Meta-analysis approach on iron fortification and its effect on pregnancy and its outcome through randomized, controlled trials

Micronutrients' deficiency is a common phenomenon among a majority of the population residing in the low- and middle-income countries (LMICs) especially among women and children. Given the widespread prevalence of micronutrients' deficiency in LMICs, iron-fortified foods could be of potential benefits for both the mother and the development of fetus. Present study aims to provide the evidence on the impact of iron fortification on hemoglobin (Hb) concentration during pregnancy and evaluates the specific maternal and pregnancy outcomes. We conducted systematic review by using search engines such as PubMed, Cochrane Library, Medline, EMbase, and secondary references. Meta-analyses were performed to calculate summary estimates on Hb during pregnancy, low birth weight (LBW), and preterm births. The weighted mean difference (WMD) and relative risk (RR) were calculated using random-effects models. Sources of heterogeneity were explored through meta-regression. Eight studies were included for the final analysis. The overall pooled estimate of Hb showed a significant increase in the fortification group compared with the control group [WMD = 4.45 g/L; 95% confidence interval (CI) = 2.73, 6.17 g/L; I2 = 83%, tau 2 = 6.80, rho <0.00001]. There has been a notable reduction in iron deficiency anemia (IDA) among pregnant women with substantial heterogeneity. Meta-regression suggests that the duration of feeding was positively associated with the effect size. Present review provides an evidence for the substantial benefits of iron fortification during pregnancy for reducing preterm births and risk of LBW. The safety, efficacy, and effective delivery of iron fortification need further research. Systematic review registration: PROSPERO International prospective register of systematic reviews - CRD42018116931.