Participation
Among the 209 women enrolled in the study, 140 (67%) had complete information, including hemoglobin concentration after 12 wk of supplementation and information on the number of tablets taken (Figure 1⇓). The major reasons for loss to follow-up were giving birth before the scheduled blood sample collection at 12 wk of supplementation and technical problems with the MEMS that resulted in loss of information on compliance. The only differences between those with and without complete data were in initial hemoglobin concentration and fundal height at baseline (Table 1⇓). Among the women with incomplete data, a fundal height higher than that of the women with complete data occurred to a similar extent in the daily and weekly supplementation groups. A lower hemoglobin concentration among the women with incomplete data occurred to a greater extent among those in the weekly group than among those in the daily group.