Etonogestrel contraceptive implant (Nexplanon)

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The etonogestrel implant is to prevent pregnancy.

Read the manufacturer's information leaflet from inside the pack before having the implant.

As with most hormonal contraceptives, side-effects include breast discomfort, fluid retention and an increase in acne.

Type of medicineProgestogen
Used forContraception
Also calledNexplanon®
Available asImplant

Etonogestrel is a progestogen, which is a female sex hormone similar to the progesterone hormone made naturally by your ovaries. An implant containing etonogestrel is a long-acting, effective and convenient form of contraception. The implant is a small flexible tube which is put under the surface of your skin on your upper arm. It releases etonogestrel slowly into your bloodstream. Each implant will provide contraception for up to three years. Nexplanon® is the brand name of the etonogestrel implant prescribed in the UK at present.

Etonogestrel works mainly by stopping ovulation (the release of an egg from the ovary). It also changes the lining of your womb (uterus) to make it less likely that an egg would attach to it, even if an egg were to fertilise. In addition, the mucus which forms a plug in your cervix becomes thicker. This stops sperm getting through to the uterus to fertilise an egg.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before having Nexplanon® it is important that your doctor knows:

  • If you think you could already be pregnant.
  • If you have any problems with the way your liver works.
  • If you have a problem with your arteries, called arterial disease.
  • If you have an ovarian cyst, or any vaginal bleeding other than your normal monthly period.
  • If you have systemic lupus erythematosus (this is an inflammatory condition, often called SLE).
  • If you have ever had an ectopic pregnancy or if you have developed severe itching or jaundice (yellowing of your skin or the whites of your eyes) during a pregnancy.
  • If you have had breast cancer or a cancer that you have been told is dependent on a sex hormone.
  • If you have a rare inherited blood disorder called porphyria.
  • If you have ever had an allergic reaction to a medicine.
  • If you are taking any other medicines, including those available to buy without a prescription, herbal and complementary medicines. This is because some medicines interfere with the way progestogen contraceptives work.
  • Before you are given the implant you will be asked to read the printed information leaflet from the implant package. The manufacturer's leaflet will give you important information about the implant and will provide a full list of the side-effects which you may experience from it. If, as a result of reading the leaflet, you have any questions, please discuss them with your doctor/nurse before you have the implant.
  • The implant will be inserted for you by a person who has been specially trained. A check will be made to ensure it is inserted correctly. Once this is confirmed, it is effective straightaway.
  • The implant is usually first inserted within five days of a period starting, to ensure that you are not pregnant. It will be put in the inner side of your upper arm. You will be given an injection of local anaesthetic to numb your skin, and a special needle will be used to put the implant in place. The area around the implant may be bruised and sore for a few days, but the wound will soon heal just like any other small cut.
  • You will be given a User Card which contains some details for you to keep. This will note the date the implant was inserted and will give a suggested date for it to be removed/replaced.
  • The release of progestogen from the implant will usually cause changes to the pattern of your periods. During the first few months, it is common to have irregular bleeding. This usually settles after the first year, but it may remain. Sometimes periods are heavier and longer than before, and sometimes periods become infrequent and light, or even stop altogether. One in five women with the implant have no bleeding.
  • If you do develop irregular bleeding, mention it to your doctor. Irregular bleeding can occasionally be due to another reason - for example, an infection, which may need to be treated.
  • You may gain a little weight. Eating a well-balanced diet and taking regular exercise can help minimise this, but if it is a concern to you, discuss it with your doctor.
  • It is important to check your breasts regularly for any lumps or bumps. Speak with your doctor if you notice any changes.
  • If at any time you suspect that you may be pregnant, make an appointment to see your doctor as soon as possible. You should also make an appointment to see your doctor if you notice any changes to the feel of the implant, or to the look of the skin around where the implant was inserted.
  • Some medicines can reduce the effectiveness of this contraceptive. These include medicines for epilepsy, medicines to treat fungal infections, the herbal preparation St John's wort, and medicines used to treat tuberculosis (TB). Tell the doctor that you have a progestogen implant if you are prescribed any other medicines. If you buy any medicines 'over the counter', ask the pharmacist for advice.
  • Please note: the implant will not protect you against HIV (AIDS) or any other sexually transmitted diseases.
  • The implant can be taken out at any time if you request removal. It loses its effect immediately after being removed. If you do not want to become pregnant, you must use another form of contraception straightaway afterwards.
  • A replacement implant is needed every three years if you wish to continue with this form of contraception. It requires a small procedure under local anaesthetic to remove the old implant and put in a new one.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with etonogestrel implants. You will find a full list in the manufacturer's information leaflet that has been given to you. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Very common Nexplanon® side-effects (these affect more than 1 in 10 women)
What can I do if I experience this?
HeadacheAsk your pharmacist to recommend a suitable painkiller
Vaginal infections, acne, increased weight, breast tenderness, irregular periodsIf you are concerned about any of these, speak with your doctor
Common Nexplanon® side-effects (these affect less than 1 in 10 women)What can I do if I experience this?
Feeling sick, wind, abdominal painThis does not usually last for long, but in the meantime, stick to simple meals
Pain near the implantThis should pass as the wound heals
Change in appetite, lack of interest in sex, mood changes, hot flushes, feeling dizzy or tired, hair thinning, painful periods, flu-like symptomsIf troublesome, speak with your doctor

If you experience any other symptoms which you think may be due to the implant, speak with your doctor or pharmacist for advice.

If you are having an operation or any dental treatment, tell the person carrying out the treatment about all the medicines you are using.

If you have any questions about your medicines, ask your pharmacist.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Hannah Gronow
Document ID:
13622 (v2)
Last Checked:
Next Review:
The Information Standard - certified member

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