Currently, no prospective studies have proven that anemia per se increases the risk of maternal mortality, and there is inadequate information on an established hemoglobin concentration below which the risk of mortality increases. Such a cutoff value has been suggested to be as high as 89 g/L, a concentration associated with twice the risk of maternal death in Britain in 1958 (10). Hemoglobin concentration cutoffs suggested by others (9, 11, 12) need to be substantiated. The increased risk of mortality would also be more plausible and predictable if the mechanisms involved were understood. It has been suggested that maternal deaths in the puerperium may be related to a poor ability to withstand the adverse effects of excessive blood loss (12), an increased risk of infection, and maternal fatigue; however, these potential causes of mortality have not been evaluated systematically.