The role of parental education on the relationship between gestational age and school outcomes

Background Individuals born preterm may experience difficulties beyond the neonatal period, such as poorer school outcomes. However, whether these outcomes are modified by family factors is less well-known. Objectives To investigate whether parental educational level modify the relationship of gestational age with completion of final examinations and grade point average in compulsory education. Methods This nationwide register-based cohort study included singletons born in Denmark during 1995-2001. We investigated the differences in the associations between gestational age (24-44 weeks) and two school outcomes at 16 years according to parental educational level (lower (<= 10 years), intermediate (11-13 years), and higher (>13 years)). Mixed-effect logistic regression and mixed-effect linear regression were used to model completion of final examination and grade point average, respectively. Results Of the 425 101 singletons, 4.7% were born before 37 weeks. The risk of not completing final examination increased with shorter gestational age and lower parental educational level. For instance, among adolescents whose parents had a lower educational level, the risk increased from 23.9% (95% CI, 23.1, 24.6) for those born in week 40 to 36.6% (95% CI, 31.5, 42.1) for those born in week 28. For adolescents whose parents had a higher educational level, the corresponding risk increase was 5.9% (95% CI, 5.7, 6.1) to 10.5% (95% CI, 8.6, 12.8), respectively. Grade point average decreased with shorter gestational age in adolescents born before 30 weeks and with lower parental educational level. The associations between gestational age and grade point average were similar across parental educational levels. For completions of final examination, the associations with gestational age were weaker with higher parental educational level. Conclusions Shorter gestational age and lower parental educational level were associated with poorer school outcomes. Our findings suggest that parental educational level mitigates the adverse effects of shorter gestational age on some school outcomes.