David’s Ovulation Test is used on the 10th day of menstruation and is tested once a day. The test paper is placed in the urine at a fixed time each day for testing, and if there is a red bar, it proves that the luteinizing hormone level in the urine is low. When the test shows one red bar dark and one red bar light, it means it is weakly positive. When the urine test shows two red bars, it is positive, which indicates that ovulation will occur within a short period of time and the woman has a high chance of getting pregnant during this period. If a woman’s menstrual cycle is irregular, it is best to combine it with the development of follicles under ultrasound, when the follicles are between 1.8-2.5 cm in diameter, it indicates that ovulation has arrived.