Medroxyprogesterone for Managing Heavy Menstrual Bleeding
Medroxyprogesterone acetate (MPA) can effectively stop menstrual bleeding when administered at doses of 5-10 mg daily for 5-10 days during acute bleeding episodes, or as a 150 mg intramuscular injection combined with oral therapy for more severe cases. 1
Mechanism and Indications
Medroxyprogesterone acetate is FDA-approved for treating abnormal uterine bleeding due to hormonal imbalance in the absence of organic pathology. It works by:
- Stabilizing the endometrial lining
- Inducing secretory changes in the endometrium
- Preventing endometrial proliferation
- Promoting organized shedding of the endometrial lining
Treatment Regimens
The appropriate regimen depends on the clinical scenario:
For Acute Heavy Bleeding Episodes:
- First-line approach: MPA 5-10 mg daily for 5-10 days 1
- For severe acute bleeding: Consider combination therapy with depo-medroxyprogesterone acetate 150 mg intramuscular injection plus oral MPA 20 mg every 8 hours for 3 days (9 doses total) 2
For Chronic/Recurrent Heavy Menstrual Bleeding:
- For anovulatory bleeding: MPA 5-10 mg daily for 10 days each month for ≥3 months 3
- For ovulatory bleeding: MPA 5-10 mg three times daily from days 5-25 of the menstrual cycle 4
- Alternative regimen: MPA from days 16-25 of the menstrual cycle (10-day protocol), which has been shown to better regulate menstrual cycles and more frequently stop abnormal uterine bleeding compared to a 15-day protocol 5
Efficacy and Limitations
The CDC notes that when treating heavy menstrual bleeding:
- Before initiating therapy, underlying gynecological problems should be ruled out 6
- NSAIDs may be used for short-term treatment (5-7 days) 6
- Hormonal treatment with low-dose combined oral contraceptives or estrogen may be used for short-term treatment (10-20 days) 6
However, it's important to recognize that:
- Long-cycle progestogen therapy is inferior to levonorgestrel-releasing intrauterine systems (LNG-IUS), tranexamic acid, and ormeloxifene for reducing menstrual blood loss 7
- Short-cycle progestogen therapy during the luteal phase is inferior to tranexamic acid, danazol, and progestogen-releasing intrauterine systems 7
Clinical Pearls and Pitfalls
- Rule out structural causes: Before initiating MPA therapy, ensure that structural causes of bleeding (fibroids, polyps, malignancy) have been excluded 6
- Monitor response: If heavy bleeding persists despite treatment and is unacceptable to the patient, consider alternative contraceptive methods 6
- Treatment hierarchy: The LNG-IUS is more effective than oral progestogens for managing heavy menstrual bleeding (71-95% reduction versus lower rates with oral progestogens) 8
- Duration of therapy: For chronic management, treatment typically continues for at least 3 months to establish regular cycles 3
Special Considerations
- For women with completed childbearing who fail medical management, endometrial ablation may be considered as a less invasive alternative to hysterectomy 8
- For women with fibroids causing heavy bleeding, uterine artery embolization may be considered if medical therapy fails 8
- For perimenopausal women, cyclic progestin or cyclic conjugated equine estrogens for 25 days with concomitant MPA for days 18-25 may be effective 3
While MPA is effective for many women with abnormal uterine bleeding, treatment should be tailored based on the underlying cause, severity of bleeding, and patient preferences regarding contraception and future fertility.