Johnson & Johnson’s once-weekly birth control patch Ortho Evra (norelgestromin/ethinyl estradiol transdermal system) has had new labelling slapped on it after findings showed women were receiving a much higher dose of oestrogen that those taking a contraceptive pill.

The new warning states that women are likely to be exposed to about 60% more oestrogen in using the contraceptive patch that through using a typical birth control pill, which in turn may raise the risk of side effects. Although in information on its site Ortho McNeil stresses “it is not known if there are differences in the risk of serious side effects based on the differences between Ortho Evra and a birth control pill containing 35 micrograms of oestrogen,” other observers have suggested that the product can lead to an increased risk of blood clots.

An Associated Press investigation of more than 16,000 adverse event reports made by Ortho Evra users to the US Food and Drug Administration found it had been linked to a dozen deaths last year amongst young women. Dozens more, it claimed, had suffered strokes or other medical problems related to blood clots.

Ortho Evra was first approved in 2001 – becoming the only contraceptive patch on the market [[21/11/01h]].