How to judge that the fetal membranes have been expelled can be roughly judged according to the degree of integrity of the placenta, the situation of bad dew, the presence of symptoms of infection and other manifestations, and sometimes it is necessary to use ultrasound to further judge and intervene to help expulsion. I. Routine delivery: 1, the degree of integrity of the placenta: after the delivery of the placenta, the midwife will carefully check whether the membranes are aligned and complete, and if the placenta can be completely covered, it means that the membranes have been eliminated cleanly; 2, the situation of bad dew: if the bad dew is delayed or continues to be bloody, then it is necessary to consider that there are remnants of the placenta and fetal membranes; 3, the symptoms of infection: if the mother has abdominal pain, the vaginal secretions have a strange odor, and there is a painful sensation when she presses the lower abdomen, then it means that the placenta, the fetal membranes, the placenta, the fetal membranes and other symptoms, then it means that there is a residual infection. Symptoms: if the mother has abdominal pain, vaginal discharge with strange smell, and pain when pressing the lower abdomen, it means that the placenta and fetal membranes may be retained for a longer period of time, which has caused the mother to have symptoms of infection; 4. Ultrasound: the uterine cavity can also be observed by ultrasound to see if there is any abnormal residual material in the uterine cavity. Second, special circumstances: if the mother has a history of multiple abortions or history of uterine scraping, and large-month induced termination of pregnancy history, generally the fetal membranes can not be discharged all by itself, the need for doctors to help take out the placenta and ultrasound to check the residual fetal membranes, the need for uterine surgical evacuation, and closely observe the amount of postoperative vaginal bleeding.