BackgroundPlacental chorioangioma is a rare disorder in pregnancy. We retrospectively reviewed the perinatal complications and long-term outcomes in pregnancies with placental chorioangioma and evaluated the factors affecting disease prognosis.MethodsWe reviewed pregnant women who delivered at our hospital in the past decade and whose diagnosis of placental chorioangioma was confirmed by pathological diagnosis. Information on maternal demographics, prenatal sonographic findings and perinatal outcomes was obtained by reviewing the medical records. In the latter part of the study, follow-up of children was conducted by phone interview.ResultsIn the 10 years from August 2008 to December 2018, 175 cases(0.17%) were identified as placental chorioangioma histologically and 44(0.04%) of them were large chorioangiomas. Nearly one-third of cases with large chorioangiomas were associated with severe maternal and fetal complications or required prenatal intervention. Although one-fifth of fetuses/newborns complicated with large chorioangiomas were lost perinatally, the long-term prognosis for surviving fetuses was generally good. Further statistical analysis revealed that tumor size and location affect prognosis.ConclusionPlacental chorioangioma may cause an unfavorable perinatal outcome. Regular ultrasound monitoring can provide the tumor characteristics which can be referred to for predicting the tendency of those complications and indicate when intervention may be necessary. It is not clear which factors lead to complications with fetal damage as the main manifestation or polyhydramnios as the main manifestation.