How reliable is it?
With careful use, less than one woman in 100 will get pregnant in a year. With less careful use, three or more women in 100 will get pregnant in a year.
How it works
It contains two hormones - oestrogen and progestogen - which stop a woman releasing an egg each month (ovulation).
Does not interrupt sex
Often reduces bleeding, period pain and pre-menstrual tension
Protects against cancer of the ovary and womb and some pelvic infections
Suitable for healthy non-smokers up to the menopause
May not be suitable for some women. A full medical history should be taken.
May be temporary minor side effects.
Not suitable for heavy smokers, smokers over 35 or for women who are breastfeeding.
Does not protect against sexually transmitted infections.
Not reliable if taken over 12 hours late or after vomiting or severe diarrhoea, unless an extra method is used.
Some drugs may stop the pill working - a doctor or pharmacist will advise.
Pill users should try not to smoke.