Placenta previa complicates approximately 1 in 200 deliveries. The most common presentation is painless vaginal bleeding in the third trimester of pregnancy. Although approximately half of patients are near term when bleeding first develops, preterm delivery remains a major cause of perinatal death. As with placental abruption, the treatment of placenta previa varies depending upon the condition of the mother and fetus. Chorioangiomas, the most common placental tumor, are benign hemangiomas of the fetal blood vessels.
Small tumors are usually asymptomatic and of no clinical significance.
Fetal death and malformations are uncommon complications. Metastases of malignant tumors to the placenta are exceedingly rare. Gestational trophoblastic disease is a complicated topic referring to a spectrum of pregnancy-related placental trophoblast growth abnormalities. Complete moles do not contain a fetus. The fetus of a partial mole is not viable.