Some Birth Control Pills Increase Risk of Deadly Blood Clots
June 15, 2000 -- There's now a new reason to evaluate the risks and benefits before filling that prescription for birth control pills. The most modern birth control pills increase the risk of death from blood clots in the lung, according to a recent study published in the medical journal The Lancet from researchers in New Zealand. The risk is very small, but greater than previously realized, their study shows.
David Skegg, senior researcher of the study, tells WebMD that the risk of developing these clots in women taking the birth control pills was much higher than expected. He says their results may be high in this study because the newer birth control pills are used a great deal in New Zealand. Fewer women in the U.S. use these brands of birth control pills. Skegg is professor of preventive medicine at the University of Otago Medical School in Dunedin, New Zealand.
Since birth control pills were first introduced in the 1960s, they've been known to lead to a slightly increased risk of blood clots in the legs and lungs. A blood clot in the legs is often due to injury or inactivity. A person who has this condition may notice swelling and pain in his leg or thigh.
But sometimes a piece of the clot breaks off, travels through the body, and eventually blocks up one of the blood vessels in the lungs. At this point, the person may experience sudden shortness of breath, cough, faintness, or pain in the chest.
The condition is rare, and deaths due to such clots are few and far between -- only 1 or 2% of all cases. Although the association between birth control pills and these clots has been established, this study now shows a link with fatal bloodclots.
The research team looked at New Zealand's records on all cases of death from blood clots in the lungs in women of childbearing age, from 1990 to 1998. They found that two thirds of the women who died from the clots had taken birth control pills during their life. After analyzing their data, the researchers conclude birth control users were nearly 10 times more likely to develop deadly blood clots in the lungs than nonusers.