The study is the latest effort to determine the risk of cardiovascular disease associated with the three generations of oral contraceptives. The first generation, introduced in the 1960s, had relatively high doses of two hormones, estrogens and progestogens. The doses were reduced in the second generation of oral contraceptives to reduce the risk of heart attacks, strokes and venous thrombosis, the potentially fatal blockage of a vein. The third and latest generation uses lower doses of newer progestogens.
Based on a study of several hundred women who used all three generations of oral contraceptives and had suffered heart attacks, researchers led by Dr. Frits M. Rosendaal, an epidemiologist at Leiden University Medical Center, in the Netherlands, found a slightly reduced risk of heart attacks for the third-generation drugs. However, the study found no reduced risk of venous thrombosis (blood clots in veins), which is a bigger killer than heart attacks for younger women. Findings appear in the Dec. 20 issue of The New England Journal of Medicine."If we combine all this, the preference in young women and starters should remain with the second-generation pills," Rosendaal says. "For older women, say over 30, there may be a small benefit of using third-generation oral contraceptives, but it seems to me that much more can be gained by being cautious in prescribing any oral contraceptive to women over 35, and take into account risk factors such as smoking and hypertension."
Smoking is the one risk factor whose effect is overwhelming for any woman, whether she takes an oral contraceptive or not, says Lisa Chasan-Taber, professor of epidemiology at the University of Massachusetts and co-author of an accompanying editorial.
"The risk of myocardial infarction [heart attack] due to cigarette smoking is substantially higher than for any oral contraceptive," she says. "As for switching from a second generation to a third generation oral contraceptive, the overall risk is low. A woman should consult her individual physician about which oral contraceptive to use."
Rosendaal and his colleagues share the view about the dangers of smoking. Doctors should remember that "the most important advice they can give these women remains to quit smoking," they write. But Rosendaal says the third-generation pill is not as safe as many women believe.
"This study confirms that oral contraceptives increase the risk of heart attacks, as we have known since the 1960s," he says. "What is new is that it also shows that this risk has not gone away with the lowering of the estrogen dose, as the manufacturers tried to make us believe."
When women consider using an oral contraceptive, Rosendaal says, "They should know that if they have risk factors for heart disease [family history, smoking, hypertension, diabetes], the risk of heart attacks is much higher. They should know that all these risks increase with age, and that especially oral contraceptive use in a woman who has one of these risk factors is not a good idea. They should know that oral contraceptives with lower estrogen dose, which are often promoted as safer, aren't."
What To Do
The American Heart Association tells women that "if you don't smoke, and you don't have high blood pressure or other cardiovascular disease, a low-dose oral contraceptive may be recommended for you. If you want to use the pill -- or are already using it -- don't smoke. This is good advice whatever your age."
You can learn about oral contraceptives and your heart from the American Heart Association. Meanwhile, the American Medical Association's Contraception Information Center has more general information.