WOMEN who use a revolutionary contraceptive patch are at a greater risk of blood clots and other serious side-effects because of the higher doses of hormones it delivers, its makers said yesterday.

The patch, which is called Evra and is worn on the skin like a plaster, was introduced in Britain in 2003 to claims that it could be the greatest family-planning breakthrough since the Pill.

It is used by many Britons, with more than 30,000 prescriptions given out in England last year. About four million women are thought to use it globally.

Ortho-McNeil, the manufacturer and a subsidiary of the pharmaceutical giant Johnson & Johnson, gave warning yesterday that women on the patch are exposed to about 60 per cent more oestrogen than those using typical birth-control pills.

However, the Family Planning Association (FPA) said that the small number of women in Britain who had starting using it should not suddenly stop the treatment and instead should discuss the options with their doctor.

The patch works in the same way as the combined oral contraceptive pill, delivering female hormones, progesterone and oestrogen, into the bloodstream. These stop the ripening and release of an egg from the ovary, and trick the body into thinking that ovulation has occurred. However, hormones from patches get into the bloodstream and are removed from the body differently than those from pills, resulting in higher exposure.

The patch has been welcomed as a major advance in contraception because it lasts a week, freeing women from the shackles of daily pill consumption. It also bypasses the stomach, removing the risk of nausea or vomiting making it less effective.

But yesterday Ortho-McNeil, which is based in the United States, confirmed that it was issuing an updated warning for the patch after meetings with the Food and Drug Administration. The alert comes after reports that patch users die and suffer blood clots at a rate three times higher than women taking the Pill. About a dozen women, most in their late teens and early 20s, died last year from blood clots believed to be related to the birth-control patch, and dozens more survived strokes and other clot-related problems.

However, in Britain only one case of a blood clot in the lungs and one of DVT have been reported since August 2002. Experts said that users did not need to panic as the risks remained small. They added that women should not stop using the patch without finding an alternative contraceptive, as the dangers of an unwanted pregnancy were much greater than those of the patch.

Several lawsuits have been filed in the US by families of women who died or suffered blood clots while using the patch, and lawyers say that more are planned.

Ortho-McNeil said that the patch remained a safe and effective birth-control option for many women when used according to the product’s label. It said that most side-effects were not serious and those that were occurred infrequently.

The company said that serious risks, which could be life-threatening, included blood clots, stroke and heart attacks, and increased if the woman smoked. Certain women should not use the patch, according to the product information, including those with blood clots, certain cancers and a history of heart attack or stroke.

Toni Belfield, the director of information at the FPA, said: “Any new information about how a method works, its advantages and disadvantages is useful as it enables women to make a more informed choice about their contraception.

“Women should not suddenly stop using the patch as they would risk pregnancy, but if concerned should seek advice from their health professional.”

According to the Associated Press, documents released to lawyers as a result of recent litigation show that Ortho- McNeil has been analysing the FDA’s death and injury reports, creating its own charts that document a higher rate of blood clots and deaths in association with the patch than with the Pill.

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