The levels of estradiol from the patch are about 60 percent higher than in women taking the typical oral contraceptive pill, she says.

NPR: FDA Orders Label For Contraceptive Patch

With current oral contraceptive regimens, women take the pill for 21 consecutive days and have 13 periods a year.

CNN: Emerging contraceptive options

Dr Amy Berrington, of Cancer Research UK, said the link between oral contraceptive use and cancer risk was highly complex, with studies showing that taking the Pill reduced ovarian and endometrial cancer risk, but increased the risk of breast cancer risk and probably also cervical cancer.

BBC: Oestrogen in the Pill could offer protective benefits