Early pregnancy reaction is mainly related to the elevation of HCG (human chorionic gonadotropin) level in the blood, after ovulation and intercourse, HCG level has not yet risen, so there will be no early pregnancy reaction. The appearance of early pregnancy reaction is mainly related to the level of HCG in the blood, generally 7~10 days after intercourse, and generally need to reach a certain value will appear early pregnancy reaction, after ovulation intercourse blood HCG has not yet risen, will not appear early pregnancy reaction. If patients have similar symptoms, they should go to the hospital in time to find out the cause of the disease. Early pregnancy reaction varies greatly from one individual to another, for those with mild symptoms, no special treatment is needed, for those with severe symptoms, such as persistent severe nausea and vomiting, they should consult a doctor in time for treatment.