While it's not easy to prevent stretch marks, there are effective ways of removing them, or at least greatly minimizing them, after the fact -- especially if you're willing to go under the knife.
Surgery isn't necessary if what you're looking for is simply an improvement, as opposed to a cure. The least invasive approach is the topical-application route. Exfoliating products like tretinoin (Retin-A) and glycolic acid, which remove the top layer of skin cells to stimulate fresh skin formation, can reduce the severity of the scars. Less invasive means less effective, though. It's not going to work miracles.
For more significant results than topical treatments but still without the cutting, laser removal is an option. A dermatologist or cosmetic surgeon uses laser light to essentially burn off the scarred skin so new, unmarred skin will grow in its place. This will definitely reduce the appearance of the marks, and it's less traumatic than surgery, so it has a much shorter recovery time. However, it's also not a miracle worker.
For a cosmetic miracle -- or the closest you can get to such a thing -- you'll probably have to endure the scalpel. In what's basically a tummy tuck procedure, a cosmetic surgeon removes the scarred belly skin below the navel, basically folding the tummy. It literally gets rid of the stretch marks (and the pregnancy "pooch" along with it). The procedure has downsides, though. It's very invasive, so it requires a long, uncomfortable recovery period -- not ideal for a new mom with a demanding infant. It's also very expensive, thousands-of-dollars expensive. And since it's cosmetic surgery, it's not covered by insurance.
Laser therapy is less costly, but still not covered. Topical products are the least costly option.
Ultimately, unless the marks are particularly severe or you have a low tolerance for imperfection, you may prefer to save your money and wait it out. Stretch marks fade significantly over time. Within a year or less, they'll go from screaming red to pearly white, with a slightly depressed appearance, usually a shade or two lighter than your natural skin tone. They'll still be there, but you probably won't notice them much unless you go looking. And there's not much time to go looking when you're running around after a toddler.
For more information on stretch marks, pregnancy and related topics, look over the links on the next page.