Oral Micronized Progesterone 200 mg: Dosing and Administration
For endometrial protection in postmenopausal women on estrogen therapy, oral micronized progesterone 200 mg should be administered as a single daily dose at bedtime for 12-14 consecutive days per 28-day cycle 1, 2.
Primary Indications and Dosing Regimens
Endometrial Protection in Menopausal Hormone Therapy
The most established use of oral micronized progesterone 200 mg is for endometrial protection in women with an intact uterus receiving estrogen therapy:
- Sequential regimen: 200 mg orally once daily at bedtime for 12-14 days per 28-day cycle 1
- Continuous regimen: 100 mg orally once daily 1
- Duration: Proven safe and effective for up to 5 years 3
This dosing provides adequate endometrial protection equivalent to other progestational agents while offering a superior safety profile regarding cardiovascular risk and breast cancer compared to synthetic progestins 1, 3, 4.
Premature Ovarian Insufficiency (Iatrogenic)
In adolescents and young women with chemotherapy- or radiation-induced POI:
- Sequential oral regimen: 200 mg daily for 12-14 days every 28 days when combined with continuous transdermal or oral 17β-estradiol 5
- Alternative: 10 mg MPA for 12-14 days per month (second choice) 5
- Micronized progesterone is the first-choice progestogen in this population due to lower cardiovascular and thromboembolic risk 5
Secondary Amenorrhea
For treatment of secondary amenorrhea:
- 400 mg orally once daily at bedtime for 10 days 2
This higher dose is FDA-approved specifically for inducing withdrawal bleeding in amenorrheic women.
Administration Considerations
Timing and Technique
Bedtime administration is critical for oral micronized progesterone 200 mg 2. This timing:
- Minimizes the mild sedative effects (drowsiness, dizziness) that occur due to progesterone's neurosteroid activity 1, 6, 7
- Maximizes patient tolerability
- Achieves peak serum concentrations within 2-3 hours of administration 2
For patients with swallowing difficulties: Take with a full glass of water while standing 2.
Bioavailability Factors
The micronized formulation significantly enhances oral bioavailability compared to non-micronized progesterone 2, 8. Key pharmacokinetic points:
- Peak serum concentrations (Cmax) at 200 mg dose: 38.1 ± 37.8 ng/mL 2
- Time to peak: approximately 2.3 hours 2
- Food increases bioavailability - can be taken with or without food, though food enhances absorption 2
- Highly protein-bound (96-99%) to albumin and transcortin 2
Clinical Scenarios Where 200 mg Dose is NOT Recommended
Preterm Birth Prevention
Do not use oral micronized progesterone 200 mg for preterm birth prevention in singleton pregnancies with prior spontaneous preterm birth 9. Instead:
- 17-alpha hydroxyprogesterone caproate 250 mg IM weekly is the evidence-based choice for this indication 9
- Vaginal progesterone (90 mg gel or 200 mg suppository) is appropriate for short cervix without prior PTB 10, 9
Short Cervix Without Prior PTB
For asymptomatic women with singleton gestation and transvaginal cervical length ≤20 mm before 24 weeks:
- Vaginal progesterone (90 mg gel or 200 mg suppository) is recommended, not oral 10
- Oral route lacks evidence for this specific indication
Alternative Routes and Formulations
When oral administration is contraindicated or not tolerated:
Vaginal micronized progesterone:
- 200 mg daily for 12-14 days every 28 days provides endometrial protection 5
- May achieve adequate endometrial effects with fewer systemic side effects 1
- Off-label for menopausal hormone therapy but established for luteal support 1
Transdermal progesterone: Does NOT provide adequate endometrial protection and should not be used 3.
Safety Profile and Monitoring
Oral micronized progesterone 200 mg has a favorable safety profile compared to synthetic progestins:
- Lower breast cancer risk than synthetic progestins 4, 7
- Lower cardiovascular and thromboembolic risk 5, 7
- Does not attenuate cardiovascular benefits of estrogen 4
- Main side effect: mild, transient drowsiness (minimized by bedtime dosing) 6, 7
No routine laboratory monitoring is required for progesterone levels, as serum concentrations do not reliably predict endometrial protection 1.
Common Pitfalls to Avoid
Do not use continuous daily 200 mg dosing for endometrial protection - this exceeds the evidence-based dose (100 mg daily for continuous regimens) 1
Do not prescribe for preterm birth prevention in women with prior spontaneous preterm birth - this is not the appropriate indication for oral progesterone 9
Do not forget bedtime administration - daytime dosing increases sedation complaints and reduces tolerability 2, 6
Do not use in women without a uterus - progesterone is unnecessary for endometrial protection in hysterectomized women receiving estrogen 1, 11
Do not exceed 16 weeks of gestation when treating threatened miscarriage - beneficial effects are complete by 12 weeks, and prolonged exposure may have theoretical risks to offspring 12