Relationship between iron metabolism and gestational diabetes mellitus: A systemic review and meta analysis.

To investigate the relationship between serum iron metabolism indexes and gestational diabetes mellitus (GDM) using a meta-analysis.Databases including PubMed, Web of Science, Embase, and Cochrane Library were searched. Prospective cohort or case-control studies evaluating the relationships between serum iron metabolism indexes and GDM were retrieved from these data-bases. The outcome indicators, such as mean ± standard deviation, relative risk (RR), or odds ratio (OR) were extracted. The RR or OR, standard mean difference (SMD), and 95% confidence interval (CI) were used to calculate the combined effect sizes.A total of 32 studies on the relationships between serum iron metabolic indexes and GDM were included. The serum iron [SMD=0.40 mg/dL, 95% CI (0.16, 0.64), p=0.001], ferritin [SMD=0.58 ng/mL, 95% CI (0.35, 0.81), p˂0.001], hemoglobin [SMD=0.48 g/dL, 95% CI (0.28, 0.67), p˂0.001], transferrin saturation [SMD=0.83%, 95% CI (0.15, 1.52), p=0.000], and hepcidin [SMD=0.63 ng/mL, 95% CI (0.09, 1.18), p=0.023] levels were higher in the GDM group than in the non-GDM group, whereas total iron binding ability [SMD = -0.53 μg/dL, 95% CI (-1.05, -0.02), p=0.001] was lower in the GDM group than in the non-GDM group. High serum ferritin [OR=1.92, 95% CI (1.59, 2.32), p˂0.001] and hemoglobin levels [OR=1.30, 95% CI (1.04,1.63), p=0.023] were associated with GDM risk.Serum iron, ferritin, transferrin saturation, hepcidin, and hemoglobin levels were higher and total iron binding ability was lower in GDM patients than in those without GDM. High serum ferritin and hemoglobin levels were associated with GDM risk.