Pregnancy affects all organ systems in the body, including the skin. Some skin changes are physiological, whereas others such as the dermatoses of pregnancy are pathological. Dermatologists regularly encounter pregnant patients, and the identification of normal skin changes and their differentiation from disease states are essential to insure the well-being of both mother and fetus. This review discusses the physiological skin changes in pregnancy, including alterations in pigmentation, hair, nail, and connective tissue, as well as vascular and hematologic changes and modulation of glandular function.