Introduction:
Australian Diabetes in Pregnancy Society (ADIPS) has revised criteria with higher glucose cutoff values for GDM diagnosis. We examined this impact on the GDM prevalence.
Methods:
De-identified post-75g pregnancy oral glucose tolerance test (POGTT) data performed during 2024 were extracted from the laboratory information system of a private and a public pathology in Melbourne, Australia.
GDM was defined according to three guidelines based on glucose (mmol/L): (1) 1999 ADIPS: fasting 5.5-6.9 and/or 2h 8.0-11.0. (2) 2010 International Association of the Diabetes and Pregnancy Study Groups (IADPSG): fasting 5.1-6.9; and/or 1h ³10.0; and/or 2h 8.5-11.0 (endorsed by ADIPS 2014-2025). (3) 2025 ADIPS: fasting 5.3-6.9; and/or 1h ³10.6; and/or 2h 9.0-11.0.
Results:
25,209 and 6,894 POGTTs were performed at the private and public pathology services, respectively. GDM prevalence by each guideline was the same in both services. The overall GDM prevalence was 14.7%, 17.9% and 10.7%, respectively, by the three guidelines described above. The 2025 ADIPS guideline identified 37% -67% lower than other guidelines.
More GDM cases were identified by the 1h or 2h than the fasting glucose cutoffs regardless which guideline was used. Only 36%-38% of the GDM cases were diagnosed by all the three guidelines in both services.
Conclusion:
The 2025 ADIPS guideline will substantially lower the GDM prevalence. Further studies are required to assess its impact on maternal and neonatal outcomes and healthcare costs. Further, a more sophisticated approach to clinical risk is needed to define metabolic risk than just binary (yes/no) GDM status based on glucose levels.