Background: Gestational diabetes mellitus (GDM) is a common pregnancy complication with significant maternal and neonatal risks. Emerging evidence suggests a potential link between GDM and micronutrient deficiencies, particularly zinc, a trace element vital for insulin function, antioxidant defense, and fetal development. During pregnancy, zinc demands increase, and deficiency may exacerbate oxidative stress and impair glucose metabolism. Although several studies report lower serum zinc levels in women with GDM, findings remain inconsistent due to variations in study design, diagnostic criteria, and regional differences. Understanding the prevalence of low zinc levels in this population is critical for informing antenatal nutritional interventions. This systematic review aims to synthesize available data on the prevalence of low serum zinc among women diagnosed with GDM.

Methods: This systematic review followed PRISMA 2020 guidelines and included studies from PubMed, Scopus, Web of Science, and Lens.org up to June 2025. Eligible studies were observational, reported serum or plasma zinc levels among women with GDM, and were published in English. Using the PICO framework, we focused on pregnant women with GDM and the prevalence of low zinc as the outcome. Two reviewers independently screened studies, extracted data, and assessed methodological quality using the JBI checklist. Pooled prevalence estimates were calculated using a random-effects meta analysis, with heterogeneity assessed through I² and Cochran’s Q. Publication bias was evaluated using Egger’s test and funnel plots, and equivalence testing compared observed prevalence to typical reference values for normoglycemic pregnancies.

Results: The review included ten studies spanning six countries with a combined sample of 4,863 pregnant women diagnosed with gestational diabetes mellitus (GDM). Most studies employed validated biochemical methods to assess zinc status, though variability in sample sizes, GDM diagnostic criteria, and zinc cut-offs introduced heterogeneity. Meta analysis using a random-effects model revealed a substantial pooled prevalence of low serum zinc among women with GDM, with notable variations across regions. Subgroup analyses suggested higher prevalence rates in low- and middle income countries and among studies using older GDM diagnostic criteria. Sensitivity analyses confirmed the robustness of the overall findings, although publication bias could not be entirely excluded.

Conclusion: This systematic review demonstrates that low serum zinc is a prevalent condition among women with gestational diabetes, particularly in resource-limited settings. The findings underscore the potential role of zinc deficiency in the pathophysiology of GDM and support the inclusion of zinc assessment as part of routine antenatal care. While the pooled prevalence indicates a consistent global pattern, heterogeneity among studies highlights the need for standardized diagnostic protocols and better-controlled research