We examined the effect of three types of prenatal supplements containing different amounts of iron on haemoglobin (Hb) and iron status (zinc protoporphyrin [ZPP] and soluble transferrin receptor [sTfR]) in late pregnancy among 1,379 women in rural Malawi. Participants were recruited at ≤20 gestational weeks (gw) and randomly assigned to consume daily (1) 60-mg iron and folic acid (IFA); (2) 20-mg iron plus 17 micronutrients in a capsule (MMN); or (3) lipid-based nutrient supplement (LNS; 118

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... l) with 20-mg iron plus 21 micronutrients, protein, and fat. We analysed differences between intervention groups in mean Hb, ZPP, and sTfR at 36 gw, and the proportion with anaemia (Hb < 100 g L-1 ) and iron deficiency (ZPP > 60 μmol mol-1 haem or sTfR > 6 mg L-1 ) at 36 gw. Women in the IFA group had higher Hb at 36 gw than women in the LNS group (P = 0.030) and higher iron status (lower ZPP and sTfR) than women in both the LNS (P < 0.001 for both ZPP and sTfR) and MMN (P = 0.025 and P = 0.046) groups. Results for anaemia and iron deficiency showed similar trends. Further research is needed to elucidate the appropriate amount of iron to improve Hb and iron status, while improving birth outcomes.