This is general health information only and is not a substitute for advice from your GP or healthcare professional.
1. What is menopausal hormone therapy (MHT)?
Menopausal hormone therapy (MHT) uses oestrogen, with or without a progestogen, to treat menopausal symptoms such as hot flushes, night sweats, and genitourinary symptoms. The type and route of MHT should be individualised according to symptoms, age, time since menopause, medical history, and cardiovascular and thromboembolic risk.
2. What is the difference between oral and transdermal MHT?
Oral MHT is taken as a tablet and passes through the liver before entering the systemic circulation. Transdermal MHT delivers oestrogen through the skin, usually as a patch or gel, avoiding first-pass metabolism in the liver. This difference can affect clotting factors, triglycerides, and other cardiovascular risk factors.
3. Which is safer for blood clots: oral or transdermal MHT?
Transdermal oestrogen is generally preferred for women who have an increased risk of venous thromboembolism (VTE). Oral oestrogen increases the risk of blood clots, whereas transdermal MHT, particularly at standard doses, has not been associated with the same increase in VTE risk.
4. Does oral MHT increase the risk of heart attack or cardiovascular disease?
For healthy women who start MHT before age 60 or within 10 years of menopause, MHT does not appear to increase overall cardiovascular disease risk, and some evidence suggests a possible reduction in coronary heart disease when started near menopause. MHT should not, however, be started specifically to prevent cardiovascular disease.
5. Does transdermal MHT have cardiovascular advantages over oral MHT?
Transdermal oestrogen has less effect on liver-produced clotting factors and is associated with a lower risk of VTE than oral oestrogen. It may therefore be preferred in women with cardiovascular or thromboembolic risk factors. However, direct randomised trials comparing cardiovascular outcomes between oral and transdermal MHT are limited.
6. Does MHT increase the risk of stroke?
Oral MHT can slightly increase stroke risk, particularly with increasing age and higher baseline cardiovascular risk. The risk appears to be lower with lower-dose and transdermal oestrogen. In healthy women younger than 60 years or within 10 years of menopause, the absolute increase in stroke risk is generally very small.
7. Who should preferentially consider transdermal MHT?
Transdermal MHT is generally preferred for women with increased VTE risk, including those with obesity, smoking, previous VTE, significant cardiovascular risk factors, or prolonged immobility. It may also be preferred in women with migraine, hypertension, high triglycerides, or certain liver conditions.
8. Does the progestogen component affect cardiovascular and clotting risk?
Yes. Women who still have a uterus generally need a progestogen alongside systemic oestrogen to protect the endometrium. The type of progestogen can influence the overall risk profile, and micronised progesterone or dydrogesterone may have a more favourable thrombotic profile than some other progestogens.
9. Is MHT safe for women with cardiovascular risk factors?
MHT is not automatically contraindicated simply because a woman has cardiovascular risk factors. The overall cardiovascular risk, age, time since menopause, blood pressure, smoking status, lipid profile, history of VTE or cardiovascular disease, and route and dose of MHT should all be considered. Transdermal oestrogen is often preferred when cardiovascular or thromboembolic risk is increased.
10. When is the benefit-risk balance of MHT most favourable?
For most healthy symptomatic women who are younger than 60 years or within 10 years of menopause, the benefits of MHT generally outweigh the risks when there are no contraindications. Treatment should be individualised, using the lowest effective dose appropriate for symptom control, with regular review. Starting MHT more than 10 years after menopause or after age 60 requires greater caution because the absolute risks of cardiovascular disease, stroke and VTE are higher.