Seasonality, Malaria, and Impact of Prophylaxis in a West African Village I. Effect on Anemia in Pregnancy

The importance of malaria as a cause of anemia in pregnancy in endemic areas remains controversial. The prevalence of anemia in pregnant women following the dry (May) and the rainy (November) seasons was compared in two successive years in Bougoula village (region of Sikasso, Mali). Phase I (1992) was observational and included 172 pregnant women and 208 controls. In Phase II (1993, 174 pregnant women and 206 controls), malaria prophylaxis with proguanil (200 mg/day) and chloroquine (300 mg/week) was offered to pregnant women. A strong seasonal variation in the prevalence of moderate to severe anemia in pregnant women (hematocrit < 30%) occurred in Phase I (dry season = 8.7%, rainy season = 41.2%). This variation was present only in women of parity lower than five, and paralleled variation in parasitemia. In Phase II, the seasonal variation of anemia was suppressed in women under malaria prophylaxis (presence of antimalarial metabolites in urine), and the overall prevalence of moderate to severe anemia in pregnancy decreased by 55.5% (22.8-74.3%). We conclude that malaria is the major cause of anemia in pregnancy in this region. A high priority should be given to prevention of malaria in pregnancy.