Skin Darkening in Pregnancy

Darkening of the skin in pregnancy is called hyperpigmentation and it used to be that we thought it was related to what is called melanocyte-stimulating hormone (MSH), now we've decided it really is not certain why pregnant women get this skin darkening. Virtually 90% of patients will exhibit darkening of their skin during pregnancy, even if it's only in selected areas or only slightly darker. In fact extra pigment containing cells, known as melanocytes seem to cluster in areas, and can even form knots. These new skin knots that you can see are due to new skin melanocytes. If a woman gets darkening of her face it's called chloasma. This darkening is best treated after the pregnancy with some form of skin lightening and most commonly in the past we used tretinoin ointment. Other areas of the body that may darken are the areolae around the nipples, the inner thighs, or the linea alba which is a fine line that runs down the center of the abdomen. About half of all women will have chloasma itself. Moles, or nevi, while they may darken along with the overall darkening of the skin, should not change in size in pregnancy and if they do you need this evaluated.