Women who test with ovulation test paper before menstruation sometimes have a positive test, the chances are low. The reasons why ovulation test paper appears positive before menstruation: First, it may be due to the delay in ovulation of the ovaries, ovulation occurs just before menstruation, so ovulation test paper will appear positive changes. Second, it may be that the woman’s test method is inaccurate or the reagent fails to detect the wrong situation, there will also be a positive. In most cases, women with normal menstrual cycles will ovulate in the middle of their menstrual cycles, and the test paper will be positive. If there is no error in the test method or reagent, the ovulation test will be negative before the onset of menstruation, proving that the luteinizing hormone in the woman’s body is relatively low, and menstruation will occur in a shorter period of time.