The Pill Ups Chance of Stroke -- But Few Women at Risk
July 5, 2000 -- So does it or doesn't it? You've heard that the Pill increases your stroke risk, and then you've heard it doesn't. Now a new study says that although it appears to up women's risk -- even at low doses -- that few women of child-bearing age who are taking the Pill are at risk anyway.
A review of 40 years of research that explored the association between birth control pills and stroke has found a slightly increased risk for women using oral contraceptives (OC), even with the newer, low-estrogen varieties. However, to be on the safe side, George Hademenos, PhD, recommends women "stay with the low dosage."
The findings, which represent data on more than 120,000 women worldwide, were reported in a recent issue of the Journal of the American Medical Association.
"The bad news is that oral contraceptives are associated with increased risk of stroke," co-author of the study S. Claiborne Johnston, MD, MPH, tells WebMD. "But the good news is, for the vast majority of women it makes absolutely no difference whatsoever and should not influence the decision to use OCs." Johnston is with the department of neurology at the University of California, San Francisco.
Hademenos, who is a staff scientist with the American Stroke Association (ASA) in Dallas, agrees. "[This study] sheds light on the fact that we need to be aware that OCs are a risk factor for stroke, especially for women who are in a high-risk population," he tells WebMD. "Still, the risk is so slight, it's no cause for alarm." The ASA is a division of the American Heart Association.
Women considered to be in the high risk population are those with high cholesterol, high blood pressure, diabetes, a family history of stroke, and/or those who smoke.
However, what was surprising and a bit confusing about the data, Johnston admits, is that it seemed to show the stroke risk was the same in smokers and nonsmokers. Still, he cautions smokers are at increased risk "because smoking in itself increases the risk of stroke. It's a confusing message, but the main point for women is, stop smoking. If a woman makes the decision to do both those things [take OCs and smoke], she is putting herself at greater risk of stroke than if she were to do one of those things alone."
As a result of the findings, Johnston says some women "will be concerned because of a family history of stroke or other stroke [risk] factors." Now, with the help of their doctor, "they have more information to make an educated decision."
While birth control pill controversy is likely to continue, researchers outline stark consequences of not choosing to use oral contraceptives.
"If OC use were replaced by the second most popular birth control method, the male condom, an estimated 687,000 additional unintended pregnancies would result per year in the United States, with an associated 26 strokes and 33 deaths based on complication rates of pregnancy and abortion," they write. This is in contrast to the one additional stroke the researchers found for every 24,000 women using the low-estrogen birth control pills.
"In summary, while OC use is associated with increased stroke risk among current users, the absolute effect is small with current dosages," Johnston says, "this additional risk appears to be outweighed by the health benefits of OC use in improved birth control."
For more information from WebMD, visit our Diseases and Conditions Pregnancy and Stroke pages.