Nexplanon side effects: what to know

The implant releases etonogestrel, a progestogen that prevents pregnancy. Because it changes hormonal signals to the ovaries and the lining of the womb, bleeding may become lighter, heavier, irregular, more frequent, or absent. These patterns can change over time and do not by themselves show whether the implant is working.

Some people notice headache, nausea, tender breasts, acne, or a change in mood. Local tenderness or a small bruise is more closely related to insertion. Other causes, including pregnancy, infection, anaemia, thyroid problems, or a separate medicine, can produce similar symptoms, so persistent or troubling changes deserve assessment.

Write down bleeding days, pain, headaches, mood symptoms, and any medicines or supplements you take. Check that you can feel the rod in the upper arm without pressing hard, and avoid trying to move it. Simple measures such as rest, fluids, and a cool pack over a tender insertion area may help. A clinician can discuss symptom treatment or whether another contraceptive method, such as a hormonal coil, fits your preferences.

Arrange prompt medical advice for very heavy or prolonged bleeding, severe or worsening arm pain, increasing redness or swelling, discharge, fever, a rod that feels bent or cannot be felt, or a new lump near the site. Seek urgent help for severe chest pain, sudden breathlessness, coughing blood, one-sided weakness, or a severe allergic reaction. Take a pregnancy test and contact a clinician if pregnancy is possible, especially with lower abdominal pain or dizziness.

Ask which symptom treatments are suitable for you, whether another condition or medicine could explain the change, how the rod position will be checked, and what alternatives are available if side effects continue.