A whole-of-population study of term and post-term gestational age at birth and children's development

ObjectiveTo examine the risk of poor child development according to week of gestation at birth, among children born 37weeks' gestation. DesignPopulation-based study using linked data (n=12601). SettingSouth Australia. PopulationAll births 37weeks' gestation. MethodsRelative risks of developmental vulnerability for each week of gestation were calculated with adjustment for confounders and addressing missing information. Main outcome measuresChild development was documented by teachers during a national census of children attending their first year of school in 2009, using the Australian Early Development Index (AEDI). Children scoring in the lowest 10% of the AEDI were categorised as developmentally vulnerable. ResultsThe percentage of children vulnerable on one or more AEDI domains for the following gestational ages 37, 38, 39, 40, 41, 42-45weeks was 24.8, 22.3, 20.6, 20.0, 20.4 and 24.2, respectively. Compared with children born at 40weeks, the adjusted relative risks [(95% confidence interval (CI)] for vulnerability on 1 AEDI domain were; 37weeks 1.13 (0.99-1.28), 38weeks 1.05 (0.96-1.15), 39weeks 1.02 (0.94-1.12), 41weeks 1.00 (0.90-1.11) and 42-45weeks 1.20 (0.84-1.72). ConclusionsChildren born at 40-41weeks' gestation may have the lowest risk of developmental vulnerability at school entry, reinforcing the importance of term birth in perinatal care. Early term or post-term gestational age at birth can help clinicians, teachers and parents recognise children with potential developmental vulnerabilities at school entry.