Women who go into early menopause or do not use hormone replacement therapy could be at a higher risk of stroke, a study found.
Those with longer reproductive lifespans and who used contraceptives or HRT had fewer strokes by their mid-60s.
Experts said the findings suggest those who start menopause early should be offered more regular blood pressure and cholesterol checks.
Researchers used data from almost 123,000 postmenopausal women, with an average age of 58.
They were asked about their lifestyle as well as reproductive health information, number of pregnancies and oral contraceptive use.
Those with longer reproductive lifespans and who used contraceptives or HRT had fewer strokes by their mid-60s
Researchers then used health insurance and disease registry data to determine that 15,139 participants had a stroke in the following decade.
They were then divided into groups determined by their reproductive life span – the number of years from first menstruation to menopause.
This ranged from 31 years to 36. When researchers adjusted for other factors that could affect stroke risk, such as age, smoking, physical activity and high blood pressure, they found participants in the longest group had a 5 per cent lower risk of all kinds of stroke.
This rose to 13 per cent with intracerebral haemorrhage (bleeding on the brain) when compared to the shortest group, according to the findings published in the Neurology journal.
The Chinese researchers also looked at other factors affecting oestrogen levels, such as number of births and use of oral contraceptives.
They found that higher oestrogen levels led to a lower risk of all types of stroke.
Lead author Peige Song, of Zhejiang University in Hangzhou, said: ‘These findings might help with new ideas for stroke prevention, such as considering screenings for people who have a short lifetime exposure to oestrogen.’
