Objective To determine the occurrence of emotional and behavioural problems (EBP) in moderate to late preterm (MLP) and full-term children with developmental delay.

Design Participants were recruited from 13 randomly selected preventive child healthcare (PCH) centres in the Netherlands. We included 903 MLP children of 32–36 weeks’ gestation and 538 full-term controls, born between January 2002 and June 2003. Parents completed the Ages and Stages Questionnaire (ASQ) and Child Behaviour Checklist (CBCL) shortly before the scheduled PCH visit at 4 years of age. Co-occurrence was defined as: ASQ total or domain score >2 SDs below the mean and a CBCL score >84th percentile on total problems, internalising (emotional) or externalising (behavioural) problems.

Results EBP were more prevalent among MLP children with abnormal ASQ total problems scores than among full-term children, particularly regarding externalising problems (33.8% vs 23.8%). In MLP children, rates of EBP differed per developmental domain and were highest for the domains problem-solving (36.0% had externalising problems, 95% CI 24.1% to 49.9%) and personal-social skills (38.7% had internalising problems, 95% CI 26.4% to 52.8%). The risk of any type of co-occurrence was higher for MLP than for full-term children (OR 1.86; 95% CI 1.14 to 3.03). Independent risk factors for co-occurrence were male gender, low socioeconomic status and young maternal age.

Conclusions Up to 39% of 4-year-old MLP children with developmental delay also have EBP, indicating that increased awareness of EBP is warranted in MLP children with developmental delay. Further research is needed to determine whether early detection of co-occurring problems results in better long-term health.