Abstract: Objective To investigate the clinical features and pregnancy outcomes of placental chorioangioma diagnosed by ultrasound. 
Methods A total of 23 pregnant women with placental chorioangioma diagnosed by ultrasound were selected as the case group. Among them, the women with the largest diameter of the tumor ≥4 cm were defined as the giant group, and the women with the largest diameter of the tumor ＜4 cm were defined as the general group. Another 60 normal pregnant women were selected as the control group. The differences in clinical features and pregnancy outcomes were analyzed. 
Results Compared with the control group, the case group had a lower spontaneous vaginal delivery rate and a higher assisted vaginal delivery rate (P＜0.05). The ultrasonic manifestations of placental chorioangioma included single or multiple medium to low echo masses that could be seen in the placental parenchymal area and at the edge of the placenta, which were often close to the insertion of the umbilical cord, with blood flow signals that could be seen in some areas. Compared with the general group, the detection rate during mid pregnancy in the giant group was as high as 100%, with high complications (P＜0.05). Compared with the general group and control group, the giant group had a lower spontaneous vaginal delivery rate, higher assisted vaginal delivery rate, higher preterm birth rate, lower birth weight, lower Apgar score, and a significant increase in NICU admission rate and hospital stay (P＜0.05). 
Conclusion Prenatal ultrasound diagnosis of giant placental chorioangioma was of great significance in predicting adverse pregnancy outcomes. 

Key words: hemangioma, chorionic villi, ultrasound