Risk of Developmental Disorders in Children Born at 32 to 38 Weeks' Gestation: A Meta-Analysis.

Context: Very preterm birth (<32 weeks) is associated with increased risk of developmental disorders. Emerging evidence suggests children born 32 to 38 weeks might also be at risk.

Objectives: To determine the relative risk and prevalence of being diagnosed with, or screening positive for, developmental disorders in children born moderately preterm, late preterm, and early term compared with term (≥37 weeks) or full term (39-40/41 weeks).

Data Sources: Medline, Embase, Psychinfo, Cumulative Index of Nursing, and Allied Health Literature.

Study Selection: Reported ≥1 developmental disorder, provided estimates for children born 32 to 38 weeks.

Data Extraction: A single reviewer extracted data; a 20% sample was second checked. Data were pooled using random-effects meta-analyses.

Results: Seventy six studies were included. Compared with term born children, there was increased risk of most developmental disorders, particularly in the moderately preterm group, but also in late preterm and early term groups: the relative risk of cerebral palsy was, for 32 to 33 weeks: 14.1 (95% confidence intervals [CI]: 12.3-16.0), 34 to 36 weeks: 3.52 (95% CI: 3.16-3.92) and 37 to 38 weeks: 1.44 (95% CI: 1.32-1.58).

Limitations: Studies assessed children at different ages using varied criteria. The majority were from economically developed countries. All were published in English. Data were variably sparse; subgroup comparisons were sometimes based on single studies.

Conclusions: Children born moderately preterm are at increased risk of being diagnosed with or screening positive for developmental disorders compared with term born children. This association is also demonstrated in late preterm and early term groups but effect sizes are smaller.