How the Mirena works
The Mirena is a hormonal intrauterine device (IUD) that releases a small amount of progestogen directly into the uterus. It's over 99 per cent effective and lasts up to eight years. Because the hormone acts mainly locally, very little enters your bloodstream, which is why systemic side effects tend to be fewer than with the pill.
Beyond contraception, it's also used to treat heavy periods — many women find their periods become much lighter or stop altogether — and as part of menopausal hormone therapy.
Common side effects
The most common experience in the first three to six months is irregular spotting or bleeding as your body settles. After that, periods usually become lighter, and for many women stop. Some women notice hormonal-type side effects like breast tenderness, mood changes or headaches, though these are less common than with the pill and often improve with time.
Serious problems are uncommon. Concerns about long-term side effects are frequent online, but for most women the Mirena is well tolerated; if it doesn't suit you, it can be removed at any time and your cycle returns.
What to expect with insertion
Insertion is a quick in-person procedure done by a trained clinician. You may have cramping and some spotting for a few days afterwards. Taking simple pain relief beforehand can help. It's normal to have irregular bleeding for the first few months.
A GP can talk through whether the Mirena is right for you, counsel you on what to expect, and arrange the insertion. If you're considering it — for contraception, heavy periods, or both — a telehealth consult is a good first step.
Related condition
Contraception & the pill →References & sources
This content is general information and not a substitute for individual medical advice. Please consult a GP for your personal situation.
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