What is the recommended oral medroxyprogesterone acetate regimen for treating abnormal vaginal bleeding in a non‑pregnant adult woman without contraindications?

Oral Medroxyprogesterone Acetate for Abnormal Uterine Bleeding

For acute abnormal uterine bleeding in a non-pregnant adult woman, administer medroxyprogesterone acetate 20 mg orally every 8 hours for 3 days (9 doses total), combined with a single depot medroxyprogesterone acetate 150 mg intramuscular injection. 1

Acute Bleeding Management

Primary Regimen for Immediate Control

• Combination therapy achieves bleeding cessation within 2.6 days on average, with 100% of women stopping bleeding within 5 days. 1
• Administer depot medroxyprogesterone acetate (DMPA) 150 mg intramuscularly in the gluteal or deltoid muscle as a single dose 1, 2
• Simultaneously prescribe oral medroxyprogesterone acetate 20 mg every 8 hours for exactly 3 days (total of 9 doses) 1
• This dual-route approach provides both immediate high-dose progestogen effect (oral) and sustained 3-month coverage (depot injection) 1, 2

Expected Outcomes and Patient Counseling

• Mean time to complete bleeding cessation is 2.6 days, though some women may experience light spotting through day 5 1
• Side effects are infrequent with this short-course regimen 1
• Patient satisfaction is consistently high with this outpatient protocol 1

Chronic or Recurrent Bleeding Management

For Ovulatory Dysfunction (AUB-O)

Use medroxyprogesterone acetate 10 mg orally daily from cycle day 16 through day 25 (10-day protocol) for at least 3 consecutive cycles. 3

• The 10-day protocol (days 16-25) is superior to the 15-day protocol (days 11-25) for achieving regular menstrual cycles and stopping abnormal bleeding 3
• Three treatment cycles are typically sufficient to achieve bleeding cessation 3
• This regimen mimics luteal phase progesterone support and corrects the hormonal imbalance underlying ovulatory dysfunction 3

Alternative Chronic Regimen

• Medroxyprogesterone acetate 10 mg daily for 12-14 days per month is the gold standard for proven endometrial protection when used as part of hormone replacement therapy 4, 5
• For continuous suppression without withdrawal bleeding, use medroxyprogesterone acetate 2.5-5 mg daily continuously 4, 5

Critical Clinical Considerations

Pre-Treatment Requirements

• Confirm the patient is not pregnant before initiating any medroxyprogesterone regimen 6, 2
• Rule out structural causes (fibroids, polyps, malignancy) and coagulopathy before attributing bleeding to hormonal causes 6
• Undiagnosed vaginal bleeding is a contraindication until malignancy is excluded 6, 2

Absolute Contraindications

• Known or suspected pregnancy (fetal exposure may cause low birth weight) 2
• Known or suspected breast malignancy 6, 2
• Active thromboembolic disorders or cerebral vascular disease 2
• Active liver dysfunction or disease 6, 2
• Undiagnosed abnormal vaginal bleeding (until cause determined) 6, 2

Common Pitfalls to Avoid

• Do not use medroxyprogesterone acetate alone without first ruling out pregnancy—this is the most critical safety check 6, 2
• Avoid prescribing depot medroxyprogesterone for longer than necessary, as prolonged use (>2 years) may contribute to bone mineral density loss 2
• Do not assume all abnormal bleeding is hormonal—structural and hematologic causes must be excluded first 6
• The 15-day protocol (days 11-25) is less effective than the 10-day protocol (days 16-25) for ovulatory dysfunction 3

Expected Side Effects

• Menstrual irregularities are common initially, with 57% of women developing amenorrhea by 12 months of depot use 2
• Weight gain, headache, nervousness, abdominal discomfort, and dizziness may occur 2
• Breakthrough bleeding or spotting occurs in approximately 23% of patients during acute treatment 1

Monitoring and Follow-Up

Acute Treatment Protocol

• Contact patient at day 5 to confirm bleeding cessation 1
• If bleeding persists beyond 5 days, reassess for structural pathology or coagulopathy 1
• The depot injection provides 3 months of contraceptive coverage, requiring repeat injection every 90 days if continued 2

Chronic Treatment Protocol

• Assess response after 3 cycles of the 10-day regimen 3
• If bleeding pattern normalizes, consider transitioning to maintenance therapy or discontinuation based on underlying etiology 3
• Monitor hemoglobin if significant blood loss occurred prior to treatment 3

Alternative Progestogen Options

When Medroxyprogesterone is Contraindicated or Not Tolerated

• Norethindrone acetate 1 mg daily offers superior cardiovascular and metabolic profile compared to medroxyprogesterone acetate 4
• Oral micronized progesterone 200 mg daily for 12-14 days per cycle is preferred when available due to lower cardiovascular and thrombotic risk 4, 5, 7
• Levonorgestrel intrauterine system provides local endometrial suppression with minimal systemic effects for women experiencing systemic progestogen side effects 4

Comparative Safety Profile

• Medroxyprogesterone acetate has documented adverse effects on lipid profiles, vasomotion, and carbohydrate metabolism compared to natural progesterone 4
• Despite less favorable metabolic profile, medroxyprogesterone acetate remains widely used due to extensive safety data, proven efficacy, and widespread availability 4
• Micronized progesterone is preferred over synthetic progestins when cardiovascular or thrombotic risk is a concern 5, 7