Iron plus folate supplementation increases mortality and morbidity among children in areas of malaria endemicity in Africa, but the effects of supplementation on pregnant women in malaria-endemic areas remain unclear. In northeastern Tanzania, where malaria and iron deficiency are common, we found that placental malaria was less prevalent (8.5% vs. 47.3% of women; [Formula: see text]) and less severe (median parasite density, 4.2% vs. 6.3% of placental red blood cells; [Formula: see text]) among women with iron deficiency than among women with sufficient iron stores, especially during the first pregnancy. Multivariate analysis revealed that iron deficiency ([Formula: see text]) and multigravidity ([Formula: see text]) significantly decreased the risk of placental malaria. Interventional trials of iron and folate supplementation during pregnancy in malaria-endemic regions in Africa are urgently needed to ascertain the benefits and risks of this intervention.
1Mother-Offspring Malaria Studies Project, Seattle Biomedical Research Institute, and 2University of Washington, Seattle, Washington; 3Center for International Health Research, Rhode Island Hospital, Brown University, Providence, Rhode Island; and 4Muheza Designated District Hospital, Muheza, 5Tumaini University, Moshi, and 6National Institute for Medical Research, Dar es Salaam, Tanzania.