* Risk is especially low in younger women
* Pregnancy still carries much higher heart risks
By Gene Emery
NEW YORK, June 13 (Reuters Health) – The largest study yet
to examine the risks of hormone-based birth control has
concluded the contraceptives carry a small risk of stroke and
heart attack, depending on the method and type of hormone used.
But the risk for individual women remains extremely low,
particularly in younger women, a team of Danish researchers
reported on We dnesday.
Their findings, published in the New England Journal of
Medicine, suggest a higher risk of stroke in particular for
women using vaginal rings, and possibly hormonal skin patches —
though the second finding was based on a smaller group of women
and could have been due to chance.
Other factors — such as the belief that a patch or a ring
might be safer for women thought to be at risk of stroke — may
explain the higher rate of stroke in that group, said Dr. James
Simon, a women’s health researcher at George Washington
University in Washington, D.C., who was not involved in the
study.
Simon said the findings probably should not change how
doctors prescribe birth control, noting that the risks seen in
the study pale in comparison with the risks of stroke, heart
attack or death faced by women who get pregnant.
“None of the hormonal contraceptives studied were
associated with an excess risk of stroke that was unacceptable,
considering their contraceptive and noncontraceptive benefits,”
Dr. Diana Petitti of Arizona State University in Tucson wrote in
an editorial accompanying the study.
Previous attempts to assess the risk of stroke or heart
attack linked with hormonal contraceptives have produced
conflicting results.
In the latest study, a team led by Dr. Ojvind Lidegaard from
Copenhagen University Hospital analyzed the records of 1.7
million Danish women aged 15 to 49 to assess the potential
dangers associated with their contraceptive use. None of the
women had a history of heart disease or cancer.
They were followed for 15 years beginning in 1995.
Overall, the risk to individual women was small. One in
every 4,700 women had a stroke each year and one in every 9,900
suffered a heart attack.
Women taking contraceptive pills with a combination of
estrogen and progestin tended to have a higher risk of stroke
and heart attack than those not using hormonal contraception.
For some hormone combinations, that difference could have
been due to chance, but women using estrogen with norethindrone
or desogesterel at certain doses, for example, had double the
risk of both complications compared with non-users.
Still, Simon said the new research “shows very little
difference between the different pills for the same dose of
estrogen, which will make women’s choices larger.”
CONSIDER AGE
Neither the skin implant nor the intrauterine device (IUD)
containing only progestin was tied to an increased risk of
stroke or heart attack, though the number of women using those
methods was sometimes small.
Danish women using a vaginal ring had about a 2.5 higher
chance of stroke than those not using hormonal contraception.
For contraceptive patches, there was a trend toward more
strokes, but the researchers could not be confident the finding
was accurate.
Lidegaard said in an interview that many women have used
patches and rings “believing that these non-oral products could
confer less risk. But this is definitely not the case.”
He said age is a key factor when considering risks.
“If you are 20 years old and you double your risk of
(stroke), then you still have a very low risk because the
absolute risk is so low,” he said.
“On the other hand, if you are in the other path of
reproductive age, especially in the 40s, you should consider not
increasing your risk … further because it’s already increased
due to your age.”
Among all women, once they stopped using hormonal
contraception, their risk of strokes and heart attacks dropped
to the same level as the risk for women who had never used them.
Simon said women who think the findings mean they should
stop taking contraceptives are getting the wrong message,
because the risks associated with pregnancy are so much greater.
SOURCE: http://bit.ly/Knoxtc New England Journal of Medicine,
online June 13, 2012
(Editing by Genevra Pittman, Julie Steenhuysen and Dan Grebler)
