CR's Take:
		Women who use the patch because they have trouble remembering to take the pill should ask their doctor whether the higher risk of blood clots outweighs the risk of an unwanted pregnancy from missing doses of the pill. Women with a greater-than-average risk of blood clots--including those who have high blood pressure, smoke, and are older than 35--shouldn't use any contraceptive that contains estrogen.

A study that first prompted the Food and Drug Administration to issue a warning to users of the Ortho Evra patch last year has shown that the contraceptive does increase the risk of blood clots more than commonly used birth-control pills.

Researchers reviewed insurance claims data from some 340,000 women and found that patch users developed clots more than twice as often as women who took birth-control pills. However, the overall risk of developing clots from either method was still relatively small.

The study appears in the February 2007 issue of Obstetrics and Gynecology.

Since its launch in 2002 Ortho Evra has become a popular contraceptive choice because of its ease of use. The patch, which can be applied to the buttocks, arm, abdomen or torso, needs to be changed only once a week. It works by delivering pregnancy-preventing hormones through the skin directly into the blood stream. Studies have suggested that it has a 10 percent higher compliance rate than the pill.

But the patch also exposes women to 60 percent more estrogen than oral contraceptives over a 21-day period, and heightened levels of the hormone can increase the risk of clots and other side effects. In 2005 a warning about the increased estrogen exposure was added to the patch's label, following an analysis by the FDA and Ortho Evra's manufacturer.

The FDA reviewed unpublished data from this study last year. And though the findings were at odds with earlier research that did not find an increased risk of blood clots among patch users, the agency was concerned enough to update Ortho Evra's label to include the information.

Our consultants consider the study to be a reminder that consumers must carefully weigh risks and benefits in choosing contraceptives. The pill, with its longer track record, may be a more prudent choice. Evidence also suggests that the patch may not be as effective in women who weigh 200 pounds or more.

Women who choose the patch because they have trouble remembering to take the pill should ask their doctor if the possible risks of extra estrogen outweigh the risk of an unwanted pregnancy from failing to take the pill consistently. Women with a greater-than-average risk of blood clots--including those who have high blood pressure, smoke, and are older than 35--shouldn't use any type of contraceptive that contains estrogen.