孕妇，25岁，孕足月，住院待产。既往有葡萄胎史。妇查，阴道少量流血，腹部隆起呈悬垂状，宫底在剑突下二指，胎背位于母腹右侧，服心138次，规则，臀先露，未入盆，无宫缩，胎动正常，宫高38cm，腹围140cm，骨盆外侧正常，软产道无畸形。B超所见：宫内探及一活动胎儿，船头位 Pregnant women, 25 years old, pregnant term, hospitalized to be born. Past history of hydatidiform mole. Women check, a small amount of vaginal bleeding, abdominal bulge was suspended, the bottom of the palace in the xiphoid two fingers, fetal back in the right side of the womb, serving 138 times, rules, buttocks exposed, not into the basin, no contractions, fetal movement Normal, 38cm high palace, abdominal circumference 140cm, pelvic lateral normal, soft birth without deformity. B seen: intrauterine exploration and an activity fetus, bow position