Is Mirena (levonorgestrel‑releasing intrauterine system) suitable for a woman without contraindications, and what are the insertion procedure, follow‑up schedule, common side‑effects, and alternative long‑acting reversible contraceptive options?

Mirena (Levonorgestrel-Releasing Intrauterine System)

Overview and Suitability

Mirena is a highly effective long-acting reversible contraceptive suitable for women of all ages, including nulliparous women and adolescents, with a failure rate of less than 1% and FDA approval for 5 years (though effective for up to 7 years). 1, 2 The device releases 20 micrograms of levonorgestrel per 24 hours into the uterine cavity and provides both contraceptive and therapeutic benefits. 1

Key Contraindications to Screen For:

• Current or recent (within 3 months) pelvic inflammatory disease 3, 2
• Puerperal sepsis 3
• Septic abortion 3
• Pregnancy 3

Safety Profile:

• Safe for nulliparous adolescents and does not cause tubal infertility 1
• Rapid return to fertility after removal 1
• Small infection risk limited to first 20-21 days post-insertion 1, 2

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Insertion Procedure and Timing

When to Insert:

Mirena can be inserted at any time if you are reasonably certain the woman is not pregnant. 3 Waiting for the next menstrual period is unnecessary. 3

Backup Contraception Requirements:

• Within first 5 days of menses: No backup needed 3
• After day 5 of menses: Abstinence or backup contraception for 7 days 3
• Postpartum (<6 months, amenorrheic, fully breastfeeding): No backup needed 3
• Postpartum (≥21 days, not breastfeeding): Backup for 7 days 3
• Post-abortion (first 7 days): Backup for 7 days unless placed at time of surgical abortion 3

Special Timing Considerations:

• Can be inserted immediately postpartum (including post-cesarean) 3
• Can be inserted immediately post-abortion (first or second trimester) 3
• When switching from copper IUD after day 5 of cycle, consider emergency contraceptive pills at insertion due to residual sperm 3

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Follow-Up Schedule

Routine Follow-Up:

• No specific routine follow-up visits are mandated by guidelines 3
• Women should be advised to return promptly if they experience: heavy bleeding, cramping, pain, abnormal vaginal discharge, or fever 3

String Checks:

• Women can be taught to check for strings themselves 3
• If strings are not visible, ultrasound should be obtained to confirm device position 1

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Common Side Effects and Management

Bleeding Pattern Changes (Most Common):

Unscheduled spotting or light bleeding is expected during the first 3-6 months and is generally not harmful. 3 Over time, bleeding decreases, with approximately 50% of women experiencing amenorrhea by 2 years. 3

Management Algorithm for Irregular Bleeding:

1. Provide reassurance that bleeding changes do not indicate contraceptive failure 1
2. Rule out complications if clinically indicated:
   • Check strings to confirm device position 1
   • Obtain ultrasound if strings not visible 1
   • Pregnancy test if clinical suspicion (though failure rate is only 0.68% in years 6-8) 1
   • Evaluate for STDs, displacement, or uterine pathology (polyps, fibroids) 3
3. Offer symptomatic management with NSAIDs for 5-7 days during bleeding episodes 3, 1
4. If bleeding persists and is unacceptable: Counsel on alternative methods and offer removal 3, 1

Amenorrhea Management:

• Amenorrhea requires no medical treatment—provide reassurance 3
• If regular bleeding pattern changes abruptly to amenorrhea, consider ruling out pregnancy 3
• If amenorrhea is unacceptable to the patient, counsel on alternatives 3

Other Common Side Effects:

• Dysmenorrhea typically improves or disappears due to endometrial suppression 4
• Breast tenderness (if present with concurrent oral progestin, discontinue the oral progestin immediately) 1
• Device does not cause clinically elevated prolactin levels 1

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Therapeutic Benefits Beyond Contraception

Mirena is FDA-approved and first-line treatment for heavy menstrual bleeding, achieving 71-95% reduction in menstrual blood loss. 1, 2 This makes it particularly valuable for:

• Women with menorrhagia 1, 2, 5
• Adolescents requiring menstrual suppression when estrogen is contraindicated 1
• Patients on anticoagulation who need to minimize bleeding 1
• Endometrial protection in hormone replacement therapy 6

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Alternative Long-Acting Reversible Contraceptive Options

Other Hormonal IUDs:

• Kyleena (19.5 mg levonorgestrel): Lower hormone content, approved for 5 years, may have less bleeding reduction than Mirena 2
• Skyla (13.5 mg levonorgestrel): Lowest dose, approved for 3 years, not studied for heavy menstrual bleeding 1
• Liletta (52 mg levonorgestrel): Similar to Mirena, approved for 3 years 1

Copper IUD:

• Non-hormonal option effective for 10-12 years 3
• May increase menstrual bleeding and cramping (unlike levonorgestrel IUDs) 1
• Category 1 (no restrictions) for parous women 1

Etonogestrel Implant:

• Single rod with 68 mg etonogestrel 3
• Effective for 3 years 3
• Requires 7 days backup if inserted after day 5 of menses 3
• Does not reduce menstrual bleeding as effectively as Mirena 1

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Special Clinical Situations

Pelvic Inflammatory Disease During Use:

• Treat PID with antibiotics; IUD does not need immediate removal 3
• Reassess in 24-48 hours; if no improvement, continue antibiotics and consider removal 3
• Treatment outcomes do not differ between women who retain versus remove the IUD 3

Pregnancy with IUD in Place:

• Remove IUD as soon as possible if strings are visible 3
• Removal improves pregnancy outcomes (reduces spontaneous abortion, preterm delivery, infection) 3
• If IUD cannot be removed, risks for adverse outcomes are substantial 3

Cardiovascular Disease:

• Category 1 (no restrictions) for controlled hypertension 1
• Category 2 (benefits outweigh risks) for severe hypertension, history of VTE, or multiple CV risk factors 1
• Minimal systemic hormone exposure (only 4-13% of oral contraceptive exposure) 1

Extended Use Beyond 5 Years:

• Effective for up to 7 years with cumulative failure rate of 0.68% in years 6-8 1, 2
• Can continue use if patient desires and no complications present 1

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Critical Pitfalls to Avoid

• Do not prescribe oral progestin in addition to Mirena—this causes excessive progestin exposure and breast tenderness without therapeutic benefit 1
• Do not remove IUD for breast tenderness alone—address the underlying cause (usually redundant oral progestin) 1
• Do not use Skyla for heavy menstrual bleeding—only Mirena has established efficacy for this indication 1
• Do not delay insertion waiting for menses—can insert anytime if reasonably certain patient is not pregnant 3
• Do not assume bleeding changes indicate contraceptive failure—mechanism of contraception remains independent of bleeding patterns 1