How much Antenatal Supplemental Iron is Required to Preserve Maternal Iron Status? The MINIMat Intervention trial in Bangladesh

Abstract

Objectives: To prevent iron deficiency in pregnancy universal iron folic acid supplementation is recommended by WHO. We aimed to compare the effect of multiple micronutrients supplements with two different dosages of iron/folic acid supplements on maternal iron status. Methods: In the MINIMat intervention trial in Bangladesh, pregnant women were randomized into three micronutrient supplementation groups: 30 mg iron/400 ugfolic acid (Fe30 F), 60 mg iron/400 ugfolic acid (Fe 60 F) and multiple micronutrients +30 mg iron/400 ugfolic acid (MM). Adherence was electronically monitored by use of eDEM-pillbottles. Plasma-ferritin (p-Ft) was assessed at start of supplementation (week 14) and at week 30 at gestation in random subset. Intent to treat and multivariate regression analyses were performed (n=561). Results: Iron deficiency (ID) was 7% at start of supplementation. At wk 30 ID was 29% and mean p-Ft 20.0 ug/L with no differences according to supplementation type. Within each type there was a significant dose-effect per capsule on p-Ft that did not differ between types when amount of iron in the supplements was taken into consideration. There was no further dose-effect on p-Ft of iron intake exceeding 4 g. Using lowest tertile of iron intake as reference, middle and highest intake tertile increased p-Ft and showed a protective effect on ID at wk30 but did not differ between each other. Conclusions: Despite no further effect on p-Ft of higher iron intake than 4 g, ID developed to become prevalent at wk 30 suggesting that iron intake exceeding 4 g contributes to limited extent to reduce ID in pregnancy. Supplement with multiple micronutrients did not provide any additional effect.