The choices Contraceptive injection

Contraceptive injection

What is it?

The injection contains the hormone progestogen only. It is a long-term method of contraception that lasts for eight or 12 weeks depending on the type. The injection is administered in your upper arm, leg or buttocks.

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

How effective is it?

The injection is over 99% effective.

What are the benefits?

• You do not have to remember to take a pill every day
• You are protected against pregnancy for up to eight or 12 weeks (depending on type used)
• Doesn't interrupt sex
• Suitable for breastfeeding women
• Ideal if taking estrogen is not an option
• It may reduce heavy periods and premenstrual symptoms
• Hormones do not have to go through the stomach so protection is not affected by sickness or diarrhoea
• It provides some protection against cancer of the womb

Who may not be able to / may not want to use it?

Women who:

• Don't want any changes to their periods
• Have breast cancer or have had it in the last five years
• Have had a heart attack or stroke
• Have a blood clot in a vein or artery
• Are at risk of developing osteoporosis
• Have unexplained bleeding from the vagina
• Have active liver or gall bladder disease
• Don't have time to make regular appointments to renew the injections
• Might be pregnant
• Want to get pregnant in the next year
• Have diabetes with complications or who have had diabetes for more than 20 years

Possible side-effects?

Not all women will experience side-effects. Once the injection has been given it cannot be removed from your body so if you have any side effects they may continue for some time afterwards.

• Your fertility and periods can take a while to get back to normal after stopping some contraceptive injections
• Can increase the chance of spots, headaches, tender breasts and changes in mood and sex drive
• Periods may change and irregular bleeding may continue for some months after stopping the injection
• Weight gain

What if

I miss my appointment for having my injection?

You should make an appointment to see your doctor to have your injection as soon as you remember. It is important to have your injection at the right time to protect against pregnancy.

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 start pre-pregnancy care, such as taking folic acid and stopping smoking.

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

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