What happened to the black vulva?

Female vulva black, mainly after puberty, ovary began to show ovulation, periodic secretion of estrogen and progesterone, estrogen will make the vulva skin, mucosa show coloring phenomenon, so the skin, mucosa will be darker than normal skin color, this is a normal phenomenon, you can not give special treatment, as long as keep vulva clean, and pay attention to sexual life and menstrual hygiene. During menstruation, it is best to use cotton sanitary napkins. After pregnancy, the estrogen in the body increases thousands of times, and the skin color of the vulva will deepen. This is also a normal physiological phenomenon. And after pregnancy, nipples and areola will also show color deepening.