The main reason is that the mechanism of contraception is to inhibit ovulation and thin the lining of the uterus to prevent the fertilized egg from being laid in order to achieve the purpose of contraception. 1 box of contraceptive pills will inhibit the growth and development of one follicle and ovulation, if you still want to contraception next month, it is recommended to take Eusebio on the 5th day of menstruation, which will play the role of contraception for another month. If you continue to use Eusebio, it is recommended that you take it again on the 5th day of your period. If you continue to use Eusebio for contraception, it is recommended that you take 1 box of Eusebio each month for the appropriate contraception. Taking Eusebio may cause a gradual decrease in menstrual flow or irregular vaginal bleeding, which will disappear with continued use. If amenorrhea occurs while taking Eusebio, normal menstruation will resume after 2 months of discontinuing the medication.