Modifiers of the effect of maternal multiple micronutrient supplementation on stillbirth, birth outcomes, and infant mortality: a meta-analysis of individual patient data from 17 randomised trials in low-income and middle-income countries

Abstract Objective To identify individual-level effect modifiers of the effect of multiple micronutrient supplementation (MMS) containing iron and folic acid (IFA) during pregnancy, compared to IFA alone, on the risk of stillbirth, infant mortality, and birth outcomes. Methods We performed an individual patient data meta-analysis. Study-specific estimates were generated, and we pooled subgroup estimates using fixed effects models. Findings We included 17 randomized controlled trials (including 112,953 pregnancies). MMS resulted in greater reductions in low birthweight (RR 0.81; 95% CI: 0.74–0.89), small-for-gestational age births (RR 0.91; 95% CI: 0.87–0.96), and six-month mortality (RR: 0.71; 95% CI: 0.60–0.86) among anemic (hemoglobin