Blood clot risks higher for patch users

Ortho Evra patch carries 60 percent more estrogen and is more likely to cause leg and lung blood clots than pills.

Overview

Some research suggests that the risk of leg and lung blood clots may be higher for women who use the birth-control patch instead of the pill. The Food and Drug Administration said it updated the label on the Ortho Evra birth-control patch in January 2008 to reflect the results of one study that found women using the patch faced twice the risk of clots, compared with women on the pill. But a second study found no difference in risk between the two forms of birth control.

Questions and answers

How does the patch work?

Dr. Sanjay Gupta, CNN chief medical correspondent: The birth control is the Ortho Evra contraceptive patch. Women wear a new patch on their bodies every week, for three weeks. They stop for a week and then apply a new one. It's simple, quick, and you don't have to think about it every day, like with birth control pills. The problem is, the Food and Drug Administration continues to warn women that the patch carries 60 percent more estrogen than the average birth control pill, and it's more likely to cause serious blood clots, compared with other contraception.

When did the FDA start taking action?

Gupta: In September 2006, the FDA updated the patch's label to let women know that using the patch exposes them to more estrogen, 60 percent more than birth control pills. Then in March 2007, the FDA looked at two studies funded by the maker of the patch, Johnson and Johnson, and noted that one study found that women who used the patch had no more risk of developing blood clots than women taking the average dose of birth control pills. But a second study -- and this is the one that alarmed them -- found that the Ortho Evra patch caused twice as many blood clots in women using the patch, compared with those taking birth control pills. So it's these studies, in particular the second one, that have caused the FDA to update the warning label on the patch.

So what can women look for on the label?

Gupta: The label, which has a warning section, shows the results of the studies, along with graphs that display the differences in birth control methods. It's a little complicated, but the FDA thinks women will be able to make a decision on their birth control method by using this information.

Why not just take it off the market?

Gupta: That's an extreme that the FDA really doesn't like to do. According to Johnson and Johnson, since the patch went on sale in 2002, more than 4 million women have used it. It's very popular, and the number of cases of blood clots, although not officially documented, is small.

The FDA says even if it doubled for those on the patch, perhaps just six women out of 10,000 would develop clots in any given year. But there is enough evidence out there for the FDA to at least warn women that there is this danger. Furthermore, this type of birth control doesn't protect a woman from pregnancy any better than birth control pills. Doctors say the main reason women use the patch is for convenience. They don't have to remember to take a daily pill. But the FDA believes a woman needs to weigh the pros and cons and talk to her doctor to see whether the convenience is worth the potential risk.

Are some women more at risk than others?

Gupta: Yes: women who smoke, and those who are obese. Smoking is huge, because it seems to contribute to the whole blood clot and stroke problem. In all birth control methods, if you combine smoking with taking estrogen, it raises the chances of developing these clots, which can kill women. Doctors don't know exactly why it happens, but they know it does happen. They recommend that women who smoke really think before they take any hormonal birth control, especially one that is as high in estrogen as the patch.

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