Combined oral contraception - the pill

The combined contraceptive pill is a tablet that contains artificial versions of the two female hormones, oestrogen and progestogen. You need to take the pill at around the same time each day.

It is:

  • Over 99% effective when you use the method correctly every time 
  • Over 91% effective when you don’t always use the method correctly

How does it work?

The combined pill releases the artificial form of the hormones - oestrogen and progesterone - which are absorbed into your body. 

It works by:

  • stopping ovulation (an egg being released from your ovaries)
  • thickening the mucus at the neck of the womb (uterus) so it is difficult for sperm to enter the womb 
  • thinning the lining of the womb and this prevents a fertilised egg from settling (implanting) in the womb

It is important that you talk to a doctor who will assess what contraceptive option is best for you.


  • It does not interrupt sex.
  • Often reduces bleeding and period pain, and may help with premenstrual symptoms.


  • If you miss a pill, or are vomiting or have severe diarrhoea, it can be less effective.
  • It is not suitable if you smoke and are over 35 years of age.
  • It is not suitable if you are obese.
  • It may not be suitable if you are breastfeeding. Check with your doctor.
  • Its effectiveness may be reduced by taking certain medications.
  • Does not protect against sexually transmitted infections