The most common symptom is an increase in vaginal discharge. Before ovulation, the discharge tends to be water-like, more abundant and thinner, due to the fact that the estrogen level in a woman’s body begins to rise, and estrogen can make the mucus of the cervix thin, which facilitates the entry of sperm into the uterine cavity to meet the egg and facilitate pregnancy. On the day of ovulation, most of the discharge becomes mucus-like, with a clear, drawn-out change, indicating that the woman is ovulating. After ovulation, some women may also experience pain in the belly and back pain, which is due to the small amount of follicular fluid that enters the woman’s pelvis while the egg is being discharged.