Copper IUD Safety in Hashimoto Thyroiditis
A copper IUD is safe and appropriate for patients with Hashimoto thyroiditis on levothyroxine, with no direct contraindications or interactions between the device and thyroid disease or thyroid hormone replacement. 1
Safety Profile for Autoimmune and Immunosuppressed Patients
- Copper IUDs are explicitly recommended for patients with autoimmune conditions, including those on immunosuppressive therapy, with no restrictions on use 2, 3
- Immunosuppression is not a contraindication to IUD placement, and historical concerns about increased infection risk in immunocompromised patients have not been substantiated by evidence 2
- The only infection risk occurs during the first 20 days after insertion, not beyond this period, regardless of immune status 2, 4
- For patients with systemic lupus erythematosus (another autoimmune condition) on corticosteroids, IUDs are specifically preferred over hormonal contraceptives 1, 2
No Interaction with Levothyroxine
- There is no pharmacologic interaction between copper IUDs and levothyroxine therapy 3
- The copper IUD is completely hormone-free with no systemic hormonal effects that could interfere with thyroid function or thyroid hormone replacement 3
- Unlike combined hormonal contraceptives, copper IUDs do not affect thyroid-binding globulin or alter levothyroxine requirements 3
Critical Bleeding Considerations
Increased menstrual blood loss is the primary concern with copper IUDs and requires specific management in patients with Hashimoto thyroiditis:
Expected Bleeding Pattern Changes
- Copper IUDs increase menstrual bleeding and cramping, particularly during the first several months after insertion 3, 5, 6
- This increased bleeding may persist even with long-term use and is the most common reason for discontinuation 4, 6
- Approximately 50% of women continue using the copper IUD after 5 years, indicating that many tolerate the bleeding changes 4
Iron Status Management
- Baseline iron studies (ferritin, CBC) should be obtained before insertion, particularly important given that hypothyroidism itself can be associated with anemia 3
- Monitor iron status at 3-6 months post-insertion and annually thereafter, as chronic increased menstrual blood loss can lead to iron deficiency anemia 3
- Consider prophylactic iron supplementation if ferritin is low-normal (<30 ng/mL) at baseline 3
- NSAIDs can be used for 5-7 days during bleeding episodes to reduce menstrual blood loss and cramping 3, 6
When to Consider Levonorgestrel IUD Instead
If the patient has any of the following, strongly consider a levonorgestrel IUD over copper IUD:
- Pre-existing iron deficiency anemia or low ferritin 3, 7
- Heavy baseline menstrual bleeding (menorrhagia) 3, 7
- Concurrent anticoagulation therapy (though not typical in Hashimoto's) 3, 7
- History of severe dysmenorrhea 7
The levonorgestrel IUD significantly decreases menstrual bleeding (with 35% of women experiencing amenorrhea after 2 years) and is progestin-only with no estrogen-related risks 7, 5, 6
Insertion Considerations
- No special precautions are required for IUD insertion in patients with Hashimoto thyroiditis 1
- Routine antibiotic prophylaxis before insertion is unnecessary 5, 6
- STI screening can be performed on the day of insertion 2
- The device can be inserted at any time during the menstrual cycle if pregnancy can be reasonably excluded 1, 6
Contraindications (Unrelated to Hashimoto's)
Absolute contraindications to copper IUD placement include:
- Current pregnancy 1
- Current or recent (within 3 months) pelvic inflammatory disease 1, 6
- Active purulent cervicitis, gonorrhea, or chlamydia infection 3
- Uterine anomalies that distort the cavity incompatible with insertion 3