Ovulation monitoring test strips are used to monitor the release of LH in the mid-menstrual period. A strong positive ovulation test normally lasts 48-50 hours. The principle of using ovulation test strips to measure ovulation is to measure the level of luteinizing hormone in the patient’s body, and ovulation occurs when luteinizing hormone increases to a peak of secretion. Usually, 1-2 days before the arrival of ovulation, the secretion of luteinizing hormone changes from weak to strong, and the ovulation test paper shows a weak positive to a strong positive, which may last 48-50 hours in most women. After the onset of ovulation, the luteinizing hormone in the body decreases and the ovulation test paper changes from a strong positive to a weak positive, at which time intercourse should be arranged and the chance of conception is higher within 24 hours. In addition, body temperature can also be monitored clinically. The basal body temperature can increase by 0.2-0.5℃ after ovulation to determine whether ovulation has occurred.