Effects of prenatal multimicronutrient supplementation on pregnancy outcomes: a meta-analysis

Abstract

N utrition plays an important role in the growth and development of the fetus. Studies of the nutritional status of pregnant women during the Dutch famine revealed increased risks of infertility, abortion, fetal intrauterine growth restriction and perinatal mortality among malnourished women.1 In many parts of the world, a similar situation exists for many pregnant women with respect to nutrition. Overall, the diet of pregnant women has been reported to be deficient in calories and micronutrients. 2 Both macro-and micronutrients are important for a woman to sustain pregnancy and for appropriate growth of the fetus.The exact mechanisms of how supplementation with micronutrients can affect pregnancy outcomes are not completely understood. Possible mechanisms for beneficial effects include a generalized improvement in the immune function of women, with a reduced incidence of infections and subsequent reduced incidence of preterm birth; 3 improved energy metabolism and anabolic processes in the mother, with a reduced incidence of fetal intrauterine growth restriction; 3 improved ability to respond to stress; 3 expansion of plasma volume secondary to fluid retention, with subsequent improvements in fetal growth; 4 improved hemoglobin levels; 5 and increased absorption of iron related to intake of vitamin C and riboflavin, with subsequent improvement in hemoglobin levels. 5Potential disadvantages include adverse interactions of micronutrients when supplied in combination; 6 enhanced or reduced absorption of one nutrient by other nutrients (e.g., interaction between iron and vitamin C, and iron and zinc); 7 deleterious effects on the fetus and the mother from overdose of any one component (e.g., vitamin A overdose); 6 and cost. 6Potential barriers include the lack of well-defined government policies on maternal health and nutrition.6 A multicomponent approach has been criticized from the standpoint that some micronutrients may be necessary, some may not be needed and some may even be harmful.2 Generalized or mass supplementation with multimicronutrients may have different effects on pregnancy outcomes depending on the underlying nutritional status of the women.On the basis of a systematic review performed in 2005, the World Health Organization currently recommends iron-folic acid supplementation for all pregnant women. 8,9 The review reported that multimicronutrient supplementation during pregnancy were more efficacious than 2 or fewer micronutrients in CMAJ ResearchBackground: Reduced intake of micronutrients during pregnancy exposes women to nutritional deficiencies and may affect fetal growth. We conducted a systematic review to examine the efficacy of prenatal supplementation with multimicronutrients on pregnancy outcomes. Methods:We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library for relevant articles published in English up to December 2008. We also searched the bibliographies of selected articles as well as clinical trial registries. The primary outcome was low birth weight; secondary outcomes were pr...

The impact of prenatal vitamin A and zinc supplementation on growth of children up to 2 years of age in rural Java, Indonesia

“…The benefits of prenatal multiple micronutrient supplementation on birth size, neonatal morbidity and mortality and later growth have also been shown in studies conducted in other developing countries (35)(36)(37)(38)(39) . In one meta-analysis, reduction of LBW was found among infants of mothers prenatally supplemented with multiple micronutrients compared with placebo or Fe and folic acid (40) , whereas other meta-analyses or reviews concluded no added benefits of multiple micronutrient or Zn supplementation on birth weight (41,42) . The interpretation of these results, in relation to ours, is that composition and dosage of micronutrients as well as the time during pregnancy when supplements are introduced are crucial for infant growth and may explain the differences seen with different micronutrient and supplementation regimes.…”

Micronutrients and the use of vitamin and mineral supplements during pregnancy and lactation

“…It is postulated that improved immune function may reduce the risk of infection thereby preventing preterm delivery; they may also improve energy metabolism and anabolic processes leading to a decrease in IUGR prevalence as well as improving the maternal response to stress (Shah and Ohlsson 2009). However, there is insufficient evidence attributing a deficiency of a specific nutrient to an adverse pregnancy outcome (Keen et al 2003).…”

A gestational diet high in fat-soluble vitamins alters expression of genes in brain pathways and reduces sucrose preference, but not food intake, in Wistar male rat offspring

“…Even though the direct translation of this research to humans is unclear, intake of multivitamin supplements during pregnancy in developed countries is likely to result in intakes greater than the recommended quantities (Shah and Ohlsson 2009). In addition, the safety and effectiveness of vitamin A and D supplementation specifically have been questioned.…”