The first is a normal physiological situation, because as women age, the metabolic level of pigment in the body will change, which can lead to the accumulation of pigment down there, which over time can lead to the skin of the vulva is black; second, it may be caused by inflammation, such as women suffering from chronic endometritis, pelvic inflammatory disease, cervicitis, ovarian inflammatory disease and fallopian tube infection. When a woman has chronic gynecological inflammation, the inflammation can lead to an increase in the permeability of the mucous membrane of the skin and blood vessels, which can cause substances in the blood and inflammatory secretions to leak out onto the surface of the mucous membrane, causing the vulva to turn black. etc., which can indirectly or directly cause the vulva to become darker.