Chronic villitis of unknown etiology and maternal arterial lesions in preeclamptic pregnancies.

Placental lesions from 361 singleton full-term pregnancies were studied. These placentas were divided into two major groups: the study group consisting of 146 placentas from mothers with pregnancy-induced hypertension and a normotensive control group, which included 215 placentas from mothers with normal pregnancies. Each group was divided into three subgroups according to the allocation of infant's birthweight in the normal ponderal curve. A statistically significant higher incidence and severity of villous lesions was observed in placentas of mothers with pregnancy-induced hypertension when infants were over the 25th centile of the ponderal curve. Vascular lesions, i.e., absence of physiological changes in spiral arteries of the placental bed, acute atherosis and chronic vasculitis-like lesions were also more frequently observed in the hypertensive group than in controls. These placental lesions have been described in placentas of small for gestational age infants with or without maternal hypertension and in those of preeclamptic women with appropriate for gestational age infants. Since acute atherosis-like lesions have been reported in placentas of pregnant women with systemic lupus erythematosus and in rejected renal transplants, a possible maternal immunological reaction against fetal tissues could be responsible for the pathogenesis of these entities.