If you weren't taking a prenatal vitamin before getting pregnant, it is likely the first change you will make after discovering you are expecting. Flip through a baby magazine or browse the aisle at your local drugstore and you will find a number of vitamins on the market, all with various claims. While some doctors recommend patients take prescription vitamins, many over-the-counter versions feature similar ingredients.

Simple: Over-the-counter prenatal vitamins, like Nature Made Prenatal Multivitamins ($11 for 90), are preservative-free and high in a mama-to-be's necessary nutrients like folic acid, iron, and zinc.

Swank: Prescription prenatal vitamins, like Duet DHA ($43 for 60), contain higher doses of key vitamins, such as folic acid, iron, and calcium, as well as a separate pill containing omega-3 fatty acids. The extra dosage is believed to help mamas-to-be produce new red blood cells faster.