Women with normal menstrual cycles usually ovulate once a month, and the ovulation time is regular. Under the influence of sex hormones, only one primordial follicle matures each month, and the mature egg is then discharged from the ovary, through the fallopian tube, into the abdominal cavity and uterus. Sexual intercourse on the day of ovulation is most likely to result in pregnancy. The possibility of conception also exists in the days before and after the day of ovulation, and this period, which forms together with the day of ovulation, is called the ovulation period. Outside of the ovulation period, conception does not occur. Ovulation is usually detected by the following seven methods: 1) Basal body temperature method, which indicates ovulation when the temperature is consistently high; 2) Ultrasound follicle monitoring method, which is a series of ultrasound waves that track the growth and discharge (disappearance) of eggs, and can measure the size of the follicle and the thickness of the endometrium in infertile patients and guide the appropriate time for intercourse. The advantage of this method is that it is more accurate, but it takes some time; 3. Hormone measurement, such as luteinizing hormone test, luteinizing hormone (LH for short) reaches its peak about 24 hours before ovulation, and the increase in LH concentration becomes the best indicator to test ovulation. 7.Use Eve instrument: put the oral secretion into a small cup every month for testing, through the computer processing of the instrument, ovulation day can be analyzed; 8.Use contraceptive eugenics test mirror: when testing, use the tip of the tongue to put a drop of saliva on the slide, air dry or bake under the lamp to visually inspect, test once a day, if the typical “lamb’s tooth structure” appears, it means ovulation. If a typical “lamb’s tooth structure” appears, it indicates ovulation and can be used at home to identify the figure. A combination of these methods can be more reliable. However, in general life, for the convenience of examination and detection, ovulation is often projected based only on the external manifestations (signs) of ovulation. The most commonly used methods are: 1. Calendar method: to calculate the ovulation period according to the menstrual cycle; 2. Basal body temperature measurement method: to calculate the ovulation period according to the change of body temperature related to ovulation, if the temperature curve is biphasic, then the day before the rise of body temperature is the ovulation day. 3. Cervical mucus observation method: Women’s menstrual cycle is divided into dry period – wet period – dry period. In the middle of the menstrual period, when the leucorrhea appears more and abnormally thin, it is the wet period, and the day when the observed discharge is egg-white like, clear, transparent, highly elastic and long-drawn, it is likely to be the ovulation period. Each of these 3 methods has its own advantages and disadvantages: the calendar method can be used to project the ovulation period and the safe period before and after ovulation. However, it is only applicable to women with normal menstruation, and sometimes ovulation is advanced or delayed due to environmental changes and emotional changes, so it is not accurate enough; the basal body temperature measurement method can determine the date of ovulation and the post-ovulatory safety period, but cannot determine the pre-ovulatory safety period in advance, which is more troublesome and requires strict requirements, and if the temperature is not measured according to the regulations, the date of ovulation cannot be accurately determined; the cervical mucus observation method can determine the ovulation period and the pre-ovulatory and post-ovulatory safety periods The cervical mucus observation method can determine ovulation and the safe period before and after ovulation with a high degree of correctness, but the user must be trained and fully mastered before using it. If these three methods are used in combination, they can be more effective and avoid the shortcomings.