The presence of pregnancy sickness may be related to human chorionic gonadotropin levels, thyroid function, and psychiatric effects. 1. Human chorionic gonadotropin (HCG) levels: The appearance and disappearance of the early pregnancy reaction coincide with the rise and fall of HCG levels. With the increase of hCG level, and the emergence of pregnancy reaction. 2. Thyroid function: Hyperthyroidism, caused by a transient decrease in free thyroid hormone after pregnancy, may also cause emetic reactions. 3. Mental influence: mental and psychological influences such as excessive stress and anxiety after pregnancy and changes in the living environment may also be the cause of pregnancy sickness. After pregnancy, most pregnant women will have different severity of the reaction of pregnancy vomiting, you can eat a light diet, eat more meals, usually in about 12 weeks after menopause will disappear on their own. Severe cases can be relieved with active treatment.