The risk of blood clots in the legs and lungs may be higher for women using the birth-control patch instead of the pill, according to a warning on the product's label disclosed Wednesday.
The Food and Drug Administration said it updated the label on the Ortho Evra birth-control patch to reflect the results of one study that found women using the patch faced twice the risk of clots than did women on the pill. However, a second study found no difference in risk between the two forms of birth control.
"Even though the results of the two studies are conflicting, the results of the second epidemiology study support FDA's concerns regarding the potential for Ortho Evra use to increase the risk of blood clots in some women," the FDA said in a notice published on its Web site.
Initial results of the two studies were made public in February by the patch's manufacturer, Ortho Women's Health & Urology. The Raritan, N.J.-based company is owned by Johnson & Johnson.
Last year an investigation by The Associated Press, citing federal death and injury reports, found higher rates of blood clots in women using the patch.
The FDA recommended that women with concerns about clots and use of the patch talk to their doctors.
In November, the FDA updated the label on Ortho Evra to alert women that using the patch exposes them to about 60 percent more estrogen than using birth-control pills.
Johnson & Johnson previously has said clots remains rare and that they have been reported as a potential risk of all hormonal contraceptives.
Ortho Women's Health & Urology said in a statement that data will continue to be collected for both studies. The company also said it would continue to provide new information to the FDA.
The company reported in filings made last month that Ortho Evra sales have declined significantly following the previous label revision and a spate of media coverage of the clot issue. Since the patch went on sale in 2002, more than 4 million women have used it.
The company also disclosed that approximately 500 people have filed lawsuits or made claims related to injuries they allegedly suffered from the Ortho Evra patch.
The investigation by The Associated Press found that patch users die and suffer blood clots at a rate three times higher than women taking the pill. About a dozen women died in 2004 from blood clots believed linked to use of the patch, the AP reported. Dozens more suffered strokes and other clot-linked problems.