Blood clot warning to go on Ortho Evra birth control patch

The U.S. Food and Drug Administration (FDA) says early results of a new study show that women who use the Ortho Evra contraceptive patch are twice as likely to develop blood clots than others who took a birth control pill.

Ortho Evra is a weekly prescription patch that releases ethinyl estradiol (an estrogen hormone) and norelgestromin (a progestin hormone) through the skin into the blood stream.

The FDA advises women to talk to their doctor or healthcare provider about whether the patch is the right method of birth control for them.

The FDA says women taking or considering using the product should work with their health care providers to balance the potential risks related to increased estrogen exposure against the risk of pregnancy if they do not follow the daily regimen associated with typical birth control pills.

Because Ortho Evra is a patch that is changed once a week, it decreases the chance associated with typical birth control pills that a woman might miss one or more daily doses.

The FDA says more research and further evaluation are needed to gain a better understanding of the risk of blood clots.

Dr. Daniel Shames, director of the FDA's division of reproductive and urologic drug products, says updated labeling has been approved for the product to warn healthcare providers and patients that women who use it are exposed to to higher levels of estrogen than most birth control pills.

Ortho Evra was the first skin patch approved for birth control.

Shames says that these results are preliminary and further evaluation is necessary to understand what the results mean.

The new warning is a direct result of the FDA and the manufacturer Johnson & Johnson, comparing the levels for estrogen and progestin hormones in users of Ortho Evra with those in a typical birth control pill.

Increased estrogen exposure is thought to increase the risk of blood clots and the new warning specifically states that women who use Ortho Evra are exposed to about 60 percent more total estrogen in their blood than if they were taking a typical birth control pill containing 35 micrograms of estrogen.

The FDA says it will continue to monitor safety reports for the Ortho Evra patch and says the manufacturer is conducting additional studies.