Therefore, in addition to ovulation and menstrual period, in theory, unprotected sex can be carried out at other times without pregnancy. The so-called safety period, but this is purely theoretical. Many people simplify it to one week before and after menstruation or two or three days before and after menstruation. Unfortunately, there are various factors that change menstrual cycle and ovulation in real life, so the safety period is absolutely unsafe:
First, the menstrual cycle, many women's menstrual cycle is not necessarily accurate, which brings difficulties to the calculation of ovulation period. Although we can generally rely on "the first 14 days of the next menstruation" to calculate, there are further factors that make this calculation unreliable, that is, ovulation is too complicated and there are too many influencing factors, such as weather changes, environmental changes, changes in residence, emotional changes and so on. Some women may ovulate when they are very excited, so ovulation is unpredictable. It is precisely because of the uncertainty of ovulation that the safe period is unsafe, because you don't know when you will ovulate. Maybe just when you think it's safe, your sexual partner will ovulate because of some slight factor. This may even happen when menstruation has just ended or is coming.
So once again: the safety period is absolutely unsafe.