The contraceptive injection – Everything you need to know

Maddie Braidwood - The Lowdown
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Reviewed by Dr Becky Mawson on Dec 2, 2021

If you're done with having to remember to take the pill every day and also cringe at the thought of the coil, then this convenient contraceptive could be the answer!

TLDR… what’s the lowdown?

  • The contraceptive injection is a progestogen-only method of contraception that comes in three types: The Depo-Provera, the Sayana Press and the Noristerat
  • It can take between several months to over a year for your fertility to return to normal after stopping the injection
  • The injection is the only method of contraception where weight gain is a proven potential side effect
  • The contraceptive injection can impact your periods, causing them to be heavier, lighter, shorter or irregular. The majority of women experience no periods altogether.
  •  You can now buy the Sayana Press injection directly from The Lowdown.
  • This post contains affiliate links we have vetted and receive a small commission from.

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The contraceptive injection is a little different from all the other contraceptives. This contraceptive does not need to be inserted into the vagina or taken orally, meaning in terms of convenience, it’s already a winner.  If you’re done with having to remember to take the pill every day and also cringe at the thought of the coil, then this convenient contraceptive could be the answer to all of your prayers!

Remember, the only contraceptive that also protects you from sexually transmitted infection is the condom!

What is the contraceptive injection?

The contraceptive injection contains a hormone called progestogen which is similar to the hormone our body produces.

There are three types of injection;

  • Depo-Provera is the most commonly given in the UK and lasts for 13 weeks
  • Sayana Press also lasts for 13 weeks and is a newer option which can be self-injected
  • Noristerat  only lasts 8 weeks and is not commonly used in the UK.

Check out our blog comparing Depo-Provera and Sayana press.

How effective is the contraceptive injection?

The contraceptive injection is in the group of long-acting reversible contraceptives which have the highest protection rates against pregnancy. With perfect use, i.e. you don’t miss or are late for a jab, the injection is 99% effective.

How does the contraceptive injection work?

The injection steadily releases the hormone progestogen into your bloodstream. It prevents pregnancy in three ways – by stopping ovulation, by making the fluid in your cervix thicker (which makes it more difficult for sperm to enter the womb), and by preventing the lining of your womb thickening enough for an embryo to grow in it.

How do I get started on the contraceptive injection?

You can get the injection from your GP, practice nurse or local sexual health clinic. You can also now buy the Sayana Press injection through The Lowdown website.

You will be asked questions about your past medical history and your family history. It is important to make sure there is no risk of pregnancy when you start the injection so you should avoid sex or use another method of contraception from your last period or in the 3 weeks leading up to the injection.

You can then start the injection at any time during your period cycle. If you have it within the first five days of your cycle, you will be protected from pregnancy straight away.  Any other time in your cycle and you’ll need to use condoms for 7 days before it is effective. 

If you are switching from another hormonal method of contraception you should seek advice from a healthcare professional about when to start and whether to use additional contraception for the first 7 days. 

You can have the injection straight after giving birth or pregnancy. The contraceptive injection is safe to use while breastfeeding and has no effect on milk production.

You will be given the injection as you would a standard jab.

  • Depo-Provera can also sometimes be given in the buttock or arm.
  • Sayana Press is injected beneath the skin at the front of the thigh or abdomen. You can be taught how to give yourself the injection, rather than having a doctor or nurse give it to you. 

Talk to one of our friendly doctors

How do I stop the contraceptive injection?

Before you get the injection, it’s good to know that it can take between several months to a year for your fertility to return to normal after stopping. 

To stop, all you need to do is not have your next injection – if you don’t want to get pregnant then you should use another method of contraception from the day that your next injection would have been due. 

Always remember to take folic acid and vitamin D (buy from Amazon) if you are planning a pregnancy. These are Amazon affiliate links for supplements our doctors recommend – we earn a small commission too ❤️

Contraceptive injection pros and cons


  • A contraceptive that doesn’t need to be taken daily
  • It’s not affected by other medicines including antibiotics
  • It is not affected by vomiting or diarrhoea
  • Doesn’t interrupt sex
  • Great for stopping periods, 47% of women at 12 months of using had no bleeding. This may also help people with endometriosis, heavy bleeding or premenstrual syndrome (PMS)
  • Safe to use whilst breastfeeding and straight after pregnancy


  • The injection can impact your periods, causing them to be heavier, lighter, shorter or irregular which may not be acceptable to you.
  • Those at risk of weight gain – see section below
  • Potential impact on bone health – see section at end of blog

Who should use the contraceptive injection?

People who:

  • cannot use contraception that contains oestrogen
  • cannot remember to take a pill every day
  • are breastfeeding
  • want their periods to stop or get lighter

Who shouldn’t use the contraceptive injection?

People who:

  • want their fertility to return to normal immediately after finishing on a contraceptive or planning pregnancy in the next year
  • don’t want their periods to change
  • are at risk of osteoporosis (we talk about what that means in a later section)
  • are needle phobic
  • are on blood thinners like warfarin should try the Sayana Press rather than Depo-Provera as less chance of severe bruising
  • have breast cancer
  • severe liver disease

Check out the contraception reviews | The Lowdown

Side effects

As with all contraceptive methods, people may experience a range of different side effects or none at all. The injection can’t be removed from your body. If you have any side effects, you have to be prepared for them to continue during the eight or 13 week period, and for some time afterward.

The below side effects are some of the most frequently reported from users of the contraceptive injection;

  • Vaginal dryness 
  • Enlarged breasts 
  • Tender breasts 
  • Vaginal discharge 
  • Back pain 
  • Loss of sex drive

Check out our reviews for more information on possible side effects of the injection.

How will the contraceptive injection affect my periods?

The contraceptive injection can impact your periods, causing them to be heavier, lighter, shorter or irregular. The majority of women experience no periods altogether. In research studies nearly 50% of women have no periods at all after using the injection for 12 months. These side effects are temporary and your period should go back to normal within a few months of your last injection, although for some women this can take up to a year after stopping.

After the injection has been given, you will only need to go back to your doctor or nurse if you have any problems or when you need a new injection. If you are using the Sayana Press (which you injected yourself at home), you only have to go back to the clinic annually because you will be given a year’s supply.

What are the issues about weight gain with the injection?

The injection is the only method of contraception where weight gain is a proven potential side effect that women should be counselled for. If you are under 18 with a BMI of over 30 when you begin using the injection or if you gain more than 5% of your body weight within six months of starting the injection as you are more likely to continue gaining weight. 

What does this mean to me? We suggest that you keep a close eye on your weight during the first 6-12 months of using the injection. If your weight is going up and you are unhappy with it then the contraceptive injection may not be right for you.

See our blog all about weight gain and loss on contraception.

What are the issues about bone health and osteoporosis?

This is a really good question and often one that confuses contraception users as well as doctors and nurses alike. Unfortunately, at The Lowdown we hear of people being turned down for the injection based on this issue of bone health. Hopefully, this section can help dispel the myths around how the injection affects bone health.

We talk about bone health in terms of bone mineral density (BMD) which is how strong or thick your bones are. This can be affected by lots of things including getting older, being very underweight, smoking, low physical activity, drugs like steroids… the list goes on… The injection is linked with a small drop in your bone mineral density which recovers when you stop using it. 

Osteoporosis is a term for a medical condition where the bones become brittle and fragile. This puts you at risk of breaking bones.  The contraceptive injection does not give you osteoporosis. There were no links found between using the injection and getting broken bones. 

Why all the worry? If people are at risk of getting osteoporosis, you don’t want to have any extra bone thinning even if it is just whilst on the contraceptive injection. This means that people with the following risk factors should probably only use the injection for the shortest period of time. 

  • If you or a close family member have osteoporosis
  • If you have very low weight or anorexia
  • If you are a heavy smoker
  • If you are a heavy drinker
  • If you are on long-term steroids

If you haven’t fully finished growing yet then you might want to look at other contraceptive methods until you have, usually around 18 years old but we are all different. If you’re over 50 you’ll be advised to switch to a different method until the age of 55 or the menopause. 

But remember it is your choice and you have the right to decide about your risks. Being pregnant isn’t great for your bones either!

If you want the injection, look at ways to keep bones healthy, for example, stopping smoking, doing exercise or taking vitamin D is great for your bones. You will have a regular review with your doctor or nurse to check you are doing all you can to keep your bones strong.

  1. FSRH Clinical Guideline: Progestogen-only Injectable (December 2014, Amended October 2020)
  2. NHS. Contraceptive injection.
  3. FSRH Clinical Guideline: Contraception After Pregnancy (January 2017, amended October 2020)
  4. Said S, Omar K, Koetsawang S, Kiriwat O, Srisatayapan Y, Kazi A, Ajmal F, Wynter HH, Pretnar-Darovec A, Benitez IB. A multicentered phase III comparative clinical trial of depot-medroxyprogesterone acetate given three-monthly at doses of 100 mg or 150 mg: II. The comparison of bleeding patterns. World Health Organization. Task Force on Long-Acting Systemic Agents for Fertility Regulation Special Programme of Research, Development and Research Training in Human Reproduction. Contraception. 1987 Jun;35(6):591-610. 
  5. National Institute for Health and Clinical Excellence (NICE). Long-acting reversible contraception: subcutaneous depot medroxyprogesterone acetate (DMPA‑SC). Evidence summary [ESNM31]Published: 28 January 2014

Maddie is an English Language and Linguistics graduate who is passionate about writing. She writes fun and informative content on the weird and wonderful sides of contraception!