Hormone Combo in Contraception Boosts Heart Risk
Women who use birth control products that contain a combination of estrogen and progestin may double their risk for heart attack and stroke.
In a large-scale Danish study of 1.6 million women of childbearing age, researchers found that women who took birth control pills that contained both estrogen and progestin were 1.5 to two times more likely to have a heart attack or stroke than women who didn't use these oral contraceptives.
The risk grew to 2.5 to three times for women who used vaginal rings and transdermal patches that contained this combination of hormones.
But the researchers were quick to note that the risk was tied to age.
"A doubled risk for thrombotic stroke is not very serious when you are 20 years old, because your risk at baseline is very low," says lead author Oivind Lidegaard, at Rigshospitalet, a state-run hospital in Copenhagen. "On the other hand, when you are 35 years old or older, the risk is no longer that low, and you should be more careful with choosing those products with the lowest risk of thrombotic complications."
Earlier this year, the FDA said that birth control pills that contained drospirenone, a synthetic version of the hormone progesterone, would need new labels warning of the higher risk for blood clots.
That change was aimed at blood clots in veins. The Danish study focuses on the risk for clots in arteries, which can cause heart attacks and stroke.
The Danish study found significantly higher rates of heart attack and stroke among women with diabetes and high blood pressure and among those older than age 35. The relative odds of suffering a heart attack doubled among women 40 to 44, compared with those who were 35 to 39.
Kathleen Hoeger, M.D., at the University of Rochester in New York, says that birth control pills are beneficial even if they have risks. "I wouldn't want a study like this ... to tell us these are dangerous drugs," Dr. Hoeger says. "The drugs have risks, and those risks are really well-defined. This data gives doctors a lot of confidence to be able to offer advice."
The study was published in a recent issue of the New England Journal of Medicine.
Always talk with your health care provider to find out more information.