Prenatal multiple micronutrient supplementation has greater impact on birthweight than supplementation with iron and folic acid: a cluster-randomized, double-blind, controlled programmatic study in rural Niger

Abstract

Background: Micronutrient deficiencies during pregnancy are associated with adverse pregnancy outcomes, including reduced birthweight. Low birthweight is associated with increased risk of infant mortality and growth failure.

Objectives: To assess the effects of prenatal supplementation with UNIMMAP (United Nations International Multiple Micronutrient Preparation) compared with iron/folic acid on average birthweight and incidence of low birthweight.

Methods: Pregnant women from 78 villages in Niger were included in a cluster-randomized, double-blinded, controlled supplementation trial. Baseline, monthly follow-up, and birth data were collected. Cluster analysis was conducted to assess differences in mean birthweight and incidence of low birthweight between groups using multiple linear regression models. Analyses were stratified by nutrition status and duration of supplementation.

Results: Of the 3,670 women recruited, 2,550 completed the study and provided complete birthweight data (1,328 received multiple micronutrients and 1,222 received iron/folic acid). Mean birthweight was significantly higher (67 g, p < .001) with multiple micronutrients (3,092 +/- 190 g) than with iron/folic acid (3,025 +/- 205 g); this corresponded to a 14% fall in the incidence of low birthweight (from 8.4% with multiple micronutrients to 7.2% with folic acid fortification). The impact of multiple micronutrients was greater when the supplements were taken for more than 150 days. The incidence of low birthweight was further reduced in women who entered pregnancy with a poorer nutrition status.

Conclusions: Prenatal supplementation with multiple micronutrients had a greater positive impact on birthweight than supplementation with iron/folic acid. Our data suggest that prenatal supplementation with multiple micronutrients as part of a prenatal care package in addition to interventions to promote improved maternal prepregnancy nutrition status is an important strategy to increase birthweight and reduce the incidence of low birthweight.