In early pregnancy, it is normal for pregnant women to vomit or not to vomit. The symptoms of pregnancy vomiting are caused by the elevated levels of chorionic gland promoting hormones and estrogen and progesterone in the body, which is a clinical symptom, and the early pregnancy reaction is not exactly the same due to the different degree and speed of the elevated levels of these hormones and the different metabolic ability and sensitivity of pregnant women to these hormones. Although many pregnant women will have obvious symptoms of pregnancy vomiting when they are about 40 days pregnant, there are some pregnant women who are not sensitive to the elevation of these hormones and do not have obvious symptoms of pregnancy vomiting, which is also completely normal.