Look at the faces of some women and you'll notice little brown blotches, especially on the forehead, cheeks and chin.  It's not dirt; they're spots of hyperpigmentated skin known to physicians as "melasma or chloasma."  They often appear during pregnancy, hence the name "mask of pregnancy."

Why pregnant women get these blotches may be related to hormones, since pregnancy is a time for profound hormonal change.  Supporting this theory is the fact that women taking birth control pills also commonly get melasma.  Remember, too, though, that other women and even an occasional normal man can get these dark splotches on the face.

The mask of pregnancy can last beyond pregnancy or the pill and can be a cosmetic liability, especially for women with darker skin types.  Naturally, the store shelves are stocked with skin bleaching agents, which can help, but may also, at times cause irritation or rashes.  If those dark patches don't respond to OTC remedies or disappear with time, the dermatologist can use prescription bleaching agents, light chemical peels, microdermabrasion or even pulsed light treatments to reduce the unwanted dark color.

Now, if you see little brown blotches on the otherwise radiant face of a woman you know it may not be dirt, just something equally down to earth.  For a copy of this script, access our web site, speakingofhealth.com.  Speaking of Health, I'm Dr. Steven Andrew Davis, for CBS News.