Last November the U.S. Food and Drug Administration warned that the Ortho Evra contraceptive patch by Ortho-McNeil Pharmaceutical, Inc., a J & J unit based in Raritan, N.J. might increase the risk of blood clots because it contains more estrogen than a typical-control pill. The company said it would conduct additional studies and Thursday released the first set of results.

One study that looked at a database of 200,000 women showed that risk of blood-clots among Ortho Evra users was about the same as the risk among women using a typical birth control pill. That study was published on the Web site of the journal Contraception. The study is also looking at heart attack and stroke risks, but that analysis is still ongoing. J & J said, “the currently available data do not show an increase in the risk of the combined endpoint of heart attack and stroke.”

The other study, which has not been published, is being conducted by a unit of Ingenix, which is unit of UnitedHealth Group (UNH), showed a two-fold increase in the risk of blood clots, or venous thromboembolic events, compared to women on a regular birth control pill. The same data does not show an increase in the risk of heart attacks and strokes, J & J said. The company said the data from both studies was still being analyzed.
The patch, which has been used by more than 5 million women since it was approved in 2002 is applied to the skin and is changed once a week. It contains estrogen and progestin, which is released into the blood stream and is designed to prevent pregnancy. The FDA has said women using the patch are exposed to about 60% more estrogen than if they were taking a typical birth control pill containing 35 micrograms of estrogen. The increased estrogen exposure from the patch could increase the risk of blood clots.
The FDA has scheduled a press briefing on Friday to discuss the birth-control patch.