The birth control pill is one of the most intensely researched medications in history. Since its development more than fifty years ago, it has been used by millions of women worldwide.
The early pill formulations raised concerns about blood clots, heart attack, and stroke, spurring exhaustive research on oral contraceptives beginning in the 1960s and 70s. Since then, new formulations of the Pill with low-dose hormones have been introduced, and today’s pills contain about one-eighth to one-tenth of the estrogen in early pills. Research shows that today’s birth control pills are safe for most women, and that healthy, nonsmoking women have little if any greater risk of heart attack or stroke than women who do not use the Pill.
Any woman of any age has a tripling of her risk of blood clots while on the Pill, although this risk is still quite small overall. To put the risk in perspective, the risk of a blood clot during pregnancy is double the risk of getting a blood clot while on the Pill. Women with some cardiovascular conditions or some chronic illnesses and women over age thirty-five who smoke should not take the Pill. In rare cases, women who use birth control pills may develop liver tumors. Some evidence suggests that oral contraceptive use slightly increases the risk of getting cervical cancer or breast cancer among women under thirty-five, but these associations are controversial and have not been fully established.
Long-term use of the Pill provides significant noncontraceptive health benefits. Long-term use protects against ovarian and endometrial (uterine) cancers, and research suggests that these protective effects may last up to fifteen years or more after stopping the Pill. Women who take the Pill have lighter, shorter periods (thus reducing the risk of anemia), are less likely to develop ovarian cysts, and have a decreased incidence of pelvic inflammatory disease (PID).
Though the information above is based on research on the Pill only, it is reasonable to infer that the same cautions and side effects apply to all methods that contain both estrogen and progestin, such as the patch and the ring.