Powders of iron plus other micronutrients for home (point-of-use) fortification of foods consumed by pregnant women

Pregnant women are particularly vulnerable to nutrient deficiencies due to the requirements of the growing baby during the pregnancy. In low-income countries, many women have diets with low content of vitamins and minerals, and they participate in long hours of physical labour. They are also exposed to recurrent infections, which make nutritional deficiencies worse. Thus, lack of adequate nutrition can contribute to the poor health of these women their babies.

Iron and folic acid supplements in pregnancy are widely recommended. However, getting the supplements to the women and encouraging them to take them is particularly challenging. Micronutrient powders containing iron, vitamin A, zinc and other vitamins and minerals are usually packaged in single-use sachets and can be sprinkled onto any semi-solid food at home or in any other place where meals are to be consumed. The use of micronutrient powders to fortify foods may overcome this problem with micronutrient supplements. Micronutrient powders have already been shown to be effective in reducing anaemia and iron deficiency in young children and so may be useful for pregnant women.

This review looked at the use of micronutrient powders in pregnancy, compared with micronutrient supplements or with no additional micronutrients. We found only two studies involving a total of 1172 women, undertaken in Bangladesh and Mexico. The overall quality of evidence was judged very low (with a high risk of bias due to methodological limitations), and no evidence was available for the majority of primary and secondary outcomes of this review.

One trial compared micronutrient powders with iron and folate supplements, and the other trial compared micronutrient powders with the same nutrients but given as supplements. Overall, micronutrient powders fortification of foods had a similar effect as multiple micronutrient supplements on anaemia in mothers at or near term (very low quality evidence) or the mother's haemoglobin (Hb) at or near term. The study that compared micronutrient powders with iron and folic acid supplements reported that women were more likely to take iron and folic acid tablets than micronutrient powders. Nearly all of the review's important outcomes were not reported in the included studies. Therefore, more evidence is needed for both mother and infant health outcomes in order to adequately evaluate the use of micronutrient powders in pregnant women.

Authors' conclusions: 

Limited evidence suggests that micronutrient powders for point-of-use fortification of foods have no clear difference as multiple micronutrient supplements on maternal anaemia (very low quality evidence) and Hb at or near term. There is limited evidence to suggest that women were more likely to adhere to taking tablets than using micronutrient powders.

The overall quality of evidence was judged very low (due to methodological limitations), and no evidence was available for the majority of primary and secondary outcomes. Therefore, more evidence is needed to assess the potential benefits or harms of the use of micronutrient powders in pregnant women on maternal and infant health outcomes. Future trials should also assess adherence to micronutrient powders and be adequately powered to evaluate the effects on birth outcomes and morbidity.

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Background: 

It is estimated that 32 million pregnant women suffer from anaemia worldwide. Due to increased metabolic demands, pregnant women are particularly vulnerable to anaemia and vitamin and mineral deficiencies, leading to adverse health effects in both the mother and her baby. Despite the demonstrated benefits of prenatal supplementation with iron and folic acid or multiple micronutrients, poor adherence to routine supplementation has limited the effectiveness of this intervention in many settings. Micronutrient powders for point-of-use fortification are packed, single-dose sachets containing vitamins and minerals that can be added onto prepared food to improve its nutrient profile. The use of multiple micronutrient powders for point-of-use fortification of foods in pregnant women could be an alternative intervention to prenatal micronutrient supplementation.

Objectives: 

To assess the effects of prenatal home (point-of-use) fortification of foods with multiple micronutrient powders on maternal and newborn health.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015) and the International Clinical Trials Registry Platform (ICTRP) (31 January 2015). We also contacted relevant agencies to identify ongoing and unpublished studies.

Selection criteria: 

Randomised controlled trials (both individual and cluster randomisation) and quasi-randomised trials, irrespective of language or publication status.

The intervention was micronutrient powders for point-of-use fortification of foods, containing at least three micronutrients with one of them being iron, provided to pregnant women of any gestational age and parity. Five comparison groups were considered: no intervention/placebo, iron and folic acid supplements, iron-only supplements, folic-acid only supplements, and multiple micronutrients in supplements.

Data collection and analysis: 

Two review authors independently assessed the eligibility of studies, extracted and checked data accuracy, and assessed the risk of bias of included studies.

Main results: 

Our search identified 12 reports (relating to six studies). We included two cluster-randomised controlled trials (involving 1172 women) - these trials were considered to be at a moderate to high risk of bias due to methodological limitations. One trial is ongoing, and three studies were excluded.

Micronutrient powders for point-of-use fortification of foods versus iron and folic acid supplements

One trial (involving 478 pregnant women attending 42 antenatal care centres) compared micronutrient powders containing iron, folic acid, vitamin C and zinc with iron and folic acid tablets provided daily from 14 to 22 weeks to 32 weeks' gestation. The trial did not report on any of this review's primary outcomes: maternal anaemia at or near term, maternal iron deficiency, maternal mortality, adverse effects, low birthweight, preterm births. Nor did the trial report on the majority of this review's secondary outcomes, with the exception of maternal adherence. Adherence to micronutrient powders was lower than adherence to iron and folic acid supplements (risk ratio (RR) 0.76, 95% confidence interval (CI) 0.66 to 0.87, one study, n = 405).

Micronutrient powders for point-of-use fortification of foods versus same multiple micronutrients in supplements

One study (involving 694 pregnant women from 18 communities), compared micronutrient powders containing iron, folic acid, vitamin C, zinc, iodine, vitamin E and vitamin B12 with tablets containing the same seven micronutrients. There was no difference in maternal anaemia at 37 weeks of gestation (RR 0.92, 95% CI 0.53 to 1.59, one study, n = 470, very low quality evidence). The trial did not report on any of this review's other primary outcomes in relation to maternal iron deficiency, maternal mortality, adverse effects, low birthweight, or preterm birth. In terms of this review's secondary outcomes, the included trial did not report on the majority of this review's prespecified secondary outcomes with one exception - there was no clear difference in maternal haemoglobin Hb or near term (mean difference (MD) 1.0 g/L, 95% CI -1.77 to 3.77, one study, n = 470).

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