This medicine is a type of hormonal contraceptive commonly known as the 'mini pill' or progestogen-only pill (POP). It contains the active ingredient desogestrel, which is a synthetic progestogen, similar to the natural progestogens produced by the body.

Desogestrel is thought to act as a contraceptive primarily by preventing the release of an egg from the ovary (ovulation). It also acts by increasing the thickness of the natural mucus at the neck of the womb, making it more difficult for sperm to cross from the vagina into the womb. By preventing sperm entering the womb, successful fertilisation of any eggs that are released is less likely.

Desogestrel also acts to change the quality of the womb lining (endometrium). This prevents the successful implantation of any fertilised eggs onto the wall of the womb, thereby preventing pregnancy.

The progesterone-only pill should be taken continuously every day, unlike combined pills, which are usually taken every day for three weeks, followed by a pill-free week. This progesterone-only pill should be taken continuously at the same time every day for it to be effective at preventing pregnancy. If you are more than 12 hours late in taking your pill you will not be protected from pregnancy and should use an extra barrier method of contraception, eg condoms, for the next seven days, while continuing with your normal pill taking.