TRANSPLACENTAL TRANSMISSION OF PLASMODIUM-FALCIPARUM IN RURAL MALAWI

Malaria during pregnancy may result in fetal exposure to malaria when parasites are transmitted across the placenta. To document the rate of transplacental passage of Plasmodium falciparum and to identify the r isk factors for congenitally acquired malaria infection, we examined u mbilical cord blood for malaria parasites from 2,080 newborn infants b orn to mothers enrolled in a study of malaria prophylaxis during pregn ancy. Cord blood parasitemia was detected in 140 (6.7%) newborn infant s with a geometric mean density of 187 parasites/mu l (range 12-99,752 parasites/mu l). The likelihood of umbilical cord blood parasitemia w as closely linked to the parasite density of placental malaria infecti on and the density of maternal peripheral blood parasitemia at the tim e of delivery; all babies born to women with both placental and periph eral blood parasitemia densities greater than or equal to 10,000/mu l had cord blood parasitemia. In a multivariate logistic regression mode l, male sex, premature delivery, and placental and maternal peripheral blood malaria parasitemia were independently associated with a baby b eing born with umbilical cord blood parasitemia. In this setting, high ly endemic for malaria, transplacental transmission of malaria from in fected placentae occurs frequently and is directly related to the dens ity of maternal malaria infection.