During pregnancy hyperpigmented spots can be quite common, especially on the face. It is a mechanism that involves major hormonal changes that occur in women in this particular period of their life. In fact, combining this with sun exposure, these spots are more likely to occur, even in younger subjects. In some cases their distribution can be so broad that they are called "pregnancy mask."
After childbirth and breastfeeding this glaring imperfection tends to disappear. It is important to know that there is the possibility to intervene if hormone restructuring does not solve the problem. You can try K5® Lipogel, a product designed to remove spots and lighten hyperpigmentation of the skin.