Emergency contraceptives, with their hormonal component, do cause menstrual irregularities when taken orally. However, it does not usually cause menstruation half a month early, which is a serious disruption of the cycle. It may not be menstruation, but emergency contraceptive drugs, which bring about withdrawal bleeding, caused by adverse drug reactions. It is recommended to observe for 3-7 days, as long as it ends within 7 days, it will not affect your health. However, due to the withdrawal bleeding, the next period may be delayed, so it can be observed once. In some cases, the oral emergency contraceptive pill can cause confusion in the menstrual cycle for three months. You can also observe it, but if it is frequent, you should go to the gynecology department for a hormone 6 test if possible. Depending on the situation, you can take oral medications to regulate your cycle, such as short-acting contraceptives, Eusebio and Eusebio, to restore normal menstruation.