There are three main reasons for the itching symptoms after menstruation: 1. The wearing of sanitary napkins during menstruation causes the vulva to be stuffy, humid and less breathable, so there are symptoms of irritation of the local mucous membrane of the vulvar skin. 2. The normal vaginal pH value is weakly acidic, but when the menstrual blood flows through the vagina, it gradually destroys the weak acidity and makes the vagina appear alkaline. When menstrual blood flows through the vagina, it gradually destroys the weak acidity and makes the vagina appear alkaline. In this case, the beneficial bacteria and lactobacilli in the vagina will gradually decrease or even disappear, and the beneficial bacteria will change and the vaginal environment will become abnormal, which will lead to some discomfort. 3. The most important thing is vaginal itching, change in discharge and even odor. Therefore, when itching occurs after menstruation, it is important to find the cause and take targeted treatment.