There are no days during the safe period that are absolutely safe. Days 1 to 7 of the menstrual cycle and the last 4 to 5 days of the cycle are a time when eggs are dead and not ovulated, and ovulation is unlikely throughout the menstrual cycle. But the safe period is not always accurate. If the patient has irregular menstruation, endocrine disorders or diseases, it may lead to disruption of the patient’s menstrual cycle and the safe period time will be different. Contraception during the safe period is not recommended. The contraceptive rate of safe period contraception is low and inaccurate, and there is a possibility of pregnancy. The general public can not completely and correctly deduce the time of the safe period, and can not be professionally tested. Clinical failure of safe period contraception is often seen, and patients are advised to choose safer contraceptive methods.