Darkening of the nipples in pregnancy is associated with changes in hormone levels, which can be restored, but not during pregnancy and only after delivery.
Darkening of the nipples after pregnancy is associated with increased levels of estrogen and progesterone. Estrogen and progesterone can stimulate the development of milk ducts and alveoli, leading to an increase in breast size, and can also color and enlarge the nipples.
Because estrogen and progesterone levels are high throughout pregnancy, the darkening of the nipples lasts throughout the week of pregnancy. After delivery, nipple color can gradually return due to the rapid decline in estrogen and progesterone.
Nipple darkening is a physiological manifestation of pregnancy and does not require special treatment, but usual attention to breast care, such as regular wiping of the breasts, avoiding extrusion of the nipple, and choosing loose and comfortable underwear, and so on.