Ovulation does not occur during a woman’s menstrual period. A woman’s menstrual cycle is divided into the menstrual phase, the luteal phase, and the ovulation phase. A woman’s follicle development needs to be at the time of ovulation to mature and be normally discharged. When a woman is in her menstrual period, the follicle has not yet begun to develop and mature, and there is significant shedding of the uterine lining at this time, that is to say, there is a large amount of vaginal bleeding, and ovulation does not usually occur. There is a special case, that is, the woman’s menstrual cycle is very short, in about 20 days, it is possible to form follicles during menstruation, but this possibility is very small, so the woman in the menstrual period sex is not pregnant.