Effect of gestational diabetes mellitus on maternal serum uric acid levels: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to investigate the effect of gestational diabetes mellitus (GDM) on maternal serum uric acid (SUA) levels. METHODS: We searched PubMed, Embase, Web of Science, Scopus and the Cochrane Library from inception to 31 January 2025. Cohort and case-control studies reporting SUA at or before 28 weeks' gestation and subsequent GDM were eligible. Random effects meta analyses with Hartung-Knapp adjustment synthesised. RESULTS: Sixteen studies (19 reports) encompassing 25 212 GDM cases and 148 519 normoglycaemic controls met all criteria. In eight studies with continuous data (2 690 GDM vs. 6 250 controls), women who developed GDM had an average first trimester SUA 44.3 µmol L⁻¹ higher than controls (95% CI 10.3-78.3; I²=96.9%). Ten studies providing categorical estimates yielded a pooled adjusted OR of 2.35 (95% CI 1.54-3.58; I² = 98.7%), indicating a > two fold risk of GDM with elevated SUA. However, substantial heterogeneity was observed across studies (I² >95%). Sequential omission of individual studies, alternative τ² estimators and restriction to high quality cohorts all preserved statistical significance. Funnel plot asymmetry suggested mild small study effects for categorical data but trim and fill adjustment changed the OR by < 10%. CONCLUSIONS: Elevated SUA measured as early as the periconceptional period is consistently associated with an approximately two fold increase in GDM risk. Given its low cost and routine availability, first trimester SUA may hold promise as an adjunctive early pregnancy risk stratification tool, though further validation studies are needed to confirm its clinical utility.