Childless women are a fifth less likely to suffer hot flushes during the menopause than those who have been pregnant, a study found.
Even if they do endure flushes, these are likely to be less frequent.
Meanwhile mothers diagnosed with high blood pressure, pre-eclampsia or diabetes during pregnancy were found to have greater risk of flushes than those with healthy gestations.
Researchers in the US questioned 2,249 women about their experience of hot flushes, which affect up to four in five females during the menopause and can last for years.
Those surveyed, who had an average age of 61, recorded the temperature fluctuations they suffered over a fortnight, from zero to on six or more days. The results showed women without children were 19 per cent less likely to have flushes compared to women who had been pregnant without complications.
Childless women who did feel suddenly hot were less likely to do so on six or more days.
Women diagnosed with gestational diabetes or disorders causing high blood pressure in pregnancy had a 19 per cent higher chance of hot flushes.
This may be due to problems with the lining of blood vessels, which cause both flushes and these pregnancy complications.
Dr Rhoda Conant from the University of Oklahoma Health Sciences Centre, who led the study, said: ‘This further underscores the importance of pregnancy complications such as gestational diabetes and pre-eclampsia for later health, particularly cardiovascular health at midlife.’
She added that there was a link between these complications and weight. ‘Women with a history of these pregnancy disorders were heavier and more likely to be taking lipid-lowering medications and diabetes medications,’ she said.
Kathy Abernethy, from the British Menopause Society, said: ‘Research is beginning to show that hot flushes and night sweats in menopause might be a marker or “warning sign” for cardiovascular risk.
‘The same women at risk of heart problems who have these hot flushes may in some cases have complications in pregnancy such as pre-eclampsia and gestational diabetes.
‘We do know however that even women who may not be at risk of heart problems do get flushes too, so we still need more research.’
It is unclear why women who have never had a baby may suffer less with hot flushes, although previous studies have found the same result.
The research, presented at the annual meeting of the North American Menopause Society, found that women’s education may be a factor in explaining the results, though it was unclear why. However highly educated women are known to be less likely to have children.
Dr JoAnn Pinkerton, executive of NAMS, said: ‘With so many women affected by hot flushes, healthcare providers need to understand all the underlying risk factors that could influence them.’