Stretch marks will slowly disappear after delivery. After pregnancy, the level of estrogen, progesterone and chorionic gonadotropin will increase, endocrine changes will occur, the metabolism of pregnant women will be high, sebum and sweat glands will be hyper-secreted, and chloasma and stretch marks will appear. The stretch mark is usually a black line from the abdomen to the pubic bone, and the color of the nipples and areolas of pregnant women will also become darker, which is related to the hormonal changes in the body of pregnant women after pregnancy. After delivery, the hormone level in the body of pregnant women will drop significantly, so the stretch marks, melasma and hyperpigmentation will gradually fade or disappear after delivery. It is recommended to avoid strong UV direct irradiation and outdoor activities as much as possible, which can reduce the pigmentation situation.