Progestogen only pill - POP

What is it?

  • A daily pill taken by mouth containing the hormone progesterone.

How does it work?

  • One pill is taken every day.
  • The hormone thickens the mucus at the entrance to the womb preventing sperm getting through and thins the lining of your womb preventing implantation of a fertilised egg. Some POPs also stop ovulation (eggs being released from the ovaries).

What’s great about it?

  • Very Effective. If taken perfectly it is >99% effective - less than one in 100 women will get pregnant each year. If it is not taken perfectly more women may fall pregnant.
  • Periods may stop or become lighter or less frequent.
  • Its effect on fertility is rapidly reversible.
  • Can be used by women who cannot take oestrogen (COC/Patch/ring) e.g. overweight women.

What’s not so great about it?

  • No protection against sexually transmitted infections (STIs) - condoms advised.
  • It needs to be taken at the same time each day otherwise it may stop working. It can be difficult remembering to take the pill on time.
  • Periods may stop, be irregular, prolonged or more frequent. This may settle with time.
  • Can cause side-effects such as spotty skin, breast tenderness or weight change but these should settle within a few months.
  • Some women get ovarian cysts.
  • Needs a regular prescription from a health care provider.
  • Its effectiveness can be reduced if you vomit or have diarrhoea.
  • Some medications can stop it working.

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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