Neurodevelopmental outcomes at age 3 years after moderate preterm, late preterm and early term birth: the Japan Environment and Children's Study.

Objective: To assess the association between gestational age classification at birth and the risk of neurodevelopmental impairments at age 3 years.

Design: Cohort study using the Japan Environment and Children's Study database.

Patients: A total of 86 138 singleton children born without physical abnormalities at 32-41 weeks of gestation enrolled between January 2011 and March 2014.

Main Outcome Measures: Neurodevelopmental impairment, evaluated using the Ages and Stages Questionnaire (third edition).

Methods: Logistic regression analysis was used to evaluate the risk of neurodevelopmental impairment in moderate preterm, late preterm and early term children compared with term children after adjusting for socioeconomic and perinatal factors.

Results: The respective adjusted ORs (95% CIs) of incidence of scores below the cut-off value (<-2.0 SD) at age 3 years for moderate preterm, late preterm and early term births, compared with full-term births, were as follows: communication, 2.40 (1.54 to 3.73), 1.43 (1.19 to 1.72) and 1.11 (1.01 to 1.21); gross motor, 2.55 (1.69 to 3.85), 1.62 (1.36 to 1.93) and 1.20 (1.10 to 1.30); fine motor, 1.93 (1.34 to 2.78), 1.55 (1.35 to 1.77) and 1.08 (1.01 to 1.15); problem solving, 1.80 (1.22 to 2.68), 1.36 (1.19 to 1.56) and 1.07 (1.00 to 1.14) and personal-social, 2.09 (1.29 to 3.40), 1.32 (1.07 to 1.63) and 1.00 (0.91 to 1.11).

Conclusion: Moderate preterm, late preterm and early term births were associated with developmental impairment at age 3 years compared with full-term births, with increasing prematurity. Careful follow-up of non-full-term children by paediatricians and other healthcare providers is necessary for early detection of neurodevelopmental impairment and implementation of available intervention.