The term “great aunt” refers to menstruation. Generally, the 10 days before menstruation is the safe period, but there are individual differences. Women who have regular menstrual cycles ovulate about 14 days before their next period, and the 4-5 days before and after ovulation are fertile, but the rest of the time is considered safe, so 10 days before menstruation is also a safe period, but due to a variety of factors such as emotional, psychological and other factors that affect the time of ovulation, it is not absolutely reliable, so there are also individual differences. For women who do not have childbearing requirements to take safe period contraception is not very reliable, the risk of contraceptive failure is greater, so it is recommended that under the guidance of a doctor to choose a safe and reliable method of contraception, such as placing intrauterine devices, condoms, short-acting contraceptives, etc., in order to avoid the occurrence of an unplanned pregnancy.