Oral Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2026

In-Utero Metformin Exposure and Offspring Development at 4–6 Years: A Population-Based Cohort Study From Victoria, Australia (141569)

Hannah Gordon 1 2 , Richard Hiscock 1 2 , Sarah Price 1 3 , Alexis Shub 1 2 , Alexandra Roddy Mitchell 1 2 , Jessica Atkinson 1 2 , Sue Walker 1 2 , Anna Forsythe 1 2 , Stephen Tong 1 2 , Anthea Lindquist 1 2 , Roxanne Hastie 1 2
  1. Department of Obstetrics, Gynaecology and Newborn Health, University of Melbourne, Parkville, VIC, Australia
  2. Mercy Hospital for Women, Heidelberg, VIC, Australia
  3. The Royal Women’s Hospital, Parkville, VIC, Australia

Introduction: Metformin is increasingly prescribed during pregnancy, yet long-term outcomes for children exposed to metformin in-utero are poorly described.

Aim: To determine whether metformin prescription in pregnancy is associated with childhood developmental vulnerability among 4–6-year-olds.

Methods: We used population-level pregnancy and birth data from 2009-2020 from Victoria, Australia, linked with the Australian Early Development Census (AEDC). This is a standardised national assessment of childhood development completed every three years during the first year of fulltime school (ages 4-6 years) that assesses children across 5 domains: physical health and wellbeing, social competence, emotional maturity, school-based language and cognitive skills, and communication skills and general knowledge. To balance differences between metformin exposed and unexposed pregnancies, we used inverse probability weighted regression adjustment to investigate the association between metformin in pregnancy and developmental vulnerability, defined as scoring <10th centile in at least two of the five assessed domains of the AEDC.

Results: There were 873,478 singleton births in Victoria between 2009 and 2020, of which 177,409 had linked birth and developmental outcome data, including 1,094 (0.6%) exposed to metformin antenatally. Developmental vulnerability was observed in 199 (18.2%) of metformin exposed children, compared with 24,379 (13.9%) unexposed. Following adjustment for confounders, metformin was not associated with overall developmental vulnerability among exposed offspring (adjusted relative risk 0.97 [95% confidence interval: 0.74, 1.29]), nor across any of the individual developmental domains.

Conclusion: In our cohort, metformin use in pregnancy was not associated with an altered risk of developmental vulnerability in exposed children at school entry.