Detailed explanation of the calculation method of women\’s safe period. Women\’s menstrual cycle is divided into menstrual period, ovulation period and luteal phase. During the safe period, it is difficult for women to get pregnant, but during the dangerous period, it is easy for contraceptive failure. Therefore, it is important to understand your own safe period. This article will introduce in detail the calculation method of female safe period. Menstrual Periods and Cycles Women\’s menstrual periods generally last 28 days, but the cycle may vary. In order to calculate the safety period, first