By Nancy Deutsch
NEW YORK, Jul 05 (Reuters Health) - Women taking low-estrogen preparations
of birth control have more than twice the risk of ischemic stroke than women not
taking any form of oral contraceptive, new research shows.
Ischemic strokes occur when arterial disease blocks blood flow to part of
the brain, causing brain damage.
When the new low-estrogen preparations of birth control pills came on the
market, they were touted as being much safer than the higher-estrogen
preparations in existence--and they are, study author Dr. S. Claiborne Johnston
of the department of neurology at the University of California, San Francisco,
told Reuters Health. However, clinicians have considered them virtually
risk-free for ischemic stroke, and they are not, he said.
"I thought you were safe" on these preparations, Johnston admitted. "I do
believe the studies suggest it doubles your risk."
Still, while the risk is greater for women who take low-estrogen
combinations versus those not taking anything, the risk remains very, very
small, he said. "The bottom line is your perspective on this," he stated.
Johnston and colleagues conducted a meta-analysis of studies published on
the topic from January 1960 through November 1999.
Sixteen studies that investigated the risk of ischemic stroke and oral
contraceptive use were included in the meta-analysis published in the July 5th
issue of The Journal of the American Medical Association.
The researchers found that there are an additional 4.1 ischemic strokes per
100,000 nonsmoking women with normal blood pressure on low-estrogen oral
contraceptives, or 1 additional stroke per 24,000 such women in 1 year.
Women taking birth control pills with higher estrogen--those preparations
containing more than 50 micrograms of estrogen--had almost three times the risk
for ischemic stroke of women not taking anything.
Johnston said his team conducted the study to obtain more information that
would allow women to make informed, educated decisions as to whether they should
take low-estrogen birth control pills, he said. Despite these results, "I tell
my patients not to worry about it."
Birth control pills are far more effective than any other non-permanent form
of birth control presently available, the authors note.
If couples were to use condoms instead of the Pill, there would be an
estimated 687,000 additional unintended pregnancies per year in the United
States, and 33 deaths based on complications resulting from pregnancy and
abortion, the report indicates.
This is a not a lower death rate than that associated with oral
contraceptive use, but the economic and psychological impact of unintended
pregnancies is high, the researchers add. "My feeling is that the alternatives
are not good for contraceptives," Johnston told Reuters Health.
In terms of the prevention of unwanted pregnancies, and the relatively small
risk of stroke associated with the use of the Pill, "I think it's a good
trade-off. This is really quite a small risk to the average woman."
