If the ovulation test paper detects ovulation, if it does not detect a strong positive, it is most likely due to the following reasons: 1. There is no ovulation at all, so it does not detect a strong positive. When the luteinizing hormone reaches its peak, that is, about 24-48 hours after a strong positive, ovulation will occur. If you can’t get a strong positive result, it is likely that you are not ovulating at all, so it is recommended that you use ultrasound to understand whether you are ovulating or not. 2. The wrong method of detection, such as drinking too much water before retaining urine, is diluting the luteinizing hormone in urine, so you can’t detect a strong positive result. In this case, it is recommended not to drink too much water two hours before urine retention. It is also recommended to test daily from the 12th day of menstruation until the 20th day of menstruation.