The term “great aunt” generally refers to menstruation. Menstruation is always a few days early can be through the cervical mucus observation method, basal body temperature measurement method and ovulation test paper to calculate the ovulation period. 1. Cervical mucus observation method: cervical mucus in the ovulation period will become thinner under the effect of estrogen, similar to egg white, and the degree of traction is particularly good, which is conducive to the passage of sperm and the combination of sperm and egg, this is the change of cervical mucus in the ovulation period. 2. Basal body temperature measurement: the body temperature measured before the body wakes up after a long sleep is the basal body temperature. Under normal circumstances, if the body temperature suddenly rises by 0.3℃-0.5℃ on a certain day of the menstrual cycle, it is a sign of ovulation, and the basal body temperature is the lowest in the 24 hours before ovulation. 3. Ovulation test paper: women with irregular menstruation can also apply ovulation test paper, according to the change of the color of the test paper to predict the ovulation period. If the interval between early menstruation increases, then you should go to the hospital in time and follow the doctor’s instructions to avoid delaying the consultation.