Stress raises risk of having babies with behavioural problems

Published on Monday 29 June 2009 22:03

MOTHERS who are stressed during pregnancy could be at risk of giving birth to babies with a higher chance of learning difficulties and behavioural problems.

Scientists have found stress caused by violent or abusive relationships could have a particularly harmful effect on an unborn child and may have an adverse effect on the development of a baby's brain.

Professor Vivette Glover, from the Institute of Reproductive and Developmental Biology at Imperial College London, said: "We all know that if a mother smokes or drinks a lot of alcohol while pregnant it can affect her foetus.

"Our work has shown that other more subtle factors, such as her emotional state, can also have long-term effects on her child."

She added: "Our research shows that stress due to the mother's relationship with her partner can be particularly damaging."

The research team believe babies in the womb can be affected by the stress hormone cortisol. Normally the placenta acts as a barrier – but when a mother is stressed the placenta is less protective and the mother's cortisol may have an effect on the foetus.

A healthy placenta produces an enzyme which breaks down and neutralises the hormones coming from the mother's bloodstream.

However when a mother is under stress she loses her ability to produce this enzyme, which means her own stress hormones can pass into the body of her baby.

Professor Glover's team found a direct correlation between the amount of cortisol in the amniotic fluid and the development of the baby's cognitive ability.

The higher the level of cortisol in the amniotic fluid the lower the level of development at the age of 18 months.

Some previous studies have suggested maternal stress can lead to increased anxiety or depression and to behavioural problems such as Attention Deficity Hyperactivity Disorder (ADHD) and slow learning.

Other researchers have even suggested it might increase the likelihood of violent or criminal behaviour.

About a million children in the UK have neurodevelopmental problems such as ADHD , cognitive delay and anxiety.

Professor Glover and her team will be demonstrating their findings and suggesting ways expectant parents can minimise stress and anxiety at the Royal Society Summer Science Exhibition which opens in London today.

Visitors will be able to take part in a game that shows how a mother's stress can increase the heart rate of her unborn baby – in a display which the scientists hope will emphasise the importance of a happy and peaceful pregnancy.

Visitors to the exhibition will be able to see a real placenta encased in plastic, to understand the mechanism which protects a child in the womb and the way that barrier can break down.

Prof Glover said: "We want fathers visiting our exhibit to see how they can help with the development of their child even before the birth, by helping their partner to stay happy."

Dr Christine Puckering, a specialist in infant mental health from the University of Glasgow, said: "I think it is well established that stress in pregnancy has a long term effect on the baby's development and behaviour.

"If mothers are very stressed during pregnancy your baby is at a very high risk of developing behavioural problems.

"And women are particularly vulnerable during pregnancy. It is a high-risk time."