Hemorrhagic endovasculitis of the placenta. A clinical-pathological study in Brazil.

Hemorrhagic endovasculitis (HEV) of the placenta involves damage to or destruction of chorionic vessels and fetal erythrocytes. We evaluated the frequency and extension of the HEV and clinical events and morphologic changes associated with it in placentas from liveborn and stillborn infants. Two hundred sixty four placentas were examined: 214 from livebirths and 50 from stillbirths. The livebirths were subdivided according to the time of intrauterine retention (IUR). HEV occurred in 8.8% of placentas from livebirths and in 32% from stillbirths. In the livebirths the lesion affected small number of villi, was frequently associated with villitis (73.6% of the cases), but there was no significant association with maternal disease or birth weight. In the stillbirths, HEV was strongly associated with the time of IUR. In stillbirths with 1 day of IUR, HEV occurred in frequency similar to the livebirths (9.5%), but in stillbirths with 2-7 days of IUR the frequency was high (71.4%) and numerous vessels were involved. In those over 7 days the lesion was less extensive and frequent (20%) and it had the appearance of end stage of organization. We conclude that HEV, in livebirths and fresh stillbirths is frequently a small lesion of little significance, while in macerated stillbirths it is an artifact of maceration.