Maternal undernutrition is prevalent among pregnant women in low- and middle-income countries and contributes to adverse outcomes, including fetal growth restriction, low birth weight, and maternal and child morbidity and mortality. Various interventions have been tested to determine their efficacy in improving women’s nutritional status during pregnancy and birth outcomes, including food and nutrient supplementation. Lipid-based nutrient supplements (LNS) were designed to provide multiple micronutrients embedded in a food base that also provides energy, protein and essential fatty acids. This combination of macro- and micro-nutrients addresses multiple potential nutritional deficiencies and thus has the potential to reduce maternal and child malnutrition. Characteristics of individuals and of study (site) settings may modify the effect of LNS provided to pregnant and lactating women on maternal, pregnancy and infant outcomes. Identification of subgroups of women who may experience greater benefits from LNS may be useful in informing the development of public health programs and policies. This analysis has three objectives: 1) To generate pooled estimates of the effect of randomized controlled trials of LNS provided to pregnant women on maternal, pregnancy and infant outcomes. 2) To identify study site-level modifiers of the effect of LNS in the same populations and outcomes. 3) To identify individual-level modifiers of the effect of LNS in the same populations and outcomes.