The effect of intermittent preventive treatment of malaria during pregnancy and placental malaria on infant risk of malaria.

Background Intermittent preventive treatment of malaria during pregnancy (IPTp) with dihydroartemisinin-piperaquine (DP) provides greater protection from placental malaria than sulfadoxine-pyrimethamine (SP). Some studies suggest placental malaria alters the risk of malaria infection in infants, but few studies have quantified the effect of IPTp on infant susceptibility to malaria. Methods Infants born to pregnant women enrolled in a randomized clinical trial comparing IPTp-SP and IPTp-DP in Malawi were followed from birth to 24 months to assess effect of IPTp and placental malaria on time to first malaria episode and P. falciparum incidence. Results In total, 192 infants born to mothers randomized to IPTp-SP and 195 to mothers randomized to IPTp-DP were enrolled. Infants in the IPTp exposure groups did not differ significantly regarding incidence of clinical malaria (IRR= 1.03; 95% CI: 0.58 - 1.86) or incidence of infection (IRR= 1.18; 95% CI: 0.92-1.55). Placental malaria exposure was not associated with incidence of clinical malaria (IRR= 1.03; 95% CI: 0.66-1.59) or incidence of infection (IRR:= 1.15; 95% CI: 0.88-1.50). Infant sex, season of birth, and maternal gravidity did not confound results. Conclusions We did not find evidence that IPTp regimen or placental malaria exposure influenced risk of malaria during infancy in this population.