Around 1,000 of these children were born between 32 and 35 weeks of pregnancy and classified as ‘moderately premature’, and 600 were born at term.
The tests measured emotional problems including anxiety, depression and somatic complaints-conditions with no obvious physiological cause, and behavioural problems such as aggression and attention disorders.
Overall, boys - one in ten - were more likely to have behavioural problems, whereas more girls displayed emotional problems.
However, it was the ‘moderately premature’ children that scored highest on all the tests, with those children almost twice as likely to have behavioural and emotional problems and somatic complaints at the age of four.
Marieke Potijk from the Department of Health Sciences, Community and Occupational Medicine at the University Medical Centre, said, ‘Our results demonstrate that moderately premature children are more likely to already have behavioural and emotional problems before they start school.
‘These types of problems tend to persist into later childhood and adolescence and are likely to affect children’s academic performance and friendships at school.’
The authors go on to recommend that ‘moderately premature’ children should receive treatment for behavioural and emotional problems early to prevent problems persisting later on.
They also recommend that children born early are given extra support at school.
The study Higher rates of behavioural and emotional problems at preschool age in children born moderately preterm is published online in the journal Archives of Disease in Childhood.