1. Hormonal IUDs (e.g. levonorgestrel: Mirena, Kyleena):
- These suppress ovulation in some, though not all, users.
- The endometrium is thinned, often eliminating cyclic bleeding.
- Progesterone is elevated locally, but not systemically.
- FSH and LH may not follow a typical ovulatory pattern.
In essence, hormonal IUDs mimic a "quiet" follicular phase hormonally, as the luteal surge and mid-cycle peak often do not occur..
2. Copper IUDs (e.g. Paragard):
- Do not suppress ovulation or hormones.
- Menstrual cycles remain largely normal and ovulatory.
- Menstrual phase should correspond to the phase of the menstrual cycle on the date of the collection
- Follicular phase: Days 6–13
- Ovulatory: Days 14-15 (brief window)
- Luteal phase: Days 15–28
3. Postmenopausal Women with IUDs:
- If confirmed postmenopausal (no periods for >12 months, elevated FSH), the IUD is irrelevant to hormone interpretation.
- Select postmenopausal phase, regardless of IUD.