---
title: "Contraceptive implant and injection: Uses & Side Effects"
description: "Compare the implant and injection for effectiveness, bleeding, side effects, duration and return to fertility."
url: https://healthanswers.co.uk/treatments/contraceptive-implant-and-injection/
robots: noindex
---

# Contraceptive implant and injection: Uses & Side Effects

Treatments

Compare the implant and injection for effectiveness, bleeding, side effects, duration and return to fertility.

Written by HealthAnswers editorial team Medically reviewed by [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/) Reviewed 1 August 2026

## Quick answer

Should I choose the contraceptive implant or injection? The implant is a small progestogen rod placed under the arm and is over 99% effective for up to 5 years. The contraceptive injection lasts 8 to 13 weeks depending on the product. Both can change bleeding; fertility usually returns quickly after implant removal but may take up to a year after stopping injections.

## Who is this page for?

This page is for people in the UK who want a plain-English overview of Contraceptive implant and injection, including when to seek help and what NHS care usually involves. It explains general information, not what is wrong with you personally.

## Who should skip this page?

Skip this page if you need a diagnosis, a prescription, or emergency care. It cannot replace a GP, pharmacist, NHS 111 or 999. If you are in immediate danger, call 999; for urgent advice that is not life-threatening, call 111 in England, Scotland or Wales, or use your GP out-of-hours service in Northern Ireland.

On this page 3 sections

## Key facts about contraceptive implant and injection

- Neither method protects against sexually transmitted infections.
- Irregular or absent bleeding is common with both methods.
- Some medicines and herbal remedies can affect contraceptive suitability or effectiveness.

## The implant

A trained clinician places a flexible rod under local anaesthetic. It can be felt under the skin and removed through a small procedure. Irregular bleeding is the most common reason for review.

## The injection

Injections are repeated on schedule. Long-term use can temporarily reduce bone density, which generally recovers after stopping; individual risks and benefits should be discussed.

## Choosing between them

Consider how you feel about a small procedure, injections, unpredictable bleeding, repeat appointments and how quickly you might want pregnancy.

## ! Important safety information for contraceptive implant and injection

Contact the fitting or prescribing service for troublesome bleeding, pregnancy concern, severe mood change or implant-site redness, swelling or discharge. Seek emergency help for severe allergic reaction or serious sudden symptoms.

## Common questions about contraceptive implant and injection

Which is more effective, implant or injection? Both are highly effective; the implant is over 99% effective and removes the risk of a late repeat injection. Will periods stop? They may stop, become irregular, lighter, heavier or more frequent. The pattern is difficult to predict before starting. How soon can I get pregnant afterwards? Fertility usually returns quickly after implant removal. After injections it may take up to a year, though some people conceive sooner.

## Sources

- [NHS — Methods of contraception](https://www.nhs.uk/contraception/methods-of-contraception/)
- [NHS — Contraceptive injections](https://www.nhs.uk/medicines/contraceptive-injections-medroxyprogesterone/)