Birth control packages traditionally supply hormone pills for 21 days and placebo pills for seven, bringing a period once a month. But in 2003, the FDA approved Seasonale, a new kind of birth control that enabled women to have full periods only four times a year. In 2007, the FDA approved Lybrel, the first oral contraceptive designed to stop a woman's period indefinitely. With these drugs on the market, women now have more choices when it comes to when -- or if -- they have a monthly cycle.