[Malarial infection of the placenta. Parasitologic, clinical and immunologic aspects].

Among 1,206 pregnant women tested in Franceville (Gabon), 36.4% showed a positive parasitemia as compared to 21.9% of 154 non pregnant (p less than 0.001). Increase in the incidence of parasitemia appeared at the 4th month of pregnancy with two peaks at the 5th (44.4%) and 9th months (43.6%). Of 741 placenta studied, 33% showed plasmodial pathological changes; placental lesions were associated with a decrease in mean placental weight (26 g; p less than 0.001) and birth weight (220 g; p less than 0.001). Parasitemia during pregnancy and placental changes were more frequent in 1st or 2nd parous women and were associated with a decrease of inhibitory antibody titres in mothers at delivery, and with a synthesis of specific antibodies by the foetus i.e. with a transplacental transmission of plasmodial antigens to the foetus. Maternal inhibitory antibodies were constantly detected in cord blood and this could account for the absence of plasmodium in the 1,128 cord blood samples which have been examined.