ADIPS Poster Presentation Australasian Diabetes in Pregnancy Society and Society of Obstetric Medicine Australia and New Zealand Joint Scientific Meeting 2025

The impact of increasing the diagnostic thresholds for gestational diabetes mellitus in the Northern Territory (#203)

Matthew Hare 1 2 , Molly Robbins 3 4 , Kiarna Brown 1 5 , Renae Kirkham 3 , Winnie Chen 1 6 7 , Isabell Marovich-Tadic 1 , Elizabeth Moore 8 , Louise Maple-Brown 1 2
  1. Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
  2. Endocrinology Department, Royal Darwin Hospital, Darwin, NT, Australia
  3. Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia, Darwin
  4. Flinders University, Darwin, NT, Australia, Darwin
  5. Department of Obstetrics and Gynaecology, Royal Darwin Hospital, Darwin, NT, Australia, Darwin
  6. Danila Dilba Health Service, Darwin, NT, Australia, Darwin
  7. Leader Centre for Health Policy, Economics and Data, University of Sydney, Sydney, NSW, Australia, NSW
  8. Public Health Unit, Aboriginal Medical Services Alliance Northern Territory, Darwin, NT, Australia, Darwin

Objective: The Australasian Diabetes in Pregnancy Society (ADIPS) has recently published new recommendations that increase the diagnostic thresholds for gestational diabetes mellitus (GDM). This study aims to identify the clinical and health service implications of increasing the thresholds for pregnant women in the Northern Territory (NT).

 

Methods: A retrospective analysis of data from the NT Diabetes in Pregnancy Clinical Register was conducted, comparing maternal and neonatal outcomes for pregnancies that would no longer be diagnosed with GDM with pregnancies still diagnosed under the new diagnostic criteria for GDM and overt diabetes in pregnancy (DIP). Singleton pregnancies between January 2015 and December 2019 were included. Women with pre-existing diabetes were excluded.

 

Results: Of the 1089 pregnancies included, 713 (65%) diagnoses of GDM or overt DIP were maintained under the new criteria, while 376 (35%) were not. Ethnicity varied across the two groups (p=0.005). There was a 41% reduction in diagnoses among Europid women and a 28% reduction among Aboriginal and/or Torres Strait Islander women. Rates of metformin use, macrosomia, induction of labour, caesarean section, neonatal hypoglycaemia and special care admission were similar among

pregnancies meeting the new criteria and those which did not. Insulin use was higher in pregnancies meeting the new criteria (16% vs 10%, p=0.016).

 

Conclusion: Using the ADIPS 2025 recommendations, 35% fewer GDM diagnoses would have been made. In this treated retrospective cohort, risk of adverse pregnancy outcomes was similar among those with a maintained GDM diagnosis and those who would no longer be diagnosed with GDM