The first step is to try to lighten the melasma spots at home. Start by exfoliating regularly (try an at-home microdermabrasion system, such as Neutrogena Microdermabrasion System ($20) followed by a cream or serum that contains Kojic acid. Kojic acid is derived from a mushroom that comes from Japan and its properties help to inhibit melanin (the hormone in your body that darkens skin color).
If you still need help with melasma, ask your doctor for a prescription hydroquinone cream. This ingredient helps to lighten the skin, but needs to be applied precisely. If you apply it to areas that do not need to be lightened, your skin can end up blotchy and worse than before!
The next step would be to ask your doctor about a professional grade peel, such as the VII Peel or Cosmelan. Cosmelan contains a mix of ingredients that also inhibit melanin production while lightening and brightening the skin. It does not contain TCA, so you can do it any time of the year.
Obviously, melasma can get worse in the sun, so it is best to choose an SPF of 50 or higher. Ideally look for a product that has zinc as well, which creates a physical barrier to the skin; many of the new zinc formulas come in a "clear" version, so you won't look like you have a white mask on your face.
Moms with melasma need to become master camouflage artists! Today there are great concealers and foundations that can hide these spots, but not feel super heavy. Mineral makeup is excellent because it contains a natural SPF. One to try is Bare Escentuals Original SPF 15 Foundation ($26). Dermablend is also known for its high converage concealers. For busy moms, try their QuickFix Concealer ($22).