This review summarizes current knowledge on the effectiveness of prenatal nutrient supplements ranging from iron-folic-acid (IFA), which is standard of care in many parts of the world, to more novel ones such as w–3 fatty acids and probiotics in improving maternal and child health outcomes. Randomized controlled trials have shown that prenatal IFA supplements reduce the risk of anemia and iron deficiency during pregnancy and at term, but the evidence of risk reductions in low birth weight (LBW) and preterm delivery (PTD) is weak. Recent studies, however, suggest that prenatal IFA supplements may reduce child mortality. On the other hand, there is convincing evidence that multiple micronutrient supplements containing 1–2 recommended daily allowances of several vitamins and minerals are safe and reduce the risk of LBW by 19 and 17% when compared to a placebo or routine IFA. Prenatal calcium supplements ( 1 1 g/day) have also been shown to significantly reduce the risk of preeclampsia and maternal death or serious morbidity by 52 and 20%, respectively. Zinc and fish oil supplements containing w–3 fatty acids may also increase gestational age and reduce the risk of PTD, but not of LBW, in selected populations. There is, however, limited evidence to support the provision of supplements containing only vitamin A, D or antioxidants such as vitamins C and E. Although the protective effect of folic acid during the periconceptual period in reducing neural tube defects is well established, very few or no intervention trials have evaluated the independent effects of specific B vitamins (vitamins B 6 , B 12 and folic acid), docosahexanoic acid and probiotics during pregnancy. The effects of prenatal iodine supplements in areas with mild to moderate iodine deficiency have not been examined either. Some of these nutrients may not affect outcomes such as PTD or LBW but may have long-term benefits for offspring health and development.