Association between Maternal Selenium Exposure and Congenital Heart Defects in Offspring: A Systematic Review and Meta-Analysis

Background: the association between congenital heart defects (chds) and selenium (se) is still unclear. we aimed to systematically review and quantitative analyze the potential relationship between maternal se exposure and chds in the offspring.methods: pubmed, embase, web of science and scopus databases were searched from inception up to au-gust 2021 for relevant studies. methodological quality of the studies was assessed through newcastle-ottawa scale. the standard mean difference (smd) and corresponding 95% confidence interval (ci) were calculated to compare maternal se levels between chds groups and control groups using a random-effects model.results: four articles covering five studies were included in the systematic review, and three articles covering four studies were included in the meta-analysis. one study measured se concentrations in maternal hair and found a positive correlation between high concentrations and increased risk of chds in offspring. however, one study on cord blood, and one on whole blood illustrated that se exposure was associated with decreased risk of chds. there was no significant association found between serum se levels and chds in two studies. pooled results showed decreased se levels in the circulation of mothers with chds offspring (smd = -108.27, 95% ci: -192.72, -23.82), with statistically significant heterogeneity (i2 = 99.8%, p < 0.001) but not in hair, as compared with controls.conclusion: low maternal se status may be associated with increased risk of chds in offspring. however, further larger-scale studies with strict and consistent design methods are still required to investigate this issue.