First-lineMirena (52 mg) / Kyleena (19.5 mg) / Jaydess (13.5 mg)

Levonorgestrel IUS

Intrauterine progestogen system (LARC)

First-line for HMB and endometrial protection on HRT.

Intrauterine

First-line for

  • Heavy menstrual bleeding
  • Contraception (LARC)
  • Endometrial protection with oestrogen HRT
  • Endometrial hyperplasia without atypia

Mechanism

Local LNG release → profound endometrial atrophy; some anovulation (dose-dependent); mucus thickening.

"Local, low-dose, long-acting"

  • Mirena 52 mg → 8 y contraception / 5 y HMB & HRT
  • Kyleena 19.5 mg → 5 y
  • Jaydess 13.5 mg → 3 y

Dosing

Insertion
Any time if reasonably certain not pregnant; immediate cover if within days 1–7

Contraindications

  • AbsoluteCurrent pelvic infection, unexplained uterine bleeding, distorted cavity, current breast cancer

Side effects

  • Irregular bleeding → oligo-/amenorrhoea
  • Ovarian cysts (usually functional)
  • Perforation ~1/1000
  • Expulsion 3–5%

Fetal & maternal notes

  • Remove if pregnancy — ↑ ectopic and miscarriage risk if retained

Key interactions

  • Enzyme inducers

    OK

    No effect (local delivery)

Clinical pearls

  • 💡 Endometrial protection: only 52 mg IUS licensed
  • 💡 Check threads at 4–6 weeks post-insertion

Content last reviewed: REPLACE_ME (e.g. 2026-07)

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For educational use only

Not medical advice. Verify dosing against the BNF and your local trust guidelines before prescribing.