Combined pill

How effective is it?

Over 99 per cent effective if taken according to instructions.  Less than one woman in 100 will get pregnant in a year.

How does it work?

Contains two hormones – oestrogen and progestogen. It stops ovulation, thickens cervical mucus to prevent sperm reaching an egg and thins the lining of the uterus to prevent a fertilised egg implanting.


What are the advantages?

  • Often makes periods regular, lighter and less painful.
  • Reduces risks of cancer of the ovary, uterus and colon.
  • Suitable for healthy non-smokers up to the age 50.
  • When you stop using the combined pill your fertility will return to normal.

What are the disadvantages?

  • Not suitable for very overweight women or smokers over 35 years.
  • Low risk of serious side-effects such as blood clots, breast and cervical cancer.
  • Can be temporary side-effects such as headaches, nausea, mood changes and breast tenderness.

Anything else I should know?

  • Missing pills, vomiting or severe, long-lasting diarrhoea can make it less effective.
  • Some medicines can make it less effective.
  • Breakthrough bleeding and spotting is common in the first few months.