Seasonality, malaria, and impact of prophylaxis in a West African village I. Effect of 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.

Seasonality, malaria, and impact of prophylaxis in a West African village. II. Effect on birthweight.

The impact of malaria on low birthweight was investigated in Bougoula village (Sikasso region, Mali). In two successive years, pregnant women were followed until delivery. Phase I (1992) was observational, with 135 complete observations. Phase II (1993) included 126 participants, who were offered malaria prophylaxis with proguanil (200 mg/day) and chloroquine (300 mg/week). The results show that 1) infants of first and second pregnancies had lower birth weights (-382.7 +/- 62.6 g; P < 0.0001) compared with higher rank pregnancies; 2) strong seasonal variation in birthweight was observed in Phase I, with an annual cycle, a nadir in January, and an amplitude of 372.4 g (P = 0.0002); 3) parasitemia measured during pregnancy was associated with lower birthweight in infants from first and second pregnancies, but not from higher parity mothers; and 4) malaria prophylaxis taken for 20 weeks or more in Phase II suppressed the seasonal variation of birthweight and the effect of low parity (+423.4 +/- 118.8 g; P = 0.0004). We conclude that malaria in pregnancy has an important negative impact on birthweight in first and second pregnancies. Prophylaxis with proguanil and chloroquine is an effective prophylaxis when taken for 20 weeks or more.