Why winter babies have learning difficulties

BABIES conceived in winter are more likely to develop learning difficulties, a major Scottish study suggests.

Scientists think lack of exposure to sunlight in the early stages of pregnancy may affect brain development.

A study of more than 800,000 schoolchildren in Scotland found 8.9 per cent of those conceived in January to March had learning disabilities, compared to 7.6 per cent of those conceived between July and September.

One in five people in Britain has low levels of vitamin D, which is produced by the skin when it soaks up the sun’s rays. It is particularly important in pregnancy and is known to affect the way a baby’s bones grow in the womb.

But the new study, led by experts at Glasgow University, suggests it also has a profound impact on brain development.

Carried out in collaboration with Cambridge University, the NHS and the Scottish Government, it found winter babies were more likely to develop autism, intellectual difficulties and learning problems such as dyslexia.

There were no patterns for other causes of learning difficulties, such as visual or hearing problems or physical illness.

The children in the research were born before 2012 guidelines advising all pregnant women to take vitamin D supplements.

Professor Gordon Smith, head of obstetrics and gynaecology at Cambridge University, said: ‘If vitamin D levels explain the seasonal fluctuations observed in this study, we would hope that widespread compliance with the advice would lead to loss of this variation and would have a downward effect on overall rates of special educational needs.

‘Although the current study did not directly measure vitamin D, it remains perhaps the most plausible explanation for the trend.’

Professor Jill Pell, director of Glasgow University’s Institute of Health and Wellbeing, said: ‘It is important pregnant women follow the advice.’

The research was published in the American Journal of Epidemiology.