During pregnancy an increase occurs in the prevalence and density of Plasmodium falciparum malaria. The increase relative to non-pregnant women remains fairly constant with age though there is an over-all decrease in prevalence and density in both groups with age. The increase is at a height relatively early in pregnancy and declines after mid-term. At the height of the malaria season in The Gambia less antimalarial antibody appears in cord bloods than in the early dry season when transmission is lower. Infants show an increase in malaria prevalence and density in the early dry season as compared to the mid-wet season while the remainder of the population shows a decrease.