Under normal circumstances, pregnancy begins when the sperm and egg meet to form a diploid fertilized egg, which eventually forms a normal placenta and fetus. The placenta is primarily attached to the wall of the mother’s uterus and provides nourishment for the growing fetus. If a mistake is made during fertilization, staph can occur. And this faulty fertilization process usually leads to abnormal formation of the placenta and further leads to abnormal embryonic development. Due to the high degree of interstitial edema, blisters of different sizes are formed, which are connected to each other in bunches and resemble grapes, hence the term staphyloma, also known as blistered fetal mass (HM). The placenta is divided into complete and partial gravidity. A complete gravida is formed when the placenta is completely composed of small blisters and fills the entire uterine cavity instead of being attached to the uterine wall in the form of a disk. Since the placenta is completely abnormal, the fetus does not develop at all. Partial gravidity is formed when the placenta is composed of small partial blisters. Because the placenta is partially abnormal, the fetus can develop, but it is usually abnormal as well. The exact cause of the occurrence of staph is not known, and the average incidence in our country is about 0.78/1000 pregnancies.