Oestrogen for symptoms, progestogen to protect the endometrium
Expansion
The governing rule: oestrogen relieves symptoms; progestogen protects the endometrium. A woman with a uterus needs both. After hysterectomy, oestrogen alone.
Benefits: relief of vasomotor symptoms, urogenital atrophy and sexual dysfunction, improved quality of life, and reduced osteoporotic fracture while taken.
Risks
- Venous thromboembolism: raised with oral preparations, not with transdermal, which is why transdermal is preferred in those with risk factors
- Breast cancer: a small increased risk with combined HRT, related to duration, and falling after stopping. Oestrogen alone carries little or no increase
- Stroke: slightly raised with oral, not transdermal
- Endometrial cancer if oestrogen is unopposed
“Transdermal avoids first pass metabolism, and therefore avoids the clotting risk.”
Timing matters: started within 10 years of the menopause or before 60, the balance favours benefit, including possible cardiovascular benefit. Started later, risks outweigh benefits.
Contraindications: current or past breast cancer, oestrogen dependent cancer, undiagnosed vaginal bleeding, untreated endometrial hyperplasia, active venous thromboembolism, active liver disease and pregnancy.
Premature ovarian insufficiency is different: HRT is recommended until at least the average age of menopause, and the usual risk discussion does not apply.