Fig. 4

Impact of P. falciparum infections on maternal hemoglobin levels. p values were obtained from multivariate linear models adjusted by gravidity, season, HIV status, residence in a village or rural area, and place where molecular analysis was conducted. The modification of the associations by gravidity was assessed by including interaction terms into the regression models, testing for significance using a Wald test (pI) and combining the coefficients plus the interaction and the standard error by the delta method. Mag, Magude; Man, Manhica; Ilh, Ilha Josina