Evidence‑Based Role of Megestrol Acetate in Acute Heavy Menstrual Bleeding

Emergency High‑Dose Progestin Management

In hemodynamically unstable women with uncontrolled menstrual hemorrhage, high‑dose oral or injectable progestin‑only agents (including megestrol acetate) can be employed as short‑term therapy to achieve rapid hemostasis (American College of Cardiology, Circulation 2018) 1.
A practical trigger for initiating high‑dose progestin is bleeding that saturates a large pad or tampon each hour for ≥ 4 hours (American College of Cardiology, Circulation 2018) 2.
When standard hormonal therapies are contraindicated—such as in patients with established cardiovascular disease—high‑dose progestin offers a viable alternative (American College of Cardiology, Circulation 2018) 1.
If non‑steroidal anti‑inflammatory drugs (NSAIDs) and tranexamic acid must be avoided because of thrombotic risk, high‑dose progestin is recommended (American College of Cardiology, Circulation 2018) 2.

Cyclic oral progestin regimens reduce menstrual blood loss by approximately 87 % in women with heavy bleeding (American College of Cardiology, Circulation 2018) [1][2].
Megestrol acetate demonstrates superior effectiveness in patients with markedly thickened endometrium (≥ 11 mm), where other progestins often fail to achieve adequate control (American College of Cardiology, Circulation 2018) [1][2].

If bleeding does not improve after an initial course of megestrol acetate, clinicians should reassess for structural uterine pathology and consider alternative therapeutic options (American College of Cardiology, Circulation 2018) 1.