Global burden and significance of multiple micronutrient deficiencies in pregnancy.

Maternal mortality, low birthweight infants and childhood stunting continue to be major global public health problems, part of a recurring cycle of disadvantage. Maternal undernutrition in particular is one of the most neglected aspects of nutrition in public health. One possible low-cost public health intervention that might help address these problems is the antenatal provision of multiple micronutrient supplements. If the evidence base could be established, cost-effectiveness found to be acceptable and safety ensured, supplementation could ameliorate the impact of poor nutrition and diets, high disease burdens and the sociocultural factors contributing to these problems. There have been good studies in over a dozen countries addressing some of these issues but with conflicting results. Consequently, at least three meta-analyses have been undertaken to establish significant findings that could help guide policies and programs. They concluded that multimicronutrient supplementation improves birthweight and likely reduces the number of infants born low birthweight. Supplementation with iron-folic acid or multimicronutrients also appears to have positive longer-term impacts on the health and development of the offspring. There remain concerns about possible increased infant mortality in some populations. Given the results of the meta-analyses, cautious scaling-up of country effectiveness trials appears justified with careful monitoring and evaluation.