How can a woman know if she is ovulating?

Patient's question:

Menstruation did not arrive as expected

Doctor's answer:

Vaginal discharge increases: Before ovulation, a woman's vaginal discharge is small in amount, viscous, and opaque. As ovulation approaches, the vaginal discharge gradually increases, becoming thin and milky white. During ovulation, the discharge amount significantly increases and becomes watery, transparent, and clear. The woman may feel damp and slippery in her vagina, and when wiping with toilet paper, there will be egg white-like stringy mucus. This increased vaginal discharge in women generally lasts for 2-3 days, which is the time when women are most fertile.