Preterm birth, age at school entry and educational performance

Abstract

Objective: To investigate if the lack of gestational age correction may explain some of the school failure seen in ex-preterm infants.

Design: A cohort study based on the Avon Longitudinal Study of Parents and Children (ALSPAC). The primary outcome was a low Key Stage 1 score (KS1) score at age 7 or having special educational needs (SEN). Exposure groups were defined as preterm (<37 weeks gestation, n = 722) or term (37-42 weeks, n = 11,268). Conditional regression models were derived, matching preterm to term infants on date of birth (DOB), expected date of delivery (EDD) or expected date of delivery and year of school entry. Multiple imputation was used to account for missing covariate data.

Results: When matching for DOB, infants born preterm had an increased odds of a low KS1 score (OR 1.73 (1.45-2.06)) and this association persisted after adjusting for potential confounders (OR 1.57 (1.25-1.97)). The association persisted in the analysis matching for EDD (fully adjusted OR 1.53 (1.21-1.94)) but attenuated substantially after additionally restricting to those infants who entered school at the same time as the control infants (fully adjusted OR 1.25 (0.98-1.60)). A compatible reduction in the population attributable risk fraction was seen from 4.60% to 2.12%, and year of school entry appeared to modify the association between gestational age and the risk of a poor KS1 score (p = 0.029).

Conclusions: This study provides evidence that the school year placement and assessment of ex-preterm infants based on their actual birthday (rather than their EDD) may increase their risk of learning difficulties with corresponding school failure.

Figure 1. Mean Key Stage 1 scores by gestation and month of birth.