The darkening of underarms after pregnancy is mainly related to hyperpigmentation caused by changes in hormone levels. After pregnancy, due to the increase of estrogen and progesterone levels in the body, which will lead to increased hyperpigmentation, resulting in certain parts of the color obviously darkened, such as nipples, areolas, armpits, abdominal white line, vulva and other parts of the body, there will be obvious aggravation of the phenomenon of hyperpigmentation, which belongs to the normal physiological phenomenon. Generally, after the hormone level returns to normal after delivery, the hyperpigmentation phenomenon will gradually reduce and subside. After pregnancy underarm black generally do not need special treatment, it is recommended that pregnant women usually eat more vegetables and fruits rich in vitamin C, pay attention to underarm hygiene, most of the postnatal period will gradually subside, such as underarm black symptoms can not subside for a long time after giving birth to the hospital to choose the laser to get rid of.