Ovulation does not occur during menstruation. Menstruation is a normal physiological phenomenon that usually lasts for 3-7 days. The majority of women have a menstrual cycle of 28-30 days, and ovulation occurs basically 14 days before the next menstrual period, so ovulation will not occur during menstruation. However, in some cases, if there are abnormalities in menstruation, such as prolonged menstruation, which takes about 12 days to clear clinically, ovulation may occur during menstruation, coupled with the shortening of the menstrual cycle itself, so it is necessary to analyze the case clinically with a combination of the clinical history, menstrual cycle, and menstrual cycle to know whether ovulation occurs during the menstrual period. Ovulation can be detected during the menstrual period. In most cases, ovulation does not occur during menstruation.