In about 70 percent of pregnant women, the pregnancy hormones cause an increase in the amount of melanin their skin produces. It leads to skin darkening.For most women, this discoloration disappears completely within a few months of giving birth, but there are ways you can minimize the discoloration while you?re pregnant and speed its disappearance.You can try sun screen lotions to protect from sun.Look for formulations that include titanium dioxide or zinc oxide, which are more effective sunblocks, to help prevent the UV rays from interacting with your skin. Orange pulp can help lighten the skin.Or try a milk mask ? mix together equal parts whole milk, almond oil, honey, and lime juice, and leave it on your skin for a half an hour. A deficiency of folic acid vitamin can cause the overproduction of melanin that comes with melasma. So take those prenatal vitamins, and supplement with folate-rich foods like dark green vegetables, beans, strawberries, and eggs. Make your own scrub with sugar and olive oil, or try lotions that contain alpha hydroxy acid and use it to exfoliate the skin.Try lightening creams that contain hydroquinone,azelaic acid cream etc,but i would recommend their use only after delivery.Most of the hyperpigmentations fade away after a few months of delivery..