The interaction between pregnancy and malaria attacks was investigated from 1990 to 1994 among women in the village of Dielmo, a holoendemic area in Senegal where malaria transmission is intense and perennial. Clinical and parasitological data collected during the daily follow-up of 48 pregnancies among 31 women were compared with those collected from the same women using the same methods during the year which preceded or followed their pregnancy. The parasite prevalence, mean and maximum parasite density in Plasmodium falciparum infections were significantly higher during pregnancy. The incidence rate of malaria attacks was, on average, 4.2 times higher during pregnancy than during the control period. Although most pregnancies were not associated with a malaria attack and the incidence of malaria attacks decreased as the number of previous pregnancies increased, a significant increase in risk of malaria attacks among multigravidae was noted until the fifth pregnancy.