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Risk of Developmental Disorders in Children Born at 32 to 38 Weeks' Gestation: A Meta-Analysis
Katherine J Pettinger1, Clare Copper2, Elaine Boyle3
1University of York, York, United Kingdom.
Insights
Children born moderately preterm (32-36 weeks) face higher risks of developmental disorders. Even late preterm and early term births show increased risks compared to full term births.
Area of Science:
- Neonatal development
- Pediatric neurology
- Public health
Background:
- Very preterm birth (<32 weeks) is a known risk factor for developmental disorders.
- Emerging evidence suggests potential risks for infants born between 32 and 38 weeks gestation.
Approach:
- Systematic review and meta-analysis of 76 studies.
- Data extracted from Medline, Embase, Psychinfo, and CINAHL.
- Pooled estimates using random-effects models to assess relative risk.
Key Points:
- Moderate preterm birth (32-36 weeks) significantly increases the risk of developmental disorders.
- Late preterm (37 weeks) and early term (37-38 weeks) births also show elevated risks, though with smaller effect sizes.
- Cerebral palsy risk was notably higher in moderately preterm infants (RR 14.1 for 32-33 weeks) compared to term infants.
Conclusions:
- Infants born moderately preterm are at a substantially increased risk for developmental disorders.
- Late preterm and early term births are associated with a smaller, yet significant, increased risk.
- Further research is needed to understand the long-term implications across diverse populations.
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.
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