For women with normal menstrual cycles, it is safer to have sex when you are about to have your period. However, some women do not have normal menstrual cycles, some may be delayed or sometimes delayed and sometimes early, in this case there is no way to calculate when the period will come, so it is not possible to calculate when the safe period is, in this case we should pay attention to take contraceptive measures every time we have sex or it will be easy to get pregnant. Moreover, women’s ovulation is also affected by many factors, such as emotions, work and environmental changes, which can lead to early or delayed ovulation.