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Contraceptive injection

What is it?

The injection contains the hormone progestogen. It is a long-term method of contraception that lasts for 8-13 weeks depending on the type. The injection is administered in your buttocks, upper arm, abdomen or thigh, depending on the type.

This method does not protect you against sexually transmitted infections (STIs), so you may need to use a condom as well to help protect you against most STIs.

The contraceptive injection How does it work?

The contraceptive injection works by:

  • Stopping the ovaries releasing an egg
  • Thickening the mucus of the cervix to act as a barrier to sperm
  • Stopping a fertilised egg settling by keeping the lining of the womb thin

The contraceptive injection How effective is it?

The injection is over 99% effective when used correctly.

What are the benefits?

  • You do not have to remember to take a pill every day
  • You are protected against pregnancy for eight to 13 weeks (depending on type used)
  • Doesn't interrupt sex
  • May be suitable for breastfeeding women
  • Hormones do not have to go through the stomach so protection is not affected by sickness or diarrhoea

The contraceptive injectionWomen may not be able to/may not want to use it if they:

  • Don't want any changes to their periods
  • May want to get pregnant in the next year
  • Are at risk of developing osteoporosis

Women should not use it if they:

  • Are allergic to any of the ingredients of the injection
  • Might be pregnant
  • Have, or might have cancer of the breast or reproductive organs
  • Have active liver disease
  • Have unexplained vaginal bleeding

The contraceptive injection Possible side-effects?

As with all medicines side effects can occur but not all women will experience side-effects. Side effects may include:

  • Stomach pain
  • Feeling sick
  • Changes in appetite
  • Weight changes
  • Headaches
  • Changes to periods – lack of periods, heavy periods, bleeding between periods
  • Breast pain
  • Acne
  • Mood changes

The contraceptive injection What if......?

I miss my appointment for having my injection?

If you don’t have your injections at the times your doctor or nurse has advised you will need them, then you may no longer be protected against pregnancy. If you miss your appointment, contact your doctor or nurse as soon as possible.

I want to become pregnant?

Your periods and fertility may take a while to return to normal after you stop using the injection. Ideally you should wait for one period before trying to get pregnant. Waiting means the pregnancy can be dated more accurately, and you can seek some pre-pregnancy advice from your healthcare professional.

Remember: Contact your doctor or nurse if you have any concerns or are worried / unsure about anything to do with your contraception.

Have you decided which might be the right contraception for you? If not check out the other choices, if you have, jump to Step3: How do I change?

© 2015 Merck Sharp & Dohme Ltd. All rights reserved.

Job code: WOMN-1160817-0000

Date of preparation: September 2015

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