The exact cause of hyperemesis gravidarum is unknown, and it is hypothesized that it may be related to a variety of factors such as ethnic geography, diet, age, and poor egg development. There is no scientific basis for the conclusion that gravida is caused by the father. 1. Race and geography: Epidemiologic investigation found that the incidence of Asian and Latin American countries is higher, while the incidence of North American and European countries is lower. Therefore, it is hypothesized that hyperemesis gravidarum may be related to race and geography. 2. Diet: Dietary deficiencies of carotenoids, vitamin A, and animal fats significantly increase the incidence of hyperemesis gravidarum. Therefore, it is hypothesized that gravidas may be related to diet and nutritional status. 3. Age: It was found that the incidence of hyperemesis gravidarum was higher when the age was >35 years old and when the age was <20 years old. 4. Poor egg development: It is presumed that the occurrence of gravidarum is related to the fertilization of empty eggs. If the egg is not well developed, there is no genetic material in the egg cell, which is called empty egg. Under normal circumstances, only one sperm can enter the egg cell, whereas in the case of a nulliparous egg, two sperm, each carrying 23 chromosomes, can fertilize the nulliparous egg, ultimately leading to hyperemesis gravidarum. The exact cause of hyperemesis gravidarum is unknown. If hyperemesis gravidarum occurs, it is recommended to treat and follow up under the guidance of a physician to avoid delays.