You can only get pregnant if you ovulate, but it is not possible to fully predict the danger and safe periods in the case of early and delayed ovulation days or irregular periods. In order to get pregnant, the sperm and egg need to combine in the fallopian tube and reach the uterine cavity, where the embryo is deposited in the uterine lining. Ovulation is because the egg will be discharged at this time, and at this time, if the semen enters the uterine cavity, it can easily combine with the egg, so it will have a higher pregnancy rate. However, some women have irregular periods, so there is no such thing as safe period and dangerous period, because it is impossible to determine the day of ovulation and the period of ovulation. However, some women who have regular periods may occasionally ovulate earlier or later, and this unexpected change in time can lead to pregnancy during the danger period if they happen to have unprotected sex. Therefore, in order to avoid unwanted pregnancy you need to take proper contraceptive measures, such as wearing condoms and taking birth control pills.