Recent studies suggest that estrogens exert their effect in the skin Abstract Melasma represents the most common pigmentary disorder occurring in pregnancy. It mainly consists in a hyperpigmentation of the face and neck, due to an alteration of melanocytes' density and of melanin's concentration. At first sight it may appear to be a minor clinical condition, without vital risk, but clinicians consider it as an important cosmetic stigma difficult to treat and that may cause great emotional suffering. Jou rn a l o f Pi gmentar y D is o rd ers