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

OBJECTIVE

To examine the risk of poor child development according to week of gestation at birth, among children born ≥ 37 weeks' gestation.

DESIGN

Population-based study using linked data (n = 12,601).

SETTING

South Australia.

POPULATION

All births ≥ 37 weeks' gestation.

METHODS

Relative risks of developmental vulnerability for each week of gestation were calculated with adjustment for confounders and addressing missing information.

MAIN OUTCOME MEASURES

Child 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.

RESULTS

The percentage of children vulnerable on one or more AEDI domains for the following gestational ages 37, 38, 39, 40, 41, 42-45 weeks was 24.8, 22.3, 20.6, 20.0, 20.4 and 24.2, respectively. Compared with children born at 40 weeks, the adjusted relative risks [(95% confidence interval (CI)] for vulnerability on ≥ 1 AEDI domain were; 37 weeks 1.13 (0.99-1.28), 38 weeks 1.05 (0.96-1.15), 39 weeks 1.02 (0.94-1.12), 41 weeks 1.00 (0.90-1.11) and 42-45 weeks 1.20 (0.84-1.72).

CONCLUSIONS

Children born at 40-41 weeks' 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.