Staphyloma is a benign condition, but some can develop into a gestational trophoblastic tumor (erosive staphyloma or choriocarcinoma). Staph can be divided into partial and complete staph. The development of complete staphyloma, in which there is no fetal tissue and the uterine cavity is completely filled with blisters of varying sizes, may be related to the following factors: paternal origin of chromosomes, lack of vitamin A and animal fat in the diet, advanced maternal age, for example, women older than 35 and 40 years of age are more likely to have a staphyloma than younger women; the incidence of staphyloma in women younger than 20 years of age also has an There is an increasing tendency for women younger than 20 years of age to have an increased incidence of staph; women with a previous history of staph are more likely to have a second pregnancy than the average woman. Partial gravida can be combined with an embryo or fetus, with blister-like development of the placenta and fetal failure, and rarely with a full-term baby; it may be associated with irregular menstruation and oral contraceptive use, but not with age or diet. In conclusion, there are many causes of hyperemesis gravidarum, mainly related to the paternal origin of chromosomes, lack of vitamin A and animal fat in the diet, advanced maternal age (>35 years) or low age (<20 years), previous history of hyperemesis gravidarum, irregular menstruation, oral contraceptives, etc. Therefore, women should try to avoid some of these high-risk factors, especially women with a previous history of hyperemesis gravidarum must not rush to get pregnant. At least one year of contraception, because too short an interval can easily lead to another staph.