The Contraceptive Injection

zoe miller medical editor

Medically reviewed by

Dr Zoe Miller

Last reviewed: 03 Sept 2025

The contraceptive injection is a long-acting type of contraception that stops you from getting pregnant by releasing progesterone into your bloodstream. One type of injection, Dep-Provera, was licensed in the UK as a second-line contraceptive in 1984, before being approved as a first-line method in 1995. Sayana Press, a self-injectable progesterone-only contraceptive, was approved in 2015.

A single syringe on a pink background

Since its approval, the contraceptive injection has become a popular method, with 15% of UK women opting for this choice of birth control.

In this guide, we explore how the injection works, who can use it, the common side effects, and the pros and cons, which have helped to make it the 5th most popular birth control method in the UK.

We do not currently prescribe contraceptive injections, but you can explore our range of contraceptive pills instead:

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How does the contraceptive injection work?

The contraceptive injection contains a synthetic version of the hormone progesterone, most commonly medroxyprogesterone, which works to prevent pregnancy by:

  • stopping your ovaries from releasing an egg each month (ovulation)
  • thickening the cervical mucus, making it difficult for sperm to reach an egg
  • thinning the lining of the womb so that a fertilised egg is unable to implant and grow

How effective is the contraceptive injection?

When used correctly, the contraceptive injection is more than 99% effective at stopping pregnancy from happening. However, when typical use is considered, such as not getting your next injection on time, it’s closer to being 94% effective.

Types of contraceptive injection

There are 3 types of contraceptive injection available in the UK. They are:

Depo-Provera

Depo-Provera is the most popular contraceptive injection in the UK and contains the active ingredient medroxyprogesterone. It lasts for 12 weeks, but it can be injected within 12 weeks and 5 days from your previous injection and remain effective. It must be injected by a healthcare professional, usually in your buttocks.

Sayana Press

Sayana Press also lasts for 13 weeks, but is less popular than Depo-Provera. It also contains medroxyprogesterone and is usually injected in your lower abdomen or the front of your thigh. After a doctor or nurse has shown you how, you can inject Sayana Press yourself at home.

Noristerat

Noristerat is a contraceptive injection that is effective for up to 8 weeks and contains a different type of progesterone called norethisterone. It’s usually used for short periods rather than as a long-term contraceptive solution, such as when your partner is waiting for a vasectomy. A doctor or nurse must give this injection.

How long does the contraceptive injection last?

The contraceptive injection lasts for 8 to 13 weeks, depending on the type you are given:

  • the most common type, Depo-Provera lasts 12 weeks
  • the self-injectable Sayana Press lasts for 13 weeks
  • Noristerat offers protection for 8 weeks

For Depo-Provera and Sayana Press, you’ll usually need to book your next injection every 12 to 13 weeks to stay protected. Your doctor or nurse will let you know how often you will need to have it and when you should book your next one.

Side effects of the contraceptive injection

The medroxyprogesterone contraceptive injection can cause side effects in some people. The most common side effects, affecting more than 1 in 100 people, are:

  • headaches
  • stomach pain
  • bloating
  • feeling sick
  • nervousness or feeling depressed
  • changes to your periods
  • weight changes
  • reduced sex drive
  • dizziness
  • breast tenderness
  • back pain
  • feeling weak or tired
  • itchy skin
  • acne
  • hair loss
  • fluid retention
  • vaginal discharge changes

This is not an exhaustive list of side effects. You can check the potential side effects, including uncommon and rare ones, in the patient leaflet for your injection.

Are there any long-term risks to using contraceptive injections?

Yes, if you use medroxyprogesterone contraceptive injections for a long time (Depo-Provera and Sayana Press), there’s a chance that your bones will weaken and become more fragile, a condition known as osteoporosis.

There are things you can do to help prevent osteoporosis, such as:

  • exercising regularly
  • eating a healthy, balanced diet
  • making sure you get enough calcium in your diet (milk, cheese, and leafy green vegetables)
  • taking a vitamin D supplement or getting sunlight exposure

If you have the contraceptive injection for longer than 3 years, there is a slight chance of developing a rare type of brain tumour called a meningioma.

Who can use the contraceptive injection?

