The importance of the period of malarial infection during pregnancy on birth weight in tropical Africa.

Malaria in pregnant women is related to low birth weight (LBW), a factor contributing to infant mortality. Which period of infection during pregnancy leads to the most harmful consequences is unclear. We analyzed data collected in Burkina Faso for 1190 pregnant women. Birth weight was analyzed through multivariate linear and logistic regressions. Infection after 6 months of pregnancy was related to a decrease in mean birth weight (-105 g, P = 0.02) and a higher risk of low birth weight (AOR = 1.8, P = 0.02). A trend was found between infection before 4 months of pregnancy and a decrease in birth weight (-68 g, P = 0.08). This suggests that the end of pregnancy is the most important period in terms of public health, but infection at the beginning of pregnancy may also have consequences. Malaria prevention policies should be started early in pregnancy, especially by implementing the systematic use of insecticide-treated nets.