# The contraceptive implant

> A matchstick-sized rod in your arm that works for 5 years.

Category: Contraception · 4 min read · Written by the Splash team · Sources checked October 2026
URL: https://splash.care/learn/contraception/implant

## Quick answer

- Over 99% effective for 5 years.
- Fertility returns straight away after removal.
- Unpredictable bleeding is the main trade-off.
- Doesn’t protect against STIs.

The implant is a small flexible rod, around 4cm long, placed under the skin of your upper arm. It releases [Progestogen](https://splash.care/learn/glossary/progestogen) to stop [ovulation](https://splash.care/learn/glossary/ovulation), and it’s one of the most effective methods available.

**5 years** How long one implant works (NHS)

- Over 99% effective if replaced on time
- Nothing to remember day to day
- Can be removed any time; fertility returns straight away
- [Oestrogen](https://splash.care/learn/glossary/oestrogen)-free

## The bleeding lottery

Changes to periods are very common. Yours might get lighter, stop completely, become [irregular](https://splash.care/learn/cycle-basics/irregular-cycles) with [spotting](https://splash.care/learn/glossary/spotting), or – for some – heavier or longer. It can be unpredictable, but it’s not usually harmful.

Other reported effects include [headaches](https://splash.care/learn/period-care/migraines), [sore breasts](https://splash.care/learn/body-literacy/breast-changes), [acne](https://splash.care/learn/body-literacy/acne-skin) and weight gain, though the NHS says there isn’t enough evidence the implant causes these.

> **Splash says:** add your implant date to the app with a reminder for year 5. Future you will be grateful!

**Myth:** The implant can travel around your body.

**Fact:** It can occasionally shift a few centimetres from where it was placed, which a clinician can sort out. It doesn’t wander off on adventures.

### When to see a doctor

Contact a GP or sexual health clinic if the site becomes red, swollen or painful, you can’t feel the implant, bleeding changes are bothering you, or you think you might be pregnant.

> Only condoms (external and internal) help protect against STIs. Every other method on this page prevents pregnancy only.

## Sources

1. [NHS – What is the contraceptive implant?](https://www.nhs.uk/contraception/methods-of-contraception/contraceptive-implant/what-is-it/)
2. [NHS – Side effects and risks of the implant](https://www.nhs.uk/contraception/methods-of-contraception/contraceptive-implant/side-effects-and-risks/)
3. [NHS – How well contraception works at preventing pregnancy](https://www.nhs.uk/contraception/choosing-contraception/how-well-it-works-at-preventing-pregnancy/)

This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).