Evaluation of Selenium Status among Iranian Pregnant Women: A Systematic Review and Met-Analysis

Selenium (Se) plays an important role in numerous immunological functions of human health. It has been shown that maternal Se deficiency contributes to many pregnancy complications such as pre-eclampsia, gestational diabetes mellitus (GDM), miscarriage, and even fetal growth restriction. Due to the evidence of importance of Se in pregnancy outcomes and the inconsistency of current shreds of evidence on Se adequacy in Iranian pregnant women, this study aimed to provide a comprehensive evaluation of published studies. This systematic review explored studies reporting dietary Se intake, serum or plasma Se, and Umbilical cord Se in Iranian pregnant women. Methods: PubMed, Scopus, Web of Science, Embase, Google scholar (in English and Persian), and Persian databases, including Scientific Information Database, IranDoc, Iranian National Library, Magiran, and Regional Information Center for Science and Technology, were reviewed. Results: A total of 30 studies were included in the meta-analysis. Pooled effect sizes show an overall value of 90.09 µg/l (95% CI: 81.89, 98.29) and 75.08 µg/d (95% CI: 63.01, 87.16) for serum and dietary Se. Geographically, the lowest serum Se was in Fars and East-Azerbaijan with values of 61.97 µg/l (51.38, 72.55) and 55.12 µg/l (48.5, 61.74), respectively. Dietary intake pooled estimate showed that the lowest Se intake was in West-Azerbaijan with a value of 42.80 µg/d (95% CI: 38.95, 46.65). Conclusion: The current study shows that the overall serum and dietary intake of Se in Iranian pregnant women is acceptable. Some parts of the country need monitoring to prevent Se inadequacy and related-adverse complications in pregnant women.