Detailed answer

During pregnancy, hormonal fluctuations, specifically increased levels of estrogen and progesterone, can stimulate the production of melanin in the skin. This can result in dark patches or spots, known as hyperpigmentation. The condition is commonly referred to as melasma or the 'mask of pregnancy'. It typically affects areas of the face, such as the forehead, cheeks, and upper lip. The exact cause of melasma is not fully understood, but hormonal changes play a significant role in triggering this condition. It is important to use sunscreen and take preventative measures against sun exposure during pregnancy to minimize the effects of hyperpigmentation.