Combined oral contraceptive pill - COC

What is it?

  • A daily pill taken by mouth containing the hormones oestrogen and progesterone.

How does it work?

  • One pill is taken every day for three weeks out of four. The fourth week is a pill free week within which you normally get a period.
  • The hormones stop ovulation (eggs being released from the ovaries), thicken the mucus at the entrance to the womb preventing sperm getting through and thin the lining of your womb preventing implantation of a fertilised egg.

What’s great about it?

  • Very Effective. If taken perfectly the pill is >99% effective - less than one in 100 women will get pregnant each year. However pill users often don’t take it correctly (e.g miss pills) and such typical use means more women will fall pregnant (8 in 100).
  • Its effect on fertility is rapidly reversible.
  • Periods will usually become more regular, lighter and less painful.
  • Pre-menstrual tension and acne may improve.
  • Can protect against pelvic infection, ectopic pregnancy, fibroids and ovarian cysts.
  • May reduce the risk of cancer of the ovary, uterus and colon.

What’s not so great about it?

  • No protection against sexually transmitted infections (STIs) - condoms advised.
  • It is easy to forget to take the pills every day. If you forget to do so it may stop working.
  • Small increased risk of heart or stroke disease, blood clots in the legs/lungs, breast cancer and cervical cancer.
  • Can cause temporary side-effects such as headaches, mood change, breast tenderness and bleeding in between periods. These may wear off with time or by switching to a different pill.
  • Needs a regular prescription from a health care provider.
  • Its effectiveness can be reduced if you vomit or have diarrhoea.
  • Women with some medical conditions or taking certain medication are not advised to use it e.g. very overweight; smokers aged 35 or older.

Where can I get it?

  • Click here to text for an appointment at Chelsea and Westminster Sexual Health service.
  • Family planning clinics, some GPs and other sexual health clinics.

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