Micronutrient powders v iron-folic acid tablets in controlling anaemia in pregnancy

Summary of research¹

The major cause of anaemia in pregnancy is iron deficiency, which is preventable. It is estimated that 56% of pregnant women in developing countries and 18% of pregnant women in industrialised countries are anaemic. The prevalence of anaemia during pregnancy in South Asian countries is among the highest in the world. A study conducted in rural Bangladesh reported a 54% prevalence of anaemia among pregnant women during the second trimester. Similar high rates of anaemia have been reported among lower-and middle-class pregnant women in Dhaka. Although a number of national programmes have been implemented attempting to address this problem, continuing high rates of anaemia among pregnant women suggest that traditional strategies such as iron-folic acid (IFA) tablets are not effective. This limited effectiveness may be attributable to inadequate supply, low coverage, and/or poor adherence. In order to address poor adherence to standard iron drops in young children, the micronutrient powder ‘Sprinkles’, a single-serving sachet containing a blend of micronutrients in powder form, was developed. Powdered micronutrient supplements can be easily incorporated into foods prepared in the home. Several clinical trials have demonstrated the efficacy of micronutrient powders in lowering the burden of anaemia in children in the developing world. However, no study to date has examined the efficacy of this intervention against anaemia throughout pregnancy.

A recent cluster randomised trial, set out to determine whether home fortification with a micronutrient powder for pregnancy (MNP-P) is at least as efficacious as IFA tablets for improving haemoglobin concentration in pregnant women. The trial was carried out in the sub-district of Kaliganj in central Bangladesh. This is a densely populated rural area that relies primarily on agricultural labour. Participants were recruited from 42 community-based Antenatal Care Centres operated by BRAC (formerly known as the Bangladesh Rural Advancement Committee), a large non-governmental organisation founded in Bangladesh in 1972.

All pregnant women who received services at one of the Antenatal Care Centres and were between 14 and 22 weeks of gestation were asked to join the study. Gestational age was approximated by using the woman’s recall of her last menstrual period. If the number of participants enrolled from one Antenatal Care Centre did not meet the sample size requirements, the study team returned to the centre the following month and repeated the recruitment process. For logistical reasons, the researchers limited the recruitment phase to the first five months of the study period, which started in October 2005 and ended in March 2006. Women did not meet the eligibility criteria if they were severely anaemic (haemoglobin < 70 g/L), had a haemoglobin concentration greater than 140 g/L, were at more than 22 weeks of gestation, or were already taking iron supplements prior to the start of the study. The primary reason for declining to participate in the study was unwillingness to provide a blood sample for haemoglobin assessment. A total of 779 pregnant women from 42 clusters were identified. Out of this population, 478 women met the eligibility criteria and were randomized, at the cluster level, to the MNP-P group (21 clusters, n = 243) or the IFA tablet group (21 clusters, n = 235). Each cluster consisted of approximately 300 households, and the number of women per cluster ranged from 3 to 26. The primary reasons for exclusion at baseline were gestational age greater than 22 weeks (15.8%), recent use of iron supplements (11.3%), pregnancy loss (4.4%), and planned move out of the study area (2.2%). Two women were excluded because they had severe anaemia (haemoglobin < 70 g/L), and 12 were excluded because they had haemoglobin levels above 140 g/L.

A single Antenatal Care Centre typically serves one village or population of approximately 300 households. Each Antenatal Care Centre was defined as a cluster, and each cluster was randomly allocated to receive either MNPP (60 mg of elemental iron, 400 µg of folic acid, 30 mg of vitamin C, and 5 mg of zinc) or IFA tablets (60 mg of elemental iron and 400 µg of folic acid). The iron dose corresponded to recommendations for areas in which the prevalence of anaemia is above 40%, and the dose of folic acid administered was based on the amount of synthetic folic acid recommended for prevention of neural tube defects. Both interventions were administered daily, starting at the first study visit and lasting until 32 weeks of gestation. Those assigned to the MNP-P group were instructed to sprinkle the full contents of a package into any semi-solid or semi-liquid food when the food was at room temperature.

Changes in haemoglobin from baseline were compared across groups using a linear mixed-effects regression model. At enrolment, the overall prevalence of anaemia was 45% (n = 213/478). After the intervention period, the mean haemoglobin concentrations among women receiving the micronutrient powder were not inferior to those among women receiving tablets (109.5 ± 12.9 vs 112.0 ± 11.2 g/L; 95% CI, -0.757 to 5.716). Adherence to the micronutrient powder was lower than adherence to tablets (57.5 ± 22.5% vs 76.0 ± 13.7%; 95% CI, -22.39 to -12.94). However, in both groups, increased adherence was positively correlated with haemoglobin concentration.

Focus group discussions to explore the reasons for nonadherence found that non-adherent women in the MNP-P group expressed concern that adding Sprinkles to their daily food would worsen the nausea associated with pregnancy. However, a few women also mentioned that Sprinkles increased their appetite. Given that food was generally scarce, increased appetite was not a positive attribute of the intervention

Overall, the findings suggest that despite lower adherence, the relative efficacy of MNP-P and IFA tablets was similar when they were started in the second trimester of pregnancy. However, the interpretation of results is limited to ‘relative’ comparisons, since the randomized design did not include a non-intervention group.

Given the limited number of studies on MNP use during pregnancy, it is also difficult to assess the effectiveness and feasibility of this approach in a programme setting. In fact, recently published World Health Organization (WHO) guidelines on the use of MNPs during pregnancy recommend against this intervention as an alternative to iron and folic acid supplements due to a lack of evidence on its potential benefits and harm. The guidelines also state, however, that current supplementation and mass food fortification approaches do not always work because of difficulties in implementation or reaching target populations. There has been growing interest in alternative strategies for providing micronutrients to pregnant women in low- and middleincome countries, and WHO has recommended that future research be conducted to evaluate the effectiveness of MNPs as one such strategy. Considering the findings from this study, the authors suggest that further research on factors related to MNP adherence that addresses culturespecific food preferences would be of particular benefit. It is possible that simply having a choice between tablets or MNP-P might improve overall adherence to iron and folic acid interventions among pregnant women.

¹Choudhury et al (2012). Relative efficacy of micronutrient powders versus iron-folic acid tablets in controlling anaemia in women in the second trimester of pregnancy. Food and Nutrition Bulletin, vol. 33, no. 2, pp 142-149, 2012