Most people who have started their periods can have the contraceptive injection. However, you must tell your doctor if you:

  • are pregnant, trying to get pregnant, or breastfeeding
  • have ever had an allergic reaction to medroxyprogesterone
  • have a condition called porphyria
  • have had breast cancer or any other cancer that is affected by hormones
  • have or have had liver problems
  • have had a blood clot in a vein, lung, or any other organ
  • have had a type of brain tumour called a meningioma
  • have high blood pressure

You should also tell your doctor if you have or have had any of the following health conditions:

  • angina or a heart attack
  • epilepsy
  • migraines
  • diabetes
  • hearing loss
  • asthma
  • lupus
  • gallstones
  • mental health problems
  • osteoporosis

Pros and cons of the contraceptive injection

There are pros and cons for all medications, including contraceptives. Here are some of the pros and cons of contraceptive injections:

Pros

✓ highly effective – over 99% effective when used correctly

✓ low maintenance – no need to remember a daily pill or weekly patch

✓ long-lasting – one injection lasts for 8 or 13 weeks

✓ contains no oestrogen – ideal for anyone unable to use combined hormonal contraceptives

✓ does not interfere with sex – no need to think about contraception every time you have sex

✓ may improve your period symptoms – most people find their periods become lighter or stop completely over time

✓ discreet – no visible devices or routines

Cons

✗ irregular bleeding – spotting or irregular bleeding is a common side effect in the first few months

✗ potential side effects – common side effects include headaches, weight changes, and mood changes

✗ delayed return to fertility – it can take up to a year for your fertility to return after you stop the contraceptive injection

✗ requires appointments – for the injection to give you continued protection, you’ll need to make appointments for repeat injections or to collect at-home injections

✗ no STI protection – you will need to use condoms to protect yourself against sexually transmitted diseases

Contraceptive injections vs other hormonal contraceptives

Active ingredient(s) Effectiveness (perfect use) How often you take it Common side effects
Injection Medroxyprogesterone or norethisterone Over 99% Every 8 to 13 weeks
  • headaches
  • mood changes
  • weight changes
    		•
    Combined pill Synthetic oestrogen and progesterone Over 99% Every day for 21 days, then a 7-day pill-free break
  • headaches
  • feeling sick
  • breast tenderness
  • mood changes
    		•
    Mini pill Synthetic progesterone Over 99% Every day
  • period changes
  • breast tenderness
  • mood swings
    		•
    Implant Synthetic progesterone Over 99% Every 3 years
  • changes to your periods
  • sore breasts
  • acne
  • headaches
    		•
    Patch Synthetic oestrogen and progesterone Over 99% Weekly for 3 weeks, followed by a week's break
  • skin irritation
  • breast tenderness
  • headaches
  • feeling sick
  • mood changes
    		•

    Where to get the contraceptive injection in the UK

    You can get the contraceptive injection for free on the NHS at:

    • some GP surgeries
    • sexual health clinics, also known as family planning or contraception clinics
    • some young people’s services

    You can find your local contraception service if you live in England using the NHS ‘Find contraception services’ tool. Alternatively, you can contact your GP surgery for more advice.

    FAQs

    Can I get pregnant right after stopping?

    Yes, although it can take up to 1 year for your fertility to return to normal after stopping the contraceptive injection, it is possible to get pregnant right after stopping the contraceptive injection. Although some people may conceive within a few months, it can take up to 1 year for your periods and ovulation to become regular after you stop the contraceptive injection.

    Can I inject myself at home?

    Yes, you can inject yourself at home if you are given Sayana Press, a particular type of contraceptive injection. A doctor or nurse will show you how to do this before you inject it yourself. If you are given Depo-Provera or Noristerat, this will need to be given by a healthcare professional.

    What happens if I miss my next dose?

    If you do not have the contraception injection within the given time frame for that injection, you can get pregnant. If you forget to have your injection, speak to your doctor or nurse as soon as you remember. If you’ve had unprotected sex, you may need to take a pregnancy test before your next injection.

    Do you get your period on the injection?

    It is possible to not have periods or experience changes to your period while using the contraceptive injection. Many people who use the contraceptive injection get lighter, shorter, or irregular periods, or their periods may stop altogether.

    Sources

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