A systematic review and meta-analysis of long-term development of early term infants

Background: Births between 37 0/7 and 38 6/7 weeks of gestation are newly defined as early term infants (ETIs), and are increasingly considered to be at higher risk of adverse outcomes than infants born at 39-41 weeks' gestation. To date, the long-term development of ETIs has not been systematically reviewed.

Objective: To assess the effect of being born early term on long-term developmental outcomes.

Methods: The literature of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials, and abstracts from the Society of Pediatric Research were searched. If two or more studies regarding the same outcome were retrieved, a meta-analysis was conducted by RevMan 5. A sensitivity analysis was performed to assess the heterogeneity.

Results: Eleven studies involving 4 categories of long-term development were included. Compared with infants born at 39-41 weeks' gestation, ETIs had poorer outcomes in school performance, neurodevelopment, behavior and emotional status and long-term social outcomes. Meta-analyses showed that being born early term significantly increased the risk of cerebral palsy [relative risk, RR, 1.75 (95% confidence interval, CI, 1.32, 2.31)] and mathematical difficulties [RR 1.13 (95% CI 1.04, 1.21)]. The statistical test of heterogeneity for cerebral palsy was significant. Sensitivity analysis demonstrated that variations in follow-up periods were associated with heterogeneity.

Conclusion: Emerging evidence suggests that ETIs are at risk of adverse long-term outcomes. Due to paucity and heterogeneity of the existing data, future research is needed to clarify the long-term risk of being born early term.