PLACENTAL MALARIA AND LOW-BIRTH-WEIGHT NEONATES IN URBAN SIERRA-LEONE

The birthweights of 768 singleton neonates were assessed in a study ca rried out over a 3-year period among indigenous, paturient women in Fr eetown, where malaria is mesoendemic. About 18.5% of placentae were fo und infected with malaria and the dominant species was Plasmodium falc iparum. The proportion of low birthweight (LBW) babies from infected p lacentae (22.5%) was significantly greater than the proportion from th e uninfected (P < 0.01) and, among the infected, the proportion from p rimiparae (38.9%) was significantly greater than that from the multipa rae (P < 0.05). The mean weight of babies from infected mothers was 26 5 g lower than that of babies from uninfected mothers (P < 0.001) and the babies of primiparae were, on average, 156 g lighter than those of the multiparae (P < 0.001). Although infection significantly lowered mean birthweight in both parity groups (P < 0.001), the reduction was larger in the primiparae (294 g) than in the multiparae (240 g). The L BW risk ratio for primiparae compared with multiparae was 2.3 for both infected and uninfected groups. The proportions of attributable risk indicated that parity accounted for about 57% of all cases of LBW in p rimiparae, irrespective of infection. Infection enhanced the risk of p roducing LBW babies in the primiparae by 11.6%. LBW frequency and rela tive risk were inversely related to parity of mothers and were higher for infected placentae.