An American company has been given the go-head to market the first ever contraceptive patch.

The patch releases the same hormones as the contraceptive pill and is said to be 99% effective.

Some research has suggested that patches might be even more effective than the Pill - because women are less likely to forget to use one.

The patch would need to be changed once a week for three weeks. Then the woman wears no patch during her normal menstrual period before starting again.

It has been designed to stay on while bathing and swimming, and will be available on prescription in American next year.

The cost is expected to be approximately $40 a month.

Extensive testing

The approval by the US Food and Drug Administration (FDA), follows years of clinical trials.

Anne Weyman, chief executive of the Family Planning Association said she was sure the patch would be very popular if introduced in the UK.

That will not happen until the UK Medicines Control Agency (MCA) licences it for use here.

Dr Patricia Stephenson, one of the patch trial researchers, said: "Although there are a variety of birth control methods to choose from, many women still desire new options."

The patch may not be a good option for every woman, the FDA said.

Warning notes

Women who weigh more than approximately 14 stones (196 lbs) may not get a high enough contraceptive dose, it warned.

The patches should be applied to the lower abdomen, buttocks or upper body, at a different location each week.

It must never be placed on the breast, warned the FDA.

They carry the same risks and side-effects as the Pill, including nausea or breast tenderness, and a small risk of blood clots, heart attack and stroke, particularly if women smoke while using the contraceptive.

US researchers believe that a wholesale switch to patches might reduce pregnancy rates, although studies have shown no difference in pregnancy rates between the two methods.

Average compliance was 88.2% for women using patches compared with 77.7% for those taking the Pill.