Multiple-micronutrient supplementation for women during pregnancy.

Systematic review and meta-analysis of pregnancy trials in women, mainly from low- and middle-income countries, with some studies from the United Kingdom. Included trials compared multiple micronutrient supplementation with iron plus folic acid, iron with or without folic acid, or placebo; HIV-infected women were excluded from the included trials.

Oral multiple micronutrient supplementation during pregnancy, generally given once daily. Formulations varied across trials but typically included iron and folic acid plus additional vitamins and minerals, often as UNIMMAP or UNIMMAP-like preparations; comparators were iron with or without folic acid or placebo.

Multiple micronutrient supplementation with iron and folic acid reduced low birthweight and small-for-gestational-age births compared with iron and folic acid alone. There were no consistent improvements for preterm birth, perinatal mortality, stillbirth, or neonatal mortality. The review concluded that the findings support replacing iron and folic acid with multiple micronutrient supplements containing iron and folic acid in settings where micronutrient deficiencies are common. Trials from the United Kingdom showed no clear differences when multiple micronutrients were compared with placebo.

Formulations, doses, and co-nutrient content varied substantially across trials, which limits direct comparability. Effects were not consistent across all maternal and infant outcomes, and placebo-controlled evidence from the United Kingdom showed no clear benefit. Outcome reporting was uneven across studies, with some trials contributing only selected endpoints.