The process by which the oocyte is expelled along with its surrounding granulosa cells of the oocyte mound is called ovulation. If the menstrual cycle is normal, ovulation mostly occurs about 14 days before the next menstrual period. After the egg is expelled from the ovary, it can survive in the fallopian tube for 1-2 days to wait for fertilization. Normally, ovulation lasts for 10 days, which includes the 5 days before as well as the 4 days after the day of ovulation, in addition to the day of ovulation. However, if the menstrual cycle is longer, e.g. around 35 days, ovulation will take place on approximately 21 days. Because it varies greatly among individuals and can be influenced by many factors, a woman’s ovulation period may be irregular and can be determined by ultrasound monitoring of eggs, temperature measurement, cervical mucus testing, ovulation test strips, etc. During ovulation, women may show an increase in body temperature, which can be 0.3℃-0.5℃. Some women may show a small amount of bleeding or even pain during ovulation. The leukorrhea during ovulation is more watery, thinner, transparent, and stretched, and can be stretched up to about 10cm. Ovulation is also known as the danger period, when sexual intercourse is very easy to fertilize pregnancy, so if the couple is not currently ready to have children, should do a good job of contraception to avoid abortion after pregnancy, bringing harm to women.