Oral Presentation Australasian Diabetes in Pregnancy Society Conference 2026

Intergenerational associations between diabetes in pregnancy and birthweight across three generations among Aboriginal and Torres Strait Islander people in the Northern Territory (140623)

Matthew J. L. Hare 1 2 , Tahmina Begum 3 , Isabella Marovich-Tadic 1 , Norlisha Bartlett 1 , Elizabeth L. M. Barr 1 , Jonathan E. Shaw 4 , Jacqueline A. Boyle 5 , Roland F. Dyck 6 7 , Louise J. Maple-Brown 1 2 , Federica Barzi 3
  1. Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
  2. Endocrinology Department, Royal Darwin Hospital, Darwin, NT, Australia
  3. Poche Centre for Indigenous Health, The University of Queensland, Brisbane, QLD, Australia
  4. Clinical Diabetes and Epidemiology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
  5. Eastern Health Clinical School, Monash University, Melbourne, VIC, Australia
  6. Department of Medicine (Canadian Centre for Rural and Agricultural Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
  7. Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Background: The prevalence of type 2 diabetes in Aboriginal and Torres Strait Islander people of the Northern Territory (NT) is among the highest reported globally. In-utero exposure to maternal diabetes in pregnancy is hypothesised to be a key driver of the ongoing diabetes epidemic. No Australian study has demonstrated associations between maternal diabetes in pregnancy (DIP) and diabetes outcomes in subsequent generations.

Aim: To investigate associations between grandmaternal (generation G0) DIP, maternal (G1) DIP and grandchild (G2) birthweight, among Aboriginal and Torres Strait Islander women.

Methods: This population-based longitudinal study used data from the NT Perinatal Data Collection (1986-2016). To be included, G1 women had to be born in the NT since 1986 and have their own birth and that of their child(ren) recorded in the dataset. Record linkage was performed using the longstanding NT-wide Hospital Reference Number (HRN). Data from non-Indigenous people or non-singleton pregnancies were excluded. Multivariable regression models using generalised estimating equations were used to explore associations and potential confounders between generations. Mediation analysis was performed using the “mediate” command in Stata v.18. The primary exposure was G0 DIP status and the primary outcome was large-for-gestational age in G2.

Results: 5,487 triads of birth data were included. A diagnosis of diabetes (including any type of hyperglycaemia in pregnancy) was documented in 5.6% (n=309) of pregnancies among grandmothers (G0, born from 1945-1987) and in 8.9% (n=486) of pregnancies among mothers (G1, born from 1986-2004). Male and female G2 children were born from 2000-2016. Compared to those unexposed to maternal DIP, G1 women exposed in-utero to DIP (G0) were more likely to develop DIP (adjusted OR 2.57, 95% CI: 1.87-3.51). Grandmaternal (G0) DIP was associated with large-for-gestational age in G2 (aOR 1.86, 95% CI: 1.18-2.91), with mediation analyses suggesting that maternal (G1) DIP accounted for 57% of the association between grandmaternal DIP and large-for-gestational-age in G2.

Conclusion: This study demonstrates associations between diabetes in pregnancy and birthweight outcomes across three generations, suggesting both intergenerational and transgenerational impacts of diabetes in pregnancy among Aboriginal and Torres Strait Islander people. Strategies to enhance pre-conception and pregnancy health may benefit multiple generations.