GESTATIONAL diabetes mellitus (GDM) affects around 14% of pregnancies worldwide and is characterised by impaired glucose regulation that typically resolves postpartum. Although the link between Type 2 diabetes and increased breast cancer risk is well established, the relationship between GDM and breast cancer has remained unclear. A newly published systematic review and meta-analysis seeks to clarify this association, drawing on global data to determine whether GDM influences long-term breast cancer risk. The key finding is that while no significant overall link was observed, marked differences exist across regions.
To investigate this relationship, researchers systematically searched five major databases up to April 2025, including PubMed, EMBASE and the Cochrane Library. Eligible studies were screened and assessed for quality using the Newcastle-Ottawa Scale. Data from cohort and case-control studies were extracted by two independent reviewers. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using fixed- or random-effects models depending on the degree of heterogeneity, assessed using the I² statistic. Subgroup, sensitivity, and publication bias analyses were also performed using STATA 17.
Results showed no statistically significant association between GDM and breast cancer risk overall (hazard ratio [HR]: 1.03; 95% CI: 0.92–1.15). However, regional subgroup analyses revealed opposing trends: in North America, GDM was associated with a reduced risk of breast cancer (HR: 0.89; 95% CI: 0.84–0.95), while in Asia, GDM was linked to an increased risk (HR: 1.23; 95% CI: 1.15–1.31). No significant associations were found when stratifying by study design or follow-up duration. Sensitivity analysis confirmed the robustness of findings, and there was no evidence of publication bias.
This study offers reassuring news for clinicians and patients in many settings, suggesting that GDM does not confer a global increase in breast cancer risk. However, the regional variation uncovered underscores the need for context-specific follow-up strategies and further research into genetic, environmental, and healthcare system factors that may mediate this risk. Limitations include the reliance on observational data, potential residual confounding, and the lack of mechanistic insight. Clinicians should remain vigilant, particularly in Asian populations, and consider tailoring postnatal screening and education accordingly.
Reference
Li J et al. Association between gestational diabetes mellitus and risk of breast cancer: a systematic review and meta-analysis. Front Endocrinol (Lausanne). 2025;16:1621932.