A pregnant woman was delivered to the gynecological unit with complaints of pain in the lower abdomen and insignificant bloody discharges from the genital tracts for 3 hours. Last menstruation was 3 months ago. Vaginal examination showed that body of womb was in the 10th week of gestation, a fingertip could be inserted into the external orifice of uterus, bloody discharges were insignificant. USI showed small vesicles in the uterine cavity. What is the most likely diagnosis?