Can You Check 17-Hydroxyprogesterone with Mirena IUD?
Yes, you can absolutely check 17-hydroxyprogesterone (17-OHP) levels while using a Mirena levonorgestrel-releasing intrauterine device—the Mirena IUD does not interfere with 17-OHP testing and does not need to be removed for this laboratory assessment.
Why This Is Safe and Appropriate
The Mirena IUD releases levonorgestrel locally into the uterine cavity, with minimal systemic absorption. While some levonorgestrel does enter the bloodstream (mean levels around 260 pg/ml initially, declining to 129 pg/ml after one year 1), this does not interfere with 17-OHP measurement since:
- 17-OHP is a different hormone: It's a precursor in the steroid hormone pathway, primarily produced by the corpus luteum and adrenal glands
- Levonorgestrel is a synthetic progestin: It's chemically distinct from 17-hydroxyprogesterone and doesn't cross-react in standard 17-OHP assays
- The Mirena works primarily locally: Its contraceptive effect is mainly through local endometrial changes, not systemic hormonal suppression 2
Important Clinical Context
Ovarian Function Remains Largely Intact
After long-term Mirena use (6+ years), 78.5% of women maintain ovulatory cycles 2. This means:
- The corpus luteum still forms and produces 17-OHP
- Ovarian steroidogenesis continues normally
- 17-OHP levels reflect actual ovarian/adrenal function
When 17-OHP Testing Is Typically Ordered
17-OHP is commonly measured for:
- Congenital adrenal hyperplasia screening (especially 21-hydroxylase deficiency)
- Evaluation of hirsutism or virilization
- Assessment of corpus luteum function in early pregnancy 3, 4
The Mirena IUD does not affect any of these clinical scenarios or the interpretation of results.
Common Pitfall to Avoid
Do not confuse this with 17-alpha hydroxyprogesterone caproate (17-OHPC), which is a completely different medication—a synthetic progestogen previously used (and now withdrawn by the FDA) for prevention of preterm birth 5. That medication is unrelated to:
- The Mirena IUD
- The laboratory test for endogenous 17-hydroxyprogesterone
Bottom Line
Proceed with 17-OHP testing as clinically indicated. The presence of a Mirena IUD requires no special consideration, timing adjustments, or removal for accurate laboratory assessment.