About the contraceptive injection

Contraceptive injections contain a progestogen hormone, which is similar to that which occurs naturally in women. This stops a woman releasing an egg every month (ovulation) so that she doesn’t get pregnant.

These injections last for between 8 and 13 weeks, depending on the type you use. This means you do not have to remember to take or use contraception daily. The injection is known as a long-acting reversible method of contraception (LARC). Injections are estimated to be over 99% effective when women come in for their injections on time. However typical use is 94% effective. There is now an alternative injection which women can self-administer. Ask your sexual health clinic or GP for more details.

How it works

The contraceptive injection works in the same way as the implant. It steadily releases the hormone progestogen into your bloodstream. This is similar to the hormone that is naturally released by a woman during her period. A steady release of progestogen prevents the ovaries from releasing an egg each month (ovulation). They also make it harder for sperm to get into the womb and reach an egg.

How to use it

You just need to make sure you return for your next injection when it’s due. You will normally book the next injection every time you have one, so you can plan ahead.

It’s worth remembering that the contraceptive injection does not protect you from sexually transmitted infections (STIs). So we recommend always using a condom as well, as this is the best way to reduce your risk of STIs.

Who can use it

Most women can be given the contraceptive injection. However, you may not be able to use it if you:

  • Think you might be pregnant
  • Want to keep having regular periods
  • Want a baby in the next year – as it can take a while for your periods and fertility to return to normal
  • Are at risk for osteoporosis (thinning of the bones)
  • Have arterial disease (or a history of heart disease or stroke), liver disease, cirrhosis, liver tumours, breast cancer (or have had), and/or diabetes with complications


There are many advantages to using the contraceptive injection:

  • Convenient – you do not have to remember to take a pill every day (but do need to remember to have your injections)
  • Good for women who cannot use oestrogen-based contraception
  • Safe to use while breastfeeding
  • Not affected by other medicines
  • May reduce heavy, painful periods and help with premenstrual symptoms
  • May offer some protection against cancer of the womb


It’s also worth bearing in mind that, when it comes to using the contraceptive injection:

  • Periods may become more irregular, heavier, lighter or stop completely
  • Periods and fertility may take time to return after stopping the injection
  • The injection takes up to 12 weeks to leave the body so any side effects may continue for this time
  • You may put on weight, particularly if you are under 18 and are overweight with a body mass index of 30 or over
  • One type of injection (Depo-Provera) may affect your bones. This is more of a problem for women already at risk of osteoporosis
  • Other reported side effects include: headaches, acne, breast tenderness, changes in mood and loss of sex drive

Where to get it

Most types of contraception are free in the UK, and are available to all women and men through the NHS. Places where you can get contraception include:

  • Most GP surgeries – talk to your GP or practice nurse
  • Sexual health clinics like those run by Virgin Care, which offer both contraceptive and STI services. If you’d like to, you can book an appointment now
  • Community contraception clinics
  • Some genitourinary medicine (GUM) clinics
  • Some young people’s services, like those run by Brook

Need contraception?

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