Mirena intra-uterine device (IUD)

Introduction

Mirena is a progesterone-based intra-uterine device used as a contraceptive or to manage menorrhagia / PV bleeding
it acts as a long-acting acting reversible contraception (LARC) due to 52mg of levonorgestrel

it has a 99% efficacy rate as a contraceptive
contraceptive effect is via:
- thickening cervical mucus
- thinning the uterine lining which reduces implantation success
- in addition, particularly in the 1st year, it may prevent ovulation

a Mirena lasts for up to 8 years when used for contraception¹⁾²⁾
- if used on those 45 or older when it is inserted, it can often remain in place for contraception until menopause is reached
when using it to treat heavy menstrual bleeding, endometriosis, or as part of menopausal hormone therapy (MHT/HRT), it may need to be replaced or removed after 5 years, although if used for heavy bleeding, it can be used up to 8 years if it effectively controls bleeding
- hormone dosage decreases over time, which may allow heavy periods or symptoms to return
- for MHT, it should be replaced at the 5-year mark to safely balance oestrogen effects

¹⁾

²⁾