Drugs that delay menstruation generally do not produce side effects when used occasionally, but have certain side effects if taken frequently or in large quantities. Because the drugs that delay menstruation are generally progestin-based drugs, such as progesterone and dydrogesterone, women may experience nausea, vomiting and other gastrointestinal discomfort after taking them, as well as headaches, dizziness, or menstrual disorders such as prolonged menstrual cycles and irregular bleeding. Therefore, medications to delay menstruation should not be taken frequently by women. If you need to delay your menstruation due to special circumstances, occasional use 1-2 times will not cause adverse effects on your body. When using them, you must follow the doctor’s instructions and take them according to the course of treatment in order to delay menstruation and reduce the occurrence of side effects. In addition, when women take drugs to delay menstruation, they should take them in the second half of the menstrual cycle to get good results, and must be taken under the guidance of a doctor.