Levonorgestrel Intrauterine System
Key Points
- The levonorgestrel-releasing intrauterine contraception (LNG-IUS/LNG-IUC) is a T-shaped device inserted into the uterus that releases low-dose progestin locally — the most effective reversible contraception available (99.8% perfect and typical use).
- Brand options by duration: Mirena (7 years), Liletta (6 years), Kyleena (5 years), Skyla (3 years — smaller frame for adolescents/nulliparous).
- Dual indications: (1) Long-term contraception; (2) treatment of heavy menstrual bleeding (menorrhagia) — Mirena FDA-approved for up to 5 years for menorrhagia.
- Key complications: increased risk of ectopic pregnancy, IUC expulsion or misplacement, PID risk elevated in first 3 weeks after insertion, uterine perforation (rare).
- Patient education: check strings monthly at the cervix, attend early placement follow-up (commonly 4-6 weeks), and understand fertility returns immediately after removal.
Mechanism of Action
The LNG-IUS releases levonorgestrel (progestin) locally into the uterine cavity:
- Endometrial suppression: Prevents proliferation of the endometrium — thin lining reduces menstrual bleeding and endometrial cancer risk
- Cervical mucus thickening: Progestin thickens cervical mucus, preventing sperm penetration
- Suppression of ovulation (partial, depending on dose): Higher-dose devices (Mirena) may partially suppress ovulation
- Foreign body effect: The plastic T-frame creates a local inflammatory response that is spermicidal
Brand Comparison
| Brand | Duration | Frame Size | Notes |
|---|---|---|---|
| Mirena | Up to 7 years | Standard | Approved for menorrhagia treatment (up to 5 years); 20 mcg/day initial release |
| Liletta | Up to 6 years | Standard | Similar to Mirena; lower cost option |
| Kyleena | Up to 5 years | Smaller | Lower hormone dose; suitable for adolescents and nulliparous patients |
| Skyla | Up to 3 years | Smallest | Lowest dose (14 mcg/day); best for adolescents or short-term use |
Indications
| Indication | Notes |
|---|---|
| Long-term contraception | Highly effective for up to 7 years; immediate return to fertility after removal |
| Menorrhagia (heavy menstrual bleeding) | Mirena FDA-approved for treatment of menorrhagia — thins endometrium, reduces blood loss |
| Dysmenorrhea associated with endometriosis | Reduces menstrual pain and bleeding |
| Perimenopause | LNG-IUS during perimenopause controls abnormal and heavy bleeding; not contraindicated |
Benefits
- Highest effectiveness: Perfect and typical use effectiveness equal at 99.8% — no adherence required
- Amenorrhea: 6%–20% of users develop amenorrhea (absence of periods), depending on device hormone dose
- Reduced endometrial cancer risk: Prevents endometrial thickening
- No estrogen-related risks: Safe for patients who cannot use estrogen (smokers, hypertension, DVT history)
- Privacy: No visible packaging; nothing to do before intercourse
- Immediate return to fertility after removal
Complications
| Complication | Description | Nursing Action |
|---|---|---|
| Ectopic pregnancy risk | Progestin slows cilia in fallopian tubes, increasing ectopic risk if pregnancy occurs | Educate to report pregnancy symptoms immediately; check strings monthly |
| Expulsion or misplacement | Device expelled from uterus — especially high rate if placed immediately after placenta delivery | Educate patient to check strings monthly; contact provider if strings not felt or if can’t locate device |
| Pelvic inflammatory disease (PID) | Risk elevated in first 3 weeks after insertion; not significantly higher overall | Screen for STIs before insertion; educate to report fever, abnormal discharge, pelvic pain |
| Uterine perforation | Rare during insertion — device may extrude into peritoneal cavity | Educate to report heavy vaginal bleeding, severe cramping, fever after insertion |
| Abnormal bleeding | Irregular spotting common in first 3–6 months, especially with Mirena | Reassure patient; menstrual pattern typically improves after 3 months |
Contraindications
- Pregnancy (known or suspected)
- Uterine anomalies that distort the uterine cavity
- Current pelvic infection (PID, endometritis, cervicitis)
- Unexplained vaginal bleeding
- Reproductive tract cancers (cervical, uterine, ovarian)
- Breast cancer (hormone-sensitive)
- Liver disease or hepatic tumor
Pre-Insertion Nursing Responsibilities
- Screen for STIs (gonorrhea, chlamydia) before insertion — reduces PID risk
- Confirm no current pregnancy
- Obtain informed consent — discuss benefits, risks, complications, and alternative methods
- Assess for uterine anomalies (may require imaging prior to insertion)
- Educate patient about expected cramping and bleeding during and after insertion
- Arrange follow-up to confirm placement stability, commonly about 4-6 weeks after insertion
Patient Education
NCLEX Focus
Key patient education priorities: (1) check strings monthly at the cervix — contact provider if cannot feel them; (2) report pregnancy symptoms immediately (ectopic risk); (3) return to fertility is immediate after removal; (4) LNG-IUS does NOT protect against STIs; (5) irregular bleeding in first 3–6 months is expected.
- String check: Reach inside vagina to locate strings hanging from cervix — check monthly after menstruation
- Follow-up timing: Keep early postinsertion visit (often 4-6 weeks) to confirm continued correct placement
- STI protection: LNG-IUS does NOT protect against sexually transmitted infections — condoms recommended
- Pregnancy symptoms: Report nausea, breast tenderness, missed period — check for ectopic pregnancy
- Menstrual changes: Expect irregular spotting initially; amenorrhea is expected and normal with Mirena
Related Concepts
- long-acting-reversible-contraception — LNG-IUS is a core LARC method alongside copper IUD and contraceptive implant.
- progestin-only-contraceptives — LNG-IUS releases progestin locally; similar mechanisms to progestin-only pills and injection.
- benign-reproductive-growths — LNG-IUS may be used to manage endometriosis, adenomyosis, and uterine fibroids that cause menorrhagia.
- reproductive-system — Understanding uterine anatomy is essential for IUC insertion and monitoring.
- functional-reproductive-disorders — LNG-IUS treats dysmenorrhea and menorrhagia associated with endometriosis.
Self-Check
- A patient with an LNG-IUS reports she cannot feel the strings during her monthly check. What is the priority nursing instruction?
- A patient asks why the nurse is recommending condom use when she already has an LNG-IUS. How should the nurse respond?
- What is the advantage of Kyleena or Skyla over Mirena for an adolescent patient requesting an IUC?