They might be harder to catch – and no doubt leave their mothers more exhausted¹ – but children born to mums over 40 are healthier and brighter than those of younger women.

也许他们更难被怀上，无疑也会让他们的母亲更加精疲力竭，但是年过40的女性生出的小孩比年轻女性生出的小孩更健康、更聪明。

The offspring of older women are less likely to have accidents or need hospital care and more likely to have been vaccinated² early, a study found.

They will also develop a broader vocabulary from a young age and achieve higher scores in IQ tests in a range of measures up to the age of five.

The research, to be presented today at The Royal College of Paediatrics and Child Health conference in Glasgow, is a rare piece of good news for the rising number of women who are delaying motherhood.

Previous studies have highlighted the growing infertility³ rates for older women and the greater risk of them developing diabetes⁴ and pre-eclampsia.

But the latest research appears to show gains for older mothers once they have given birth, possibly due to their greater experience and maturity⁵.

The number of mothers who gave birth over the age of 40 increased from 15,000 in 2000 to 27,000 in 2010.

Researchers at the Institute of Child Health, University College London and Birkbeck College, London, said their findings showed older mothers can make better parents.

Dr Alastair Sutcliffe, who worked on the study, said negative publicity⁶ surrounding the rise of older mothers was based on the physical risks of pregnancy⁷ and childbirth.

He said: 'We have clear evidence that there are more desirable outcomes for children of older mothers compared with younger ages. We can reassure⁸ these older women that their children are probably better off.'

The Wellcome Foundation-funded study looked at 1,100 children born to women aged⁹ 40 and over, compared with 38,000 children born to younger women in Britain. The children's ages ranged from nine months to five years.

The research also checked a number of outcomes linked to parenting skills, including naming vocabulary, picture and shapes identification and developmental IQ using established British assessment¹⁰ scales. The findings showed greater ability among children born to older mothers once social class was taken into account.