Medroxyprogesterone Acetate (Provera) for Abnormal Uterine Bleeding
For abnormal uterine bleeding (AUB) due to ovulatory dysfunction, medroxyprogesterone acetate should be administered orally at 10 mg daily for 10 days in the luteal phase of the menstrual cycle for at least 3 months. 1, 2
Mechanism of Action
Medroxyprogesterone acetate works through several mechanisms to treat AUB:
- Transforms proliferative endometrium into secretory endometrium when administered to women with adequate endogenous estrogen 3
- Inhibits pituitary gonadotropin secretion, which prevents follicular maturation and ovulation 3
- Stabilizes the endometrial lining, reducing irregular shedding and bleeding 1
- Counteracts the effects of unopposed estrogen on the endometrium, particularly important in anovulatory bleeding 1, 4
Dosing Regimens for AUB
Recommended Dosing:
- Anovulatory bleeding: 10 mg oral medroxyprogesterone acetate daily for 10 days each month for at least 3 months 1, 2
- Alternative regimen for anovulatory bleeding: 10 mg daily from days 16-25 of the menstrual cycle (10-day protocol), which has shown better regulation of menstrual cycles compared to longer protocols 2
- For ovulatory dysfunctional uterine bleeding: 5-10 mg three times daily from days 5-25 of the menstrual cycle 5
Treatment Duration:
- Initial treatment should continue for at least 3 cycles 2
- For endometrial hyperplasia, treatment may be extended to 6 months for optimal results 6
Efficacy
- Significantly reduces menstrual blood loss in both anovulatory and ovulatory dysfunctional uterine bleeding 5
- Effectively regulates menstrual cycles with the 10-day protocol showing better results than longer protocols 2
- Achieves regression rates of 72.7-100% in cases of endometrial hyperplasia after 6 months of therapy 6
- Reduces both the volume and duration of bleeding 5
Clinical Considerations
- Not recommended for secondary amenorrhea or dysfunctional uterine bleeding when oral therapy is more appropriate 3
- Particularly effective for anovulatory bleeding in adolescents and perimenopausal women 1
- May be used as part of combination therapy with other agents for difficult-to-control bleeding 1
- Should be considered after ruling out structural causes of AUB through appropriate imaging 7
Important Caveats
- Endometrial sampling should be considered in patients with risk factors for endometrial cancer before starting therapy 7
- For acute heavy bleeding episodes, high-dose estrogen therapy may be more appropriate than progestins alone 1
- Surgical options (endometrial ablation or hysterectomy) should be considered for patients who fail medical management 1
- Always rule out bleeding disorders such as von Willebrand's disease, which may present similarly to dysfunctional uterine bleeding 1
- Transvaginal ultrasound should be performed to exclude structural causes of bleeding before attributing AUB to hormonal dysfunction 7