The pregnancy hormones affect the elastic tissue in the skin, and pink, red or purplish streaks often appear as the skin stretches. These are called stretch marks and often appear on the belly, breasts and thighs. Stretch marks fade after birth and become a silvery-gray, but they don’t usually disappear completely. You may also get more pigmentation in your skin during pregnancy and get brown patches on your face and body. You increase the risk of brown patches when you expose your skin to the sun, so be careful and take steps to protect you from the sun.
Source: - Lärobok för barnmorskor. Faxelid, E. Course literature 2001. - Myles Textbook for Midwives. Fraser, D. och Cooper, M. Churchill Livingstone 2003.