If ovulation is not detected by the test paper during ovulation, it may be due to the following reasons: 1. The time of the test is not right, it is recommended to start testing with ovulation test paper on the 12th day of menstruation. 2. The urine is left at the wrong time, unlike the test for early pregnancy, the urine for ovulation is left around 10 am for examination in order to know whether the luteinizing hormone in the urine has reached its peak. If ovulation is not found through the test, it may be due to contamination of the ovulation test paper, resulting in a negative result. 3, there is really no ovulation, so the test through the ovulation test paper is a negative result, you can continue to monitor with ovulation test paper for a month, you can also monitor ovulation through ultrasound.