Introduction
Contraceptive implants and injections are long-acting, effective methods of contraception. They are over 99% reliable in preventing pregnancy. This means that less than 1 woman in 100 who uses a contraceptive implant or injection will become pregnant each year.
The implant and injection work in the same way. They steadily release the hormone progestogen into a woman s bloodstream. Progestogen is similar to the natural hormone progesterone, which is released by a woman's ovaries during her period.
The continuous release of progestogen:
- stops a woman releasing an egg every month (ovulation)
- thickens the mucus from the cervix (neck of the womb), making it difficult for sperm to pass through to the womb and reach an unfertilised egg
- makes the lining of the womb thinner so that it is unable to support a fertilised egg
Things to consider
Both implants and injections can be given at any time during your menstrual cycle, as long as you and your doctor are reasonably sure you are not pregnant.
Read more about when contraceptive implants and injections are given.
The main advantages of contraceptive implants and injections are:
- You are protected against pregnancy soon after you receive the implant or get your first injection.
- Your fertility will return when you have the implant removed or stop having the injections.
However, in the first year of using these methods of contraception, your periods will often be disrupted and you may have other side effects, such as headaches, nausea and weight gain.
Read more about the disadvantages of contraceptive implants and injections.
Where can I get contraceptive implants and injections?
You can get an injection or implant at your GP surgery or a genitourinary medicine (GUM) or sexual health clinic. It will be given by a specially trained doctor or nurse.
Find sexual health services near you, including sexual health and GUM clinics.
Who can use them?
Most women can be fitted with the contraceptive implant or given the contraceptive injection.
They may not be suitable if you:
- think you might be pregnant
- want to keep having regular periods
- have bleeding in between periods or after sex
- have arterial disease or a history of heart disease or stroke
- have a blood clot in a blood vessel (thrombosis)
- have liver disease
- have migraines
- have breast cancer or have had it in the past
The contraceptive injection may also not be suitable if you:
- have diabetes with complications
- have cirrhosis or liver tumours
- are at risk of osteoporosis
Implants
In the UK, Nexplanon is the only contraceptive implant that is currently used. Implants inserted after October 2010 are called Nexplanon and implants inserted before this are called Implanon.
Both types of implant work in the same way, but Nexplanon is designed to reduce the risk of insertion errors and is visible on an X-ray or computerised tomography (CT) scan. There is no need for existing Implanon users to have their implant removed and replaced by Nexplanon ahead of its usual replacement time.
Nexplanon is a small (4cm), thin flexible tube. It is implanted under the skin of your upper arm by a doctor or nurse. A local anaesthetic is used to numb the area. The small wound made in your arm is closed with a dressing and does not need stitches.
Nexplanon works for up to three years before it needs to be replaced. You can continue to use it until you reach the menopause, when a woman s monthly periods stop at around 52 years of age. The implant can be removed at any time by a specially trained doctor or nurse. It only takes a few minutes to remove, using a local anaesthetic.
As soon as the implant has been removed, you will no longer be protected against pregnancy.
Injections
The contraceptive injection is usually given into a muscle in your bottom, although sometimes it may be given in a muscle in your upper arm. Two types of injection are available. They are:
- Depo-Provera - the most commonly used injection in the UK, effective for up to 12 weeks, after which another injection is given
- Noristerat - effective for up to eight weeks
