The darkening of the armpits of pregnancy is related to increased melanin secretion and skin pigmentation after pregnancy. Hormonal changes in the pregnant woman’s body after pregnancy, increased secretion of melanocyte-stimulating hormone during pregnancy, while a large amount of estrogen and progesterone also have a melanocyte-stimulating effect, which will increase melanin. Melanin deposition in the armpit, it will lead to armpit skin black. The increase of melanin will cause the pregnant woman’s areola, nipple, abdominal white line, inguinal skin fold area, etc. may have hyperpigmentation, appearing skin darkening. The color usually lightens after delivery and the pigmentation disappears over time. This darkening is a normal reaction to pregnancy and is not a cause for much concern.