A woman can get pregnant if a man’s sperm reaches one of her eggs (ova). Contraception tries to stop this happening by keeping the egg and sperm apart or by stopping egg production. One method is the implant.
The contraceptive implant is a small flexible tube about 40mm long that’s inserted under the skin of your upper arm. It’s inserted by a trained professional, such as a doctor, and lasts for three years.
The implant stops the release of an egg from the ovary by slowly releasing progestogen into your body. Progestogen also thickens the cervical mucus and thins the womb lining. This makes it harder for sperm to move through your cervix, and less likely for your womb to accept a fertilised egg.
At a glance: facts about the contraceptive implant
- If implanted correctly, it’s more than 99% effective. Fewer than one woman in 1,000 who have the implant as contraception for three years will get pregnant.
- It’s very useful for women who know they don’t want to get pregnant for a while. Once the implant is in place, you don’t have to think about contraception for three years.
- It can be useful for women who can’t use contraception that contains oestrogen.
- It’s very useful for women who find it difficult to take a pill at the same time every day.
- If you have side effects, the implant can be taken out. You can have the implant removed at any time, and your natural fertility will return very quickly.
- When it’s first put in, you may feel some bruising, tenderness or swelling around the implant.
- In the first year after the implant is fitted, your periods may become irregular, lighter, heavier or longer. This usually settles down after the first year.
- A common side effect of the implant is that your periods stop (amenorrhoea). It’s not harmful, but you may want to consider this before deciding to have an implant.
- Some medications can make the implant less effective, and additional contraceptive precautions need to be followed when you are taking these medications (see Will other medicines affect the implant?).
- The implant does not protect against sexually transmitted infections (STIs). By using condoms as well as the implant, you’ll help to protect yourself against STIs.
How the implant works
The implant steadily releases the hormone progestogen into your 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 (entrance to 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
The implant can be put in at any time during your menstrual cycle, as long as you and your doctor are reasonably sure you are not pregnant. In the UK, Nexplanon is the main contraceptive implant currently in use. Implants inserted before October 2010 were called Implanon. Since October 2010, insertion of Implanon has decreased as stocks are used up, and Nexplanon has become the most commonly used implant.
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 CT (computerised tomography) 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, thin, flexible tube about 4cm long. 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.
When it starts to work
If the implant is fitted during the first five days of your menstrual cycle, you will be immediately protected against becoming pregnant. If it is fitted on any other day of your menstrual cycle, you will not be protected against pregnancy for up to seven days, and should use another method, such as condoms.
After giving birth
You can have the contraceptive implant fitted after you have given birth, usually after three weeks.
- If it is fitted on or before day 21 after the birth, you will be immediately protected against becoming pregnant.
- If it is fitted after day 21, you will need to use additional contraception, such as condoms, for the following seven days.
It is safe to use the implant while you are breastfeeding.
After a miscarriage or abortion
The implant can be fitted immediately after a miscarriage or an abortion, and you will be protected against pregnancy straight away.
Who can use the implant
Most women can be fitted with the contraceptive implant.
It 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
- have diabetes with complications
- have cirrhosis or liver tumours
- are at risk of osteoporosis
The main advantages of the contraceptive implant are:
- it works for three years
- the implant does not interrupt sex
- it is an option if you cannot use oestrogen-based contraception, such as the combined contraceptive pill, contraceptive patch or vaginal ring
- you do not have to remember to take a pill every day
- the implant is safe to use while you are breastfeeding
- your fertility should return to normal as soon as the implant is removed
- implants offer some protection against pelvic inflammatory disease (the mucus from the cervix may stop bacteria entering the womb) and may also give some protection against cancer of the womb
- the implant may reduce heavy periods or painful periods after the first year of use
- after the contraceptive implant has been inserted, you should be able to carry out normal activities
Using a contraceptive implant may have some disadvantages, which you should consider carefully before deciding on the right method of contraception for you. These include:
Your periods may change significantly while using a contraceptive implant. Around 20% of women using the implant will have no bleeding, and almost 50% will have infrequent or prolonged bleeding. Bleeding patterns are likely to remain irregular, although they may settle down after the first year.
Although these changes are not harmful, they may not be acceptable for some women. Your GP may be able to help by providing additional medication if you have prolonged bleeding.
Side effects that some women report are:
- breast tenderness
- changes in mood
- loss of sex drive
These side effects usually stop after the first few months. If you have prolonged or severe headaches or other side effects, tell your doctor.
Some women put on weight while using the implant, but there is no evidence to show that the implant causes weight gain.
Will other medicines affect the implant?
Some medicines can reduce the implant’s effectiveness. These include:
- medication for HIV
- medication for epilepsy
- complementary remedies, such as St John’s Wort
- an antibiotic called rifabutin (which can be used to treat tuberculosis)
- an antibiotic called rifampicin (which can be used to treat several conditions, including tuberculosis and meningitis)
These are called enzyme-inducing drugs. If you are using these medicines for a short while (for example, rifampicin to protect against meningitis), it is recommended that you use additional contraception during the course of treatment and for 28 days afterwards. The additional contraception could be condoms, or a single dose of the contraceptive injection. The implant can remain in place if you have the injection.
Women taking enzyme-inducing drugs in the long term may wish to consider using a method of contraception that isn’t affected by their medication.
Always tell your doctor that you are using an implant if you are prescribed any medicines. Ask your doctor or nurse for more details about the implant and other medication.
In rare cases, the area of skin where the implant has been fitted can become infected. If this happens, the area will be cleaned and may be treated with antibiotics.
Where you can get the contraceptive implant
Contraception is free to everyone through the NHS. Places where you can get contraception include:
- some GP surgeries – talk to your GP or practice nurse
- contraception clinics
- some young people’s services - call 0300 123 7123 for more information
If you’re under 16 years old
Contraception services are free and confidential, including for people under the age of 16.
If you’re under 16 and want contraception, the doctor, nurse or pharmacist won’t tell your parents (or carer) as long as they believe you fully understand the information you’re given, and your decisions.
Doctors and nurses work under strict guidelines when dealing with people under 16. They’ll encourage you to consider telling your parents, but they won’t make you.
The only time that a professional might want to tell someone else is if they believe you’re at risk of harm, such as abuse. The risk would need to be serious, and they would usually discuss this with you first.