What is the safe period, and why won't you get pregnant during it?

　　The so-called "safe period" method of avoiding pregnancy involves timing intercourse outside the fertile window—specifically, avoiding the days around ovulation when conception is most likely, based on a woman's menstrual cycle, in order to reduce the chance of pregnancy. However, the safe period is not completely reliable and there remains a risk of unintended pregnancy. If symptoms such as delayed menstruation or abnormal bleeding occur, it is recommended to seek medical evaluation promptly.

　　From a physiological standpoint, a woman typically releases one egg per menstrual cycle. The egg survives for approximately 1–2 days after ovulation, while sperm can remain viable in the female reproductive tract for 2–3 days. Therefore, the days 4–5 before and after ovulation are considered the fertile window, and the remaining days are regarded as the "safe period," during which the likelihood of conception is lower.

　　However, the safe period method has significant limitations. A woman’s menstrual cycle can be easily influenced by emotions, stress, illness, or other factors, leading to early or delayed ovulation—or even multiple ovulations. Relying solely on the safe period for contraception may result in unintended pregnancy due to miscalculation of ovulation timing, particularly among women with irregular cycles who face higher risks.

　　To estimate the safe period accurately, it is advisable to record menstrual cycles over 3–6 months to determine the approximate time of ovulation. It is also recommended to combine this method with barrier contraceptives such as condoms to improve effectiveness. Regularly monitoring changes in the menstrual cycle and adjusting safe period calculations accordingly is essential for better accuracy.