From the Guidelines
Being born at 38 weeks versus 40 weeks is unlikely to significantly affect a child's personality and behavior. Both 38 and 40 weeks are considered full-term births, with 40 weeks being the average pregnancy duration. While those final two weeks do allow for some additional brain development, research has not demonstrated meaningful differences in personality traits or behavioral outcomes between babies born at these gestational ages. The development of personality and behavior is influenced by a complex interplay of genetic factors, parenting styles, environmental exposures, and life experiences that occur after birth. These post-birth factors typically have a much stronger impact on personality formation than the difference between 38 and 40 weeks of gestation. Some subtle neurodevelopmental differences might exist, but they're generally not significant enough to noticeably shape personality in ways that would distinguish a child born at 38 weeks from one born at 40 weeks.
According to a study by the American Heart Association 1, premature infants, especially those born weighing 1500 g, are at increased risk for developmental delay. However, this study primarily focuses on infants born before 37 weeks, and its findings may not be directly applicable to infants born at 38 weeks. The study does suggest that lower birth weight and gestational age are associated with developmental delay in the complex CHD population, but it does not provide evidence of significant personality or behavioral differences between children born at 38 weeks and those born at 40 weeks.
Key points to consider:
- Both 38 and 40 weeks are considered full-term births
- The difference in brain development between 38 and 40 weeks may not be significant enough to impact personality or behavior
- Post-birth factors, such as parenting styles and environmental exposures, have a stronger impact on personality formation than gestational age
- Parents should focus on providing a nurturing environment after birth rather than concerning themselves with small differences in gestational age at delivery.
From the Research
Gestational Age and Developmental Disorders
- Being born at 38 weeks vs 40 weeks may affect the risk of developmental disorders, with children born at 38 weeks having a higher risk compared to those born at 40 weeks 2.
- The relative risk of cerebral palsy is 1.44 (95% CI: 1.32-1.58) for children born at 37-38 weeks, compared to those born at term (≥37 weeks) or full term (39-40/41 weeks) 2.
Gestational Age and Child Development
- Planned birth before 39 weeks is associated with an elevated risk of poor child development at school age, with the risk increasing with decreasing gestational age 3.
- The adjusted relative risk (aRR) of being developmentally high risk increases with decreasing gestational age, with an aRR of 1.06 (1.01-1.10) at 38 weeks and 1.17 (1.10-1.25) at 37 weeks 3.
Intervention Programs for Preterm Infants
- Therapist-led, parent-administered therapy and massage programs may support parent mental health and infant development