Placental changes associated with fetal outcome in the Plasmodium coatneyi/rhesus monkey model of malaria in pregnancy.

Term placentas collected surgically from seven Plasmodium coatneyi-infected rhesus monkeys, one abortion, and five controls were evaluated histopathologically. The placentas from Plasmodium-infected dams had more significant pathologic changes than those from controls for six parameters (P < 0.05) and higher numbers of activated (LN5 + Zymed) macrophages in the intervillous space (IVS) (P = 0.0173). Total parasite load (TPL) was defined as the sum of all weekly peripheral infected red blood cell counts for each trimester and for the entire pregnancy. High first trimester PLs were more likely to result in fetal demise (P = 0.0476) or increased placental damage in surviving infants. As trimester 2-3 TPL increased, so did the number of activated macrophages (P < 0.05) and the total malaria pigment scores (P < 0.05). Low birth weight (LBW) and intrauterine growth retardation (IUGR) were associated with high pigment scores and high numbers of activated macrophages in the IVS. High placental damage scores were not associated with IUGR, LBW, or early infant mortality.