Fig. 2

P. falciparum positivity rates, parasite density and detectability by gravidity for each health clinic. Estimated Pf (P. falciparum) qPCR positivity rate and Prop (Proportion) of detectable infections for Magude, Manhiça, and Ilha Josina in primigravidae and multigravidae (A). B presents the same analysis but including primigravidae, secundigravidae and multigravidae in Ilha Josina. Estimates were obtained from multivariate regression models predicting parasitological outcome in each of the three sites based on visit date, gravidity, and their two-way interactions, adjusted by season, HIV status, residence in a village, or rural area and place where molecular analysis was conducted. The statistical significance of the interaction term (p for the interaction [pI]) was assessed using a Wald test and estimates obtained from the coefficients plus the interaction and the standard error by the delta method