Why it happens is not known, but it does appear hormone-related. It’s harmless, but some people dislike it.
The darkening itself is melanin, the same pigment protein that gives you a tan. That’s why sunlight can make melasma patches look worse – the tan around these melanin-free patches darkens.
The usual counsel is to stay out of the sun, to start keeping track of cosmetics and cleansers that may be irritating your skin, and to consider, after pregnancy, local treatment with Retin-A, hydroquinone, or corticosteroids. Your doctor may also ask you to consider a different form of birth control. There isn’t much else to do, and treatment does not guarantee a response.
The mask of pregnancy, as melasma is sometimes called, very often goes away. Or most of it goes away. Or it goes away and comes back with the next pregnancy, or with changes in contraception. If it comes back, it may last for several years, or it may be with you for life.
Questions about your skin? Ask our dermatologists online for $35.