Contraceptive injection

Pregnancy happens when sperm reaches an egg and fertlises it. The injection works in three ways to interrupt this process:

• It stops ovulation
• It thickens the mucus around the cervix, which makes it harder for sperm to get through
• It makes the lining of the womb thinner so that a fertilised egg cannot implant

The injection is a method long-acting reversible contraception (or LARC). These methods don’t rely on you remembering to take them, but they do need a trained doctor or nurse to administer or fit them for you.

The most commonly used injection is Depo-Provera (or DMPA). Depo-Provera and Noristerat must be administered by a doctor or nurse. However, there is now an injection called Sayana Press which you can be taught to inject yourself at home.

The injection is available free of charge from contraceptive clinics, your GP and Brook. Find your nearest using our find a service tool.

Contraception and sexual health services such as Brook are free and confidential, including for people under the age of 16. Health professionals work to strict guidelines and won’t tell anyone else about your visit unless they believe you’re at serious risk of immediate harm. Find out more about Brook’s confidentiality policy.

You will need to see a doctor or nurse to discuss which of the three injections is most suitable for you. Sayana Press (the one you inject yourself) is not available everywhere at the moment.

When you go to get the injection, an appointment will typically include:

• A few questions about your medical and family history, to work out what would suit you best.
• The doctor or nurse will take your blood pressure and they will weigh you.

Depending on the type, you will need to go back to the clinic either 8, 12 or 13 weeks for your next injection. If you are using the Sayana Press (which you inject yourself at home) you only have to go back to the clinic annually because you will be given a years supply.

You can have the injection at any time in your menstrual cycle if you are certain you are not pregnant. If you’re given the injection during the first five days of your period you will be protected against pregnancy immediately.

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. You may also be required to take a pregnancy test after the injection has been given.