The timing hypothesis
HRT is best started within 10 years of the onset of symptoms
During (peri)menopause, estrogen levels in your body decline. This doesn't just cause symptoms like hot flashes or sleep problems — your heart and blood vessels gradually change as well.
The decline in estrogen causes:
- fat to accumulate more easily around the abdomen
- cholesterol levels to rise
- insulin resistance to develop
- blood pressure to increase
Additionally, estrogen plays a protective role for the inner lining of your blood vessels, keeping them supple and healthy.
Why is timing so important?
The timing hypothesis explains that the effect of hormone replacement therapy (HRT) strongly depends on when you start it, relative to menopause.
Starting early: a protective effect
When HRT is started within 10 years of the onset of menopause:
- estrogen can maintain its protective effect on the blood vessels
- it helps slow down hardening of the arteries (atherosclerosis)
- it can reduce your long-term cardiovascular risk
In other words: estrogen can support your blood vessels as long as they are still healthy.
Starting late: more caution needed
When HRT is started much later:
- the blood vessels are often already partially damaged
- estrogen can make existing plaques in the vessel wall less stable
- the risk of thrombosis, heart attack, or stroke increases
In such a situation, a dislodged plaque can block a blood vessel, potentially causing permanent damage.
What if you've been in menopause for more than 10 years?
If you've been in menopause for more than 10 years, HRT is still possible. In that case, a risk analysis is first conducted (possibly with additional tests) and the best solution is sought together.
This information is intended solely for educational and informational purposes. It does not replace medical advice, diagnosis, or treatment by a physician or other qualified healthcare provider. Always consult your doctor if you have questions or concerns about your health or treatment.