Placental Pathologies – Intrauterine Infections

Microorganisms reach the placenta by ascending from the maternal vaginal vault, by hematogenous spread from the mother's circulation, or by direct trauma to the amniotic sac or placenta. Acute chorioamnionitis is initially a maternal response and is the morphological hallmark of ascending infections, most commonly caused by bacteria and Candida species. Acute villitis with villous microabscesses may be seen in hematogenous spread of bacterial infections and severe ascending infections. The initial fetal response is generally evidenced umbilical vasculitis.