Implanon is a small flexible rod inserted under the skin of the upper arm, releasing a progestogen steadily over several years. It is highly effective and requires nothing to remember day to day.
The trade-off is bleeding. Implants change bleeding patterns unpredictably, and unlike an intrauterine system, the pattern that emerges in the first months tends to be the pattern that persists. That is the main thing to weigh before choosing this method.
Common hormonal medicine side effects
- Changes to bleeding. This is by far the most common effect and the most common reason people stop. Bleeding may be irregular, prolonged, more frequent, lighter, or stop altogether.
- Headaches
- Breast tenderness
- Acne, or a change in skin
- Mood changes
- Abdominal or pelvic discomfort
- Changes in sexual desire
Because these methods contain a progestogen only and no oestrogen, they can often be used by people who cannot take combined pills, including those with migraine with aura and some who smoke over the age of 35. Confirm your own situation with a clinician rather than assuming.
Bruising, tenderness or swelling at the insertion site is usual for a few days afterwards.
Bleeding, mood, skin, weight and cycle changes
Bleeding is unpredictable and varies widely between people. Roughly, some have infrequent or no bleeding, some have regular bleeding, and some have frequent or prolonged bleeding. There is no way to know in advance which you will get.
Prolonged or troublesome bleeding is treatable, and it is worth asking rather than assuming removal is the only option. See implant bleeding side effects.
Acne may appear or worsen in some people and improve in others. Mood changes are reported and are a legitimate reason to review the method. Weight change is reported, though evidence that implants directly cause substantial weight gain is limited.
Serious warning signs that need medical attention
Contact your clinic for:
- Signs of infection at the insertion site: increasing pain, redness, swelling, heat or discharge
- Not being able to feel the implant. You should be able to feel it under the skin. If you cannot, use additional contraception and contact your clinic, as it may need locating.
- The implant appearing to have moved, or becoming visible or painful
- A missed period with abdominal pain, which needs assessment
- Heavy or prolonged bleeding that is affecting you
- Yellowing of the eyes or skin, or a severe headache unlike your usual
Who may be at higher risk?
Tell your clinician about unexplained vaginal bleeding, liver conditions, a history of breast cancer, or medicines that may reduce effectiveness, including some epilepsy medicines, certain antibiotics such as rifampicin, and St John’s Wort. See St John’s Wort and birth control.
Implanon does not protect against sexually transmitted infections.
What to discuss with your doctor, pharmacist or clinic
- What can be done if the bleeding pattern is unmanageable?
- When is it due for replacement or removal?
- How do I check I can still feel it?
- Do any of my medicines reduce how well it works?
- How quickly does fertility return after removal?
Related contraception, HRT and hormonal medicine guides
- Hormonal contraception side effects
- Long-acting contraception side effects
- Birth control side effects
- Women’s health and hormonal medicine side effects
- Report a side effect in South Africa
See also contraceptive implant side effects, Nexplanon and implant removal.
Medical Disclaimer: This content is for informational and educational purposes only and does not constitute medical diagnosis, prescription, or professional advice. Always read the patient information leaflet and consult a qualified doctor or pharmacist regarding any medicine or health concern.