Contraceptive injection

One contraceptive injection can protect you from pregnancy for between 8 and 12 weeks.

The contraceptive injection is an injection containing the hormone progestogen. There are two types of injectable contraceptive, Depo-Provera which lasts for 12 weeks and Noristerat which lasts for 8 weeks. Depo-Provera is more usually used in the UK.

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The contraceptive injection is one of the types of contraception called a LARC. LARC stands for 'Long Acting Reversible Contraception'. LARC methods don't rely on you remembering to take them, but they do need a professional (like a doctor or a nurse) to give them to you. They are very effective.

How does the injection work?
How do you use the injection?
What's good about the injection?
What do you have to watch out for with the injection?
How effective is the injection?
What makes the injection less effective?
Who can use the injection?

How does the injection work?

The hormone progestogen stops ovulation (release of an egg) and thickens the mucus around the cervix, which makes it difficult for sperm to get into the womb.

How do you use the injection?

The hormone is injected into a muscle,usually the bottom or the upper arm.

If you're given the injection during the first five days of your period you will be protected against pregnancy immediately.

It's okay to have a contraceptive injection at any time of the month, as long as there's no risk that you could already be pregnant.

If you have the injection on any other day of your cycle you will not be protected for the first seven days, so you will need to use another method of contraception, like condoms, for seven days.

What's good about the injection?

• Does not interrupt sex.
• Women do not have to remember to take a pill.
• May reduce heavy periods.
• Can make period pain or pre-menstrual tension less likely.
• The injection is not affected by vomiting or diarrhoea, or certain medication.

What do I have to watch out for with the injection?

• Does not protect against sexually transmitted infections (STIs).
• Periods may be irregular or stop.
• Can lead to some weight gain.
• Can cause slight thinning of the bones by reducing bone mineral density (usually recovers once the injections stop).
• Can take a year or more after stopping the injection for regular periods to return.

How effective is the injection?

Injectable contraception is over 99% effective. This means that less than 1 in every 100 women who use the injection will get pregnant each year.

What makes the injection less effective?

Follow-up injections must be given on time. If you miss just one injection, you are at risk of pregnancy.

Who can use the injection?

The contraceptive injection is suitable for most women. A doctor or nurse will ask about your own and your immediate family's medical history, weigh you and take your blood pressure, just to check it will be suitable for you.

Women who are under 18 years old may be able to use the contraceptive injection, but only after careful examination by a doctor because of its effect on bone density.