If a woman’s menstrual cycle is regular, averaging 28-30 days, the first 7 and last 8 days of her period are usually considered safe; if the menstrual cycle is erratic, it is impossible to project a safe period. The female menstrual cycle consists of the menstrual phase, the proliferative phase, the ovulation phase and the luteal phase. The safe period is the period when there are no mature follicles and the chances of pregnancy during sex are low. The luteal phase is the period just after menstruation until ovulation, and the period after ovulation until the next menstrual period. However, since ovulation is affected by many factors, even if you have intercourse during the safe period, without contraception, some women may still be pregnant, so the safe period is not absolutely safe. Therefore, for women who do not want to get pregnant at the moment, it is not recommended to use the safe period contraception, must be good contraceptive measures.