Medical Health Encyclopedia

Oral contraceptives (OCs), commonly known collectively as "the Pill," contain combinations of an estrogen and a progestin (either a natural progesterone or the synthetic form called progestogen). They are most often used for treating endometriosis and are as effective for most women in treating pain from endometriosis as the more potent gonadotropin releasing hormone agonists. OCs may reduce the risk of ovarian cancer by 30% to 50% and of endometrial cancer by 50%, which is a potentially important benefit in women with endometriosis. (Patch contraceptives are available, but they may increase the risk for menstrual cramping.)

Click the icon to see an illustrated series detailing the birth control pill.

When used throughout a menstrual cycle, they suppress the actions of other reproductive hormones (luteinizing hormone, or LH, and follicle stimulating hormone, or FSH) and prevents ovulation. There are many brands available. The estrogen compound used in most oral contraceptives is estradiol. Many different progestins are used, and there are many brands. None to date have proven to be superior over others. Women should discuss the best options for their individual situations with their physician.

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Estrogen and progestin each cause different side effects. The most serious side effects are due to the estrogen in the combined pill. Uncommon but more dangerous complications of OCs include high blood pressure and deep-vein blood clots (thrombosis), which may contribute to heart attacks or strokes in rare cases. It should be noted that a long-term study of 46,000 British women found no difference in mortality rates between women who took OCs and those who did not. Studies have been conflicting about whether estrogen in oral contraception increases the chances for breast cancer, and if it does, which women are at risk. A reassuring 2002 study supported an earlier major study, with both finding no evidence that OC use increases the risk for breast cancer, even in women who have taken them for 15 years of more or had taken them at young ages. Still, more research is needed to verify these findings, given previous reports of a slightly higher risk.

Progestins