Emergency contraceptive pills taken during ovulation are also effective, but there will be individual differences. Emergency contraceptive pills are also effective when taken after unprotected sex during ovulation, and can be used under the guidance of a doctor. Due to ovulation after intercourse fertilization will be more than 24 hours after ovulation, so emergency contraceptive pills should be taken as early as possible to play a certain contraceptive effect, but the contraceptive effect is not absolute, when the drug appeared after menstruation overdue for more than 1 week, but also need to rule out the possibility of pregnancy. Emergency contraceptive pills can only be effective for one unprotected sex, and you need to take contraceptive measures when you have sex again. Emergency contraceptive pills contain large amounts of hormones, and side effects such as nausea, menstrual disorders or irregular vaginal bleeding may occur after taking them, and the contraceptive effect is lower than that of conventional methods, so they are not recommended as a regular contraceptive measure. For women who do not want to have children, it is recommended to take measures such as placing a birth control ring to avoid the adverse effects of the drug on the body.