Malaria is particularly harmful during pregnancy causing anemia in the mother and low birth weight which, in turn, increases infant mortality. Thus, the World Health Organization (WHO) now recommends that all pregnant women who live in malaria endemic areas of Africa should receive sulfadoxine-pyrimethamine (SP) at monthly intervals during the second and third trimesters of pregnancy. Malaria is especially severe during first pregnancies and the value of intermittent preventative treatment with SP during first pregnancies has been clearly shown. However, it is less certain whether multigravidae, who are at less risk, also benefit from intermittent preventative treatment with SP. To investigate this, a trial has been conducted in Gambian multigravidae who were given intermittent preventative treatment with SP or placebo during the second and third trimesters. The prevalence of anemia six weeks after delivery, low birth weight and poor outcome of pregnancy in women in each group were studied.