Results
Table 1 compares demographic and birth characteristics of 5145 children of whom 4537 (88.2%) were born at term, 382 were born post-term (7.4%) and 226 were born preterm (4.4%).
In Figure 1, the unadjusted associations between the Total Problems scale and GA at age 18 and 36 months are shown. The curves show a nadir of the Total Problems score in children born with a GA around 40 weeks, whereas the mean problem scores are higher in children who are born more preterm or more post-term. In addition, we present a scatterplot of the correlation between GA at birth and Total Problems score in theSupplementary data, available at IJE online.