Cardiovascular, Metabolic, and Thrombotic Risks of Oral Medroxyprogesterone Acetate

Cardiovascular & Metabolic Effects

• Oral medroxyprogesterone acetate (MPA) worsens lipid profiles compared with alternative progestins, especially when combined with estrogen, attenuating the HDL‑raising effect of estrogen therapy. 1, 2, 3
• MPA impairs vasomotor function, which may increase cardiovascular risk in women using the drug. 1, 4, 5
• MPA negatively influences carbohydrate metabolism and reduces glucose tolerance, contributing to metabolic dysregulation. 1, 4
• When co‑administered with ethinyl estradiol, MPA can elevate blood pressure, worsen renal function, and activate the renin‑angiotensin system. 1, 2

Thrombotic & Cerebrovascular Risks

• Injectable depot MPA and combined hormonal contraceptives containing MPA raise the risk of venous thromboembolism (VTE) and should be avoided in women with chronic coronary disease or a history of stroke. 6, 7
• Combined estrogen‑MPA therapy doubles the relative risk of VTE (RR ≈ 2.0) and increases the incidence of stroke. 8, 3

Common Adverse Reactions (Oral MPA Alone)

• Breakthrough bleeding and spotting are frequently reported. 3
• Alterations in cervical secretions occur with oral MPA use. 1
• Patients may experience weight fluctuations (gain or loss). 3
• Fluid retention and peripheral edema are observed adverse effects. 3
• Acne can develop during therapy. 3
• Alopecia or hirsutism may arise. 3

Serious Adverse Events (Estrogen‑MPA Combination)

• A modest increase in invasive breast cancer incidence and related mortality has been documented. 8
• Unopposed MPA raises endometrial cancer risk, whereas estrogen‑MPA combinations protect against endometrial hyperplasia. 8
• The combination is associated with a higher incidence of gallbladder disease. 8
• Post‑menopausal women using estrogen‑MPA have an elevated risk of dementia. 8
• Moderate harm in the form of increased urinary incontinence has been reported. 8

Emerging Safety Signals (2024 Pharmacovigilance)

• Reports of bone pain and osteonecrosis have emerged as possible adverse events. 3
• Dental caries have been identified as a new safety signal. 6
• Paradoxical decreases in blood pressure have been observed in a subset of patients. 3

Contraindications

• A history of thromboembolic events, stroke, or myocardial infarction contraindicates MPA use. 3
• Underlying liver disease is a contraindication. 3

Clinical Alternatives & Guideline Recommendations

• MPA remains the only progestin with proven full effectiveness in inducing a secretory endometrium when combined with estrogen. 1, 2, 4, 5
• The European Society for Human Reproduction and Embryology (ESHRE) now recommends natural micronized progesterone as a safer alternative, particularly regarding cardiovascular and thrombotic risk profiles. 1, 2, 4, 5