The mechanism of emergency contraceptive pills is to inhibit ovulation of the ovaries, and at the same time, it can change the thickness of the uterine lining in order to prevent the implantation of a fertilized egg, which is the contraceptive mechanism of emergency contraceptive pills. In addition, ovulation will not occur again in the same month, if in the next month, often will resume normal ovulation. It is advisable not to take the emergency contraceptive pill as a regular contraceptive in your daily life, because the side effects of the emergency contraceptive pill are really very big. It can not only cause withdrawal bleeding after taking the pill, breaking the natural ovulation pattern of the ovaries and causing endocrine disorders, causing irregular menstruation or even menstrual disorders, but also may lead to menstrual dribbling. Therefore, it is not recommended to take emergency contraceptive pills routinely, and it is recommended to use condoms or intrauterine devices for contraception in clinical practice.