Mirena IUD Contraindications
Absolute Contraindications (Category 4)
The only absolute contraindication to Mirena insertion is confirmed or suspected pregnancy, due to the risk of severe pelvic infection and septic spontaneous abortion. 1, 2, 3
Additional absolute contraindications include:
- Current breast cancer — Breast cancer is a hormonally sensitive tumor, making the levonorgestrel-releasing IUD contraindicated in women with active disease 1
- Persistently elevated β-hCG levels or malignant gestational trophoblastic disease 1
- Distorted uterine cavity from congenital or acquired anatomical abnormalities that would prevent proper device placement 4
- Current cervical or endometrial cancer awaiting treatment — The device will likely need removal at time of treatment, and insertion poses increased risk of infection, perforation, and bleeding 1, 4
Relative Contraindications (Category 3)
These conditions warrant careful consideration but are not absolute contraindications:
- Active sexually transmitted infections (chlamydia or gonorrhea) or purulent cervicitis — Category 3 due to increased risk of pelvic inflammatory disease with insertion 3, 4. However, STI screening can be performed on the day of insertion with treatment afterward without device removal if needed 3
- Past breast cancer with no evidence of disease for 5 years — Category 3, though concerns about disease progression may be less with LNG-IUD than with combined oral contraceptives 1
- Unexplained vaginal bleeding (suspicion for serious condition) before evaluation — Category 4 for initiation, Category 2 for continuation. The device does not need removal before evaluation, but underlying pathology must be ruled out 1, 5, 6
Important Category 2 Conditions (Advantages Generally Outweigh Risks)
- Cervical intraepithelial neoplasia — Theoretical concern exists that LNG-IUD might enhance progression, though evidence is limited 1
- Undiagnosed breast mass — Requires evaluation but not absolute contraindication 1
- Heavy or prolonged bleeding — Category 2 for initiation, though the LNG-IUD is actually beneficial for treating menorrhagia 1, 4
Critical Clinical Pitfalls
Irregular bleeding is extremely common in initial Mirena users and may mask underlying cervical or endometrial pathology. 5, 6 Proper evaluation of irregular vaginal bleeding, including cervical cytology, should be performed before insertion and repeated if symptoms persist beyond the expected adjustment period of 3-6 months 5, 6
Past pelvic inflammatory disease, HIV infection, immunosuppression, and nulliparity are NOT contraindications to Mirena use. 1, 7 The risk of pelvic infection is confined to the first 20-21 days after insertion 3