Progesterone (Micronized) — Women's Hormones
Bioidentical micronized progesterone for endometrial protection and symptom management in hormone replacement therapy. FDA-approved with Grade A evidence.
Overview
Micronized progesterone (Prometrium) is bioidentical progesterone used in HRT for women with intact uterus. It provides essential endometrial protection when estrogen is prescribed, preventing endometrial hyperplasia and cancer. Unlike synthetic progestins, bioidentical progesterone has favorable effects on sleep, mood, and cardiovascular markers. The REPLENISH and KEEPS studies demonstrate safety and efficacy. Bedtime dosing is preferred due to sedative effects that can improve sleep quality.
Indications
- Endometrial protection when using systemic estrogen (REQUIRED if uterus intact)
- Sleep disturbance in perimenopause/menopause
- Anxiety and mood support during hormone transition
- Luteal phase support in perimenopause
- Part of combined HRT regimen
Mechanism of Action
Micronized progesterone absorbed in GI tract; micronization improves bioavailability
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Micronized Progesterone (Prometrium) | 100 mg | Daily at bedtime | Standard continuous regimen with estrogen. Prevents breakthrough bleeding after initial months |
| Micronized Progesterone (Prometrium) | 200 mg | Daily at bedtime | Higher dose for perimenopause with heavier symptoms or as cyclic regimen |
| Micronized Progesterone (Prometrium) | 200 mg | Days 1-12 of each month | Results in monthly withdrawal bleed. Preferred by some women transitioning into menopause |
| Progesterone Suppository | 100-200 mg | Daily at bedtime | Alternative if oral not tolerated. Higher uterine levels, lower systemic exposure |
Safety & Contraindications
- Required when using systemic estrogen in women with intact uterus to prevent endometrial hyperplasia
- Contraindicated with peanut allergy (Prometrium contains peanut oil)
- May cause drowsiness - take at bedtime
- Avoid in active thromboembolism or liver disease
- Bioidentical progesterone has better cardiovascular profile than synthetic progestins
- Use continuous or cyclic regimen based on patient preference