Patch May Be Riskier Than Birth Control Pill

The easy-to-use birth control patch has become popular with millions of women in recent years, an alternative to the pill and other forms of birth control.

Now, those women are being warned that delivering hormones by skin patch may be riskier than taking the pill. A new study says patch users are at increased risk of blood clots compared with women using oral contraceptives.

Dr. Daniel Shames of the Food and Drug Administration said Friday that the new findings did not require immediate government action, but he urged women to discuss the risk with their physicians.

One new study found users of the Ortho Evra patch had twice the risk of clots compared with women taking birth control pills. A second analysis found no difference in risk.

“For some people the patch may be better because some people don’t reliably take the pill, or don’t want to take the pill or forget the pill,” Shames said.

“On the other hand, we need to interpret what these results mean,” he said. “But these results are preliminary, so we can’t make hard comments about it.”

The results of the two studies were made public Thursday by the patch’s manufacturer, Ortho Women’s Health & Urology. The Raritan, N.J.-based company is owned by Johnson & Johnson.

Although one study found no increased risk of clots, the interim results from the other suggested that the risk of venous thromboembolic events -- clots in the legs and lungs -- doubled for patch users, Ortho said.

Because the confidence intervals of oral and patch results overlap, there actually may be no increased risk from the patch, or it may be more than double, said Shames, the FDA’s director for reproductive and urologic drug products.

He said the risk of a nonfatal blood clot is about one per year in 10,000 women not using a contraceptive. For those using a hormonal contraceptive such as the patch or pill, the risk rises to three to five, he said.

“These are fairly unusual events,” said Shames. He noted that in preapproval testing of the patch on about 3,000 women, there were two reports of blood clots, but one involved a woman who had undergone surgery. Surgery increases clot risk.

The studies also are looking at the risk of heart attacks and strokes among users of the two types of contraception. No difference has been detected, but the numbers are small and it will take 18 more months to see whether a disparity emerges, Shames said.

Clots are a potential risk of all hormonal contraceptives. The patch exposes users to about 60% more estrogen than the pill does, notes a label on the patch that was added in November.

Since the patch went on sale in 2002, more than 4 million women have used it.

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Associated Press writer Andrew Bridges contributed to this report from St. Louis.