Women of reproductive age usually release an egg about once a month. The ovary gets an egg from the inside of the ovary to its surface by creating a blister or fluid-filled space around the developing egg. When the blister (or cyst) reaches the surface of the ovary, it bursts and releases the egg into the abdominal cavity. After this occurs, the blister can develop into another type of cyst, which makes a hormone (progesterone) that helps the pregnancy to grow. Most of these cysts come and go without problems. Sometimes, however, the cysts get large or painful; others may remain for months. Several decades ago, health care providers learned that women taking birth control pills had fewer cysts, since the pills usually kept an egg from being released. Based on this fact, many clinicians started treating these cysts with birth control pills to make them go away faster.
We did a computer search for all randomized controlled trials that studied use of birth control pills to treat these benign (also called functional) cysts. We wrote to researchers to find other trials. We found eight trials from four countries; they included 686 women. Three trials included women receiving drugs to help them get pregnant. The other five included women who developed cysts without fertility treatment. In none of these trials did oral contraceptives help the cysts go away faster. Thus, birth control pills should not be used for this purpose. A better approach is waiting two or three months for the cysts to go away on their own.