Children are at double the risk of displaying symptoms of attention deficit hyperactivity disorder if their mother was overweight or obese when she became pregnant, according to European research.

It confirms for the first time in a large-scale study a suspected link between mothers' weight and children's mental health.

The study of nearly 2000 Swedish children identified a reduced ability to pay attention at school or preschool among those whose mothers had been overweight. This was even after taking into account the possible effects of mothers' mental health - which could influence the children's upbringing - and the children's own weight.

Children of obese mothers were also twice as likely to express negative emotions such as sadness and fear, and to have difficulty dealing with these appropriately, according to the research by Alina Rodriguez, a psychologist from the University of Uppsala. Her study followed the health of children from the first weeks of their mother's pregnancy through to age five.

Dr Rodriguez said a possible explanation was that excess weight might disrupt mothers' metabolism, making it harder for nutrients essential to brain development to reach the foetus.

Pregnancy puts huge stress on the metabolism, she said, and excessive weight gain might throw it out of balance - perhaps by raising mothers' levels of blood glucose, or of the hormone leptin.

Alternatively, the findings might result from inadequate vitamin D - which is linked to mental development and is known to be present in lower levels in overweight women - or from greater exposure to damaging chemicals, which accumulate in body fat.

Dr Rodriguez said her results, published in the Journal of Child Psychology and Psychiatry, could not prove whether maternal obesity caused the problems.

Source
PregnancyWeekly.com