(1) Date projection method: In women with regular menstruation, the day of ovulation is on the 14th day before the next menstrual period, and the day of ovulation can be projected according to the menstrual cycle. (2) Basal body temperature measurement: If the body temperature curve is biphasic, the day with the lowest body temperature may be the day of ovulation. (3) Observation of changes in cervical mucus: In the middle of the menstrual cycle, the day when the leucorrhea is more and thinner, egg-white like, clear, transparent and long drawn, is likely to be the day of ovulation. Some people may have pink or light red leucorrhea, while others may have pain or a feeling of falling on one side of the lower abdomen. (4) Use a contraceptive eugenics test mirror: put a drop of saliva on the lens and dry it visually by air or bake it under a lamp. (5) Ovulation test paper: Luteinizing hormone (LH) peaks about 24 hours before ovulation, so the increase of LH concentration becomes an indicator for ovulation test. When the test strip is placed in the morning urine, the appearance of two indicator lines indicates that ovulation is likely to occur. Items (2) to (5) above are manifestations of hormonal cyclical changes. Even though there are typical manifestations, the eggs are not always ready to be ovulated. (6) Continuous ultrasound monitoring of follicles: The size of the follicles, their expulsion and the thickness of the endometrium can be monitored to guide the proper timing of intercourse.