What is Mirena?
Mirena is a small, flexible T-shaped intrauterine device (IUD) placed in the uterus by a healthcare provider. It steadily releases levonorgestrel (a progestin hormone) locally over up to 8 years (FDA-approved for 8 years for contraception, 5 years for heavy menstrual bleeding). It’s one of the most effective long-term, reversible birth control methods available.
How Mirena Works
- Thickens Cervical Mucus: Prevents sperm from reaching the egg.
- Thins Uterine Lining: Inhibits implantation and reduces menstrual bleeding.
- May Suppress Ovulation: In some users, it prevents egg release (though not its primary mechanism).
Key Benefits
✅ Highly Effective: >99% effective at preventing pregnancy.
✅ Long-Lasting: Works continuously for up to 8 years.
✅ Low Maintenance: “Set-it-and-forget-it” contraception.
✅ Reduces Menstrual Bleeding: Often leads to lighter periods or amenorrhea (no periods).
✅ Reversible: Fertility typically returns quickly after removal.
✅ Non-Estrogen: Safe for those who cannot use estrogen-based methods.
Potential Side Effects & Risks
*Common (Usually improve in 3-6 months):*
- Irregular bleeding/spotting
- Headaches, breast tenderness
- Mood changes, acne
- Cramping after insertion
Less Common:
- Expulsion (IUD partially/completely slips out)
- Perforation (rare; occurs during insertion)
- Ovarian cysts (usually benign and resolve)
- Increased risk of pelvic inflammatory disease (PID) in the first 21 days post-insertion
Serious (Seek immediate care if):
- Severe pelvic pain, fever, or chills (signs of infection/PID)
- Pregnancy (including ectopic pregnancy risk)
- Missing IUD strings
Who Can Use Mirena?
Appropriate for:
- Most women, including adolescents and those who haven’t had children.
- Women needing long-term contraception or heavy period management.
- Breastfeeding women (after 6 weeks postpartum).
Not Recommended for:
- Current pelvic infection or unexplained uterine bleeding.
- Uterine abnormalities distorting the cavity.
- Known/suspected pregnancy or breast cancer.
- Allergy to levonorgestrel or Mirena components.
FAQs: Mirena IUD
Q1: Does insertion hurt?
A: Most experience cramping (like a strong period) during insertion. Pain management (NSAIDs, local anesthetic) is available. Cramping usually subsides within days.
Q2: Can Mirena cause weight gain?
A: Clinical trials show no significant average weight gain linked to Mirena. Individual responses vary.
Q3: Will my periods stop completely?
A: Many users experience lighter periods; ~20% stop menstruating after 1 year. This is safe and reversible.
Q4: Can I use tampons or menstrual cups?
A: Yes, but check IUD strings regularly. Change tampons frequently and be cautious with cup removal to avoid dislodging strings.
Q5: How is Mirena removed?
A: A provider gently pulls the strings. Removal takes minutes, and fertility typically returns rapidly.
Q6: Does Mirena protect against STIs?
A: No. Use condoms to reduce STI risk.
Q7: What if I get pregnant with Mirena?
A: Contact your provider immediately. Ectopic pregnancy risk is low but possible. Removal is needed if pregnancy occurs.
Scientific References & Sources
- FDA Approval & Labeling: U.S. Food and Drug Administration (FDA). (2024). MIRENA® (levonorgestrel-releasing intrauterine system) Prescribing Information. Link
- Long-Term Efficacy: Creinin, M. D., et al. (2023). Levonorgestrel 52 mg Intrauterine System Efficacy Through 8 Years of Use. Obstetrics & Gynecology, 142(5), 1007–1014. DOI: 10.1097/AOG.0000000000005384
- Heavy Menstrual Bleeding Treatment: Kaunitz, A. M., et al. (2018). Levonorgestrel-Releasing Intrauterine System for Heavy Menstrual Bleeding: A Systematic Review. Obstetrics & Gynecology, 132(4), 1007–1014. DOI: 10.1097/AOG.0000000000002898
- Safety Profile: Heinemann, K., et al. (2015). Safety of levonorgestrel 52 mg intrauterine system compared to copper IUDs: a systematic review. Contraception, 91(1), 22–39. DOI: 10.1016/j.contraception.2014.10.006
- ACOG Practice Bulletin: American College of Obstetricians and Gynecologists. (2021). Long-Acting Reversible Contraception: Implants and Intrauterine Devices. Practice Bulletin No. 186. DOI: 10.1097/AOG.0000000000004586