Malaria and anaemia in pregnant women in urban Zanzibar, Tanzania.

Severe anaemia in pregnancy is a major obstetric problem in malaria-endemic areas. This study reports a cross-sectional investigation of malaria infection and haematological values at delivery in 440 women from urban Zanzibar. Severe anaemia [with haemoglobin (Hb) < or = 7 g/dl] was identified in 36 women (9.3%) and mild anaemia (7 < Hb < 10 g/dl) in 269 (69.7%) while 81 women (21.0%) had normal Hb values. Malaria infection was diagnosed in 187/385 women (48.6%) on the basis of either peripheral blood examination or placental histology. Univariate analysis indicated that the proportion of women with anaemia was similar in those with (85%) and without (80%) malaria infection. However, when primigravidae were considered alone, malaria infection was significantly more frequent among anaemic women (65.2%) than in those with normal Hb values (40.0%). In the logistic regression analysis, including age, parity, education level, malaria and free serum iron as independent variables and anaemia (Hb < or = 10 g/dl) as response variable, the odds ratio (OR) for malaria infection was 1.2 (P > 0.1). However, a similar analysis indicated that malaria was significantly associated with anaemia in the primigravidae, with an OR of 3.2 (95% confidence interval: 1.1-9.6; P < 0.05). In conclusion, this cross-sectional investigation indicated that malaria plays a significant role in the determination of anaemia in primigravidae, but not in multiparae, in the urban study area.