Birth Control Patch May Up Clot Risk
Finding Is Preliminary and Needs More Study, Experts Caution
Feb. 17, 2006 -- Women using the Ortho Evra birth control patch may be twice
as likely to develop blood clots as women using birth control pills, say
That's according to preliminary data from a new study. But the study is
still being analyzed, and it's too early to be sure of the findings, experts
Another study on the same topic didn't show patch users to be at higher risk
of nonfatal clots than women using birth control pills. Ortho Women's Health
& Urology, which makes the Ortho Evra patch, announced both studies'
findings in a news release.
"We believe that these study results are important to make public so
physicians have additional information to consider in making personalized
decisions with their patients," Julie Keenan, spokeswoman for Ortho Women's
Health & Urology, tells WebMD.
Doctors already knew hormonal contraceptives -- not just the patch -- boost
the risk of clotting. The question is whether the patch carries a higher risk
than other hormonal contraceptives.
The facts on that aren't final yet. Meanwhile, women using or considering
the patch should talk to their doctors about their clotting risk, experts
About the Studies
The studies were based on information from two large databases of medical
insurance claims. Funding for both studies came from Johnson & Johnson,
which owns Ortho Women's Health & Urology, a division of Ortho-McNeil
So far, only one of the studies has been published. That study showed patch
users were at similar risk of nonfatal blood clots as women taking oral
contraceptives containing 35 micrograms of estrogen.
The interim report of the second study shows patch users at approximately
twice the risk of blood clots as women using oral contraceptives. That study's
analysis isn't finished, so its meaning isn't clear yet. The study "will be
published at a later date," states Ortho's news release.
Women using or considering the patch should talk to their doctors, the FDA's
Daniel Shames, MD, FACS, told reporters in a teleconference. Shames directs the
FDA's Division of Reproductive and Urologic Drug Products.
The studies included tens of thousands of women, says Shames. He didn't have
exact figures for the clotting events seen in those studies; Keenan couldn't
provide WebMD with those numbers, either.
The results are "preliminary" and need "further evaluation,"
says Shames. He notes that the researchers are checking to see if the patch
users in the studies were more likely to be smokers or obese, compared with
women taking birth control pills. That information might be available in May,
'Fairly Unusual Events'
All hormonal contraceptives carry some degree of clotting risk, Shames says.
He calls blood clots "fairly unusual events."
The FDA currently isn't seeking any changes in the patch's labeling, Shames
says. He adds that last November, the patch's labeling was updated to note that
its total estrogen exposure is about 60% higher than with oral