“You can’t get pregnant if you have sex during the safe period, right?” I believe this is a topic of concern for many young people who want to take advantage of the safe period to “vacuum up” and have fun while still being able to successfully prevent pregnancy. That’s really naive, safe period contraception is actually one of the most unreliable methods of contraception, and there is even a fluke of luck. And it’s only for people who have normal menstrual cycles, live together for a long time, and can correctly calculate the safety period! First of all, let’s talk about what is the safe period? The safety period is divided into the pre-ovulatory safety period and the post-ovulatory safety period. The period from the day your period clears to the day before ovulation begins is the pre-ovulatory safety period. From the first day after ovulation to the day before the next menstrual period is the post-ovulatory safety period. Some women are deceived by the safety period because it is sometimes affected by health conditions, environmental changes and mood swings that delay or advance ovulation, so the ovulation period projected by menstrual cycle is not accurate enough and can easily lead to miscalculation. According to foreign statistics, the failure rate of contraception using the method of calculating ovulation by the menstrual cycle is as high as 14.4% to 47%. Therefore, the safe period calculation method is really not reliable and not suitable for all women. Especially those who roughly use the “before seven after eight” or “before three after four” calculation of friends should be more careful, this algorithm is easy because of miscalculation and lead to a safe period “in the lottery The “lottery”. Therefore, we must remember that the safe period is not absolutely safe, when the female ovulation day appears early or delayed, the calculation of the safe period will be wrong, the chances of pregnancy during the safe period will also be greatly increased. In addition, women who are irregular in their daily lives, love cold and spicy food, often stay up late, and have sudden health problems can cause the safety period to advance or delay, making the safety period calculation accuracy greatly reduced, so the safety period to achieve the effect of contraception, only for those women who have a regular menstrual cycle, regular routine, and long-term living together with sexual partners, will be more suitable to use the safety period. It would be relatively more suitable to use the safe period to implement contraception. References: [1] What is meant by “safe period” and is it always safe to have intercourse without pregnancy [J]. Dietary Health. 2020,7(8):258 [2] Male physicians. Is birth control safe during the safe period [J]. Popular Health.2016,4:120 [3] Chen Yimin,Li Chao. Do you know how to calculate the safe period [J]. Health Expo. 2018(8)