.1-6.9 mmol/L), and impaired glucose tolerance (IGT, 2 hour glucose 7.8-11.0 mmol/L). Multivariate analysis was conducted by backwards stepwise logistic regression to determine independent predictors of abnormal postpartum glucose tolerance.

Results: Three hundred and fifty two of 793 participants in the TOBOGM Study underwent a postpartum oGTT. There were 63 (18%) participants with postpartum dysglycaemia: 11 (3.1%) with diabetes, 2 (0.6%) with IFG, 48 (13.6%) with IGT, and 2 (0.6%) with combined IFG and IGT. Women who had abnormal postpartum glucose tolerance were more likely to have had previous GDM, be a smoker, have lower BMI, greater gestational weight gain, and have higher glucose values on the early pregnancy oGTT. On multivariate analysis, which included baseline and pregnancy variables, higher 2-hour glucose level at the early pregnancy oGTT (OR 1.59, 95%CI 1.26-2.00, p<0.01), previous GDM (OR 2.30, 95%CI 1.10-4.77, p=0.03) and gestational weight gain (OR 1.07, 95%CI 1.01-1.13, p=0.02) were the factors which were independently associated with abnormal postpartum glucose tolerance.

Conclusion: The incidence of postpartum dysglycaemia among women with early GDM (excluding those with overt diabetes) in the TOBOGM Study is similar to that observed in follow up studies where women were primarily diagnosed with GDM at 24-28 weeks gestation.

  1. Simmons D, Immanuel J, Hague WM, Teede H, Nolan CJ, Peek MJ, Flack JR, McLean M, Wong V, Hibbert E, Kautzky-Willer A, Harreiter J, Backman H, Gianatti E, Sweeting A, Mohan V, Enticott J, Cheung NW. Treatment of gestational diabetes diagnosed early in pregnancy. N Eng J Med 2023; 388: 2132-44.