Early pregnancy reaction is considered to be related to the mechanism of hormone action in the body and the imbalance of the balance of mental state. First, the role of hormones refers to the highest level of HCG in the body in the early stage of pregnancy when the early pregnancy reaction is the most serious; twin pregnancies or glucose patients, the concentration of HCG in the blood increases significantly, and the occurrence of the early pregnancy reaction is also relatively significant. Second, the adrenal cortex function is low, then its corticosteroid secretion is insufficient, so that the body water and sugar metabolism disorders, nausea, vomiting and other gastrointestinal symptoms. Third, vitamin B6 deficiency can also lead to early pregnancy reaction is relatively large. Fourth, mental factors on the occurrence of pregnancy vomiting has a greater relationship, especially pregnant women on the pregnancy itself fear of psychology or aversion, can lead to increased vomiting. Fifth, usually have a history of severe dysmenorrhea, early pregnancy reaction, the symptoms of pregnancy vomiting is relatively common.