Babies born severely prematurely or underweight are likely to suffer in adulthood with a socially withdrawn personality, new research has shown.
Around 12% of babies in the UK are born prematurely each year, and 1-2% are severely premature, being born before 32 weeks. With around 700,000 UK births each year, this equates to a significant number of premature babies.
It is well known that premature birth causes babies to suffer many problems in later life, including learning disabilities and lower IQ.
Now, for the first time, Professor Dieter Wolke and colleagues from the University of Warwick have studied the effect of premature birth on the personalities of the children as they have grown up. Very often, the team have found, these infants go on to develop what has been dubbed a "socially withdrawn personality".
Wolke's work shows that adults who had been born prematurely are more likely to display a range of personality disorders in later life. These include increased anxiety and neuroticism, decreased risk-taking, and more autistic features, such as difficulty making conversation.
This could explain the difficulties often experienced by these adults in their career paths and interpersonal relationships. These adults are less likely to reach well-paid jobs, and have more difficulty in establishing friendships and partners.
In this study, Wolke followed a large number of children born in southern Germany from birth until age 26. 200 of these were born very pre-term or severely underweight, and 197 were born normally.
At age 26 these adults were interviewed to determine their personality traits in 5 main areas: introversion, conscientiousness, agreeableness, neuroticism (anxiety) and risk taking, including willingness to experience new things.
It was found that adults that had been born prematurely were more introverted and neurotic than those born at term. They were also less conscientious and agreeable, and took fewer risks. The results were independent of gender, socioeconomic status and IQ.
There are a number of possible reasons for these affects on personality. It is likely to be linked to changes in the structure of the brain caused by premature birth and neonatal care. When a baby is born severely prematurely, "its organs are asked to do functions they wouldn’t normally do [at such an early stage], such as breathing," says Wolke. This has a structural effect on the brain, resulting in less folding of the cortex to form the characteristic "walnut shape".
There can be other causes too. Premature babies have to spend a significant amount of time in intensive care in hospital before they can come home. During this time, they are often kept in incubators and the parents are unable to take them out to cuddle. The babies often need to be fed via a naso-gastric tube or sometimes even via the bloodstream, and they require help breathing. These necessitate the use of tubes inserted into the babies via their hands or mouth and can be a major source of stress for the newborn.
This is also a very stressful time for the parents, says Wolke. This "may cause them to be more overprotective" of their child as it grows up, compounding any personality problems.
Having a withdrawn personality can mean that these children are quieter and more reserved at school, which can lead to them being overlooked by their teachers. They are also more likely to be bullied which sets up a vicious circle, causing the children to become even more withdrawn.
But what can we do about this? According to Wolke, parents of premature children should ensure that they have friends coming round to enable social relationships to be built up. Teachers should also be aware of these children so they can watch out for social exclusion and put a stop to bullying...