Mirena: Indications and Usage
Mirena (levonorgestrel-releasing intrauterine system) is FDA-approved for contraception for up to 5 years and is highly effective for treating heavy menstrual bleeding (menorrhagia), with additional therapeutic benefits for dysmenorrhea and endometriosis. 1
Primary Indications
Contraception
- Mirena provides highly effective long-acting reversible contraception with a failure rate of less than 1%, making it one of the most reliable contraceptive methods available 1
- The 52 mg levonorgestrel formulation is approved for 5 years of use, though evidence suggests effectiveness extends up to 7 years 1
- Appropriate for all reproductive-age women, including nulliparous adolescents, as it does not cause tubal infertility 1
Heavy Menstrual Bleeding (Menorrhagia)
- The LNG-IUD is beneficial in treating menorrhagia, with evidence showing no increase in adverse effects and significant reduction in menstrual blood loss 1
- Studies demonstrate reductions in menstrual blood loss of up to 90% 2, 3
- More effective than oral medical therapy (norethisterone, medroxyprogesterone, mefenamic acid) for reducing heavy bleeding, with mean differences of 66.91 mL by alkaline haematin method and 55.05 points by PBAC scores 2
- Comparable effectiveness to endometrial ablation techniques for bleeding reduction, with similar satisfaction rates but better cost-effectiveness 2
Therapeutic Benefits Beyond Primary Indications
Gynecologic Conditions
- Endometriosis: LNG-IUD use decreases dysmenorrhea, pelvic pain, and dyspareunia in women with endometriosis 1
- Severe dysmenorrhea: Associated with reduction of dysmenorrhea symptoms 1
- Endometrial hyperplasia: Most women experience disease regression with LNG-IUD use, with no adverse health events reported 1
- Menorrhagia in thrombocytopenia: May be useful treatment for menorrhagia in women with severe thrombocytopenia 1
Bleeding Pattern Changes
- Women experience decreased menstrual bleeding over time, with 29.5% achieving amenorrhea within the first six cycles and approximately 44-50% by 6-12 months 4, 5
- Overall bleeding becomes less in volume, with many women experiencing amenorrhea, though menses become more irregular initially 1
Special Populations
HIV-Infected Women
- HIV infection is not a contraindication to IUD use and is classified as CDC category 2, meaning advantages generally outweigh theoretical or proven risks 1
- Exception: Women with advanced HIV disease (category 3) should use alternative contraceptive methods until immunologic and clinical status improves with antiretroviral therapy 1
- IUD use does not adversely affect HIV disease progression or increase HIV transmission risk to partners 1
Adolescents
- IUDs are now considered safe for nulliparous adolescents, as they do not cause tubal infertility 1
- Small risk of pelvic infection exists only during the first 21 days after insertion 1
- Can be inserted in asymptomatic adolescents at high risk of STI with screening on day of insertion; subsequent STI treatment can be provided without IUD removal 1
Important Clinical Considerations
Contraindications and Precautions
- Active pelvic infection or STI is a contraindication to insertion, but asymptomatic high-risk patients can have insertion with same-day screening 1
- Unexplained vaginal bleeding (category 4 for initiation): Must be evaluated before insertion to rule out pregnancy or underlying pathology such as pelvic malignancy 1
- Current breast cancer (category 4): Contraindicated due to hormonally sensitive nature of the tumor 1
- Cervical cancer awaiting treatment: Concern exists about increased risk for infection and bleeding at insertion 1
Acceptable Conditions for Use
- Heavy or prolonged bleeding (category 1 for initiation, category 2 for continuation) 1
- Uterine fibroids (category 2): Most women experience improvements in hemoglobin, hematocrit, and ferritin 1
- Cervical intraepithelial neoplasia (category 2): Theoretical concern exists about potential progression 1
Management of Bleeding Irregularities
- For unscheduled spotting or light bleeding with LNG-IUD: NSAIDs for 5-7 days of treatment 1
- For heavy or prolonged bleeding with LNG-IUD: NSAIDs for 5-7 days or hormonal treatment (if medically eligible) with COCs or estrogen for 10-20 days 1
- If bleeding disorder persists or woman finds it unacceptable, counsel on alternative methods 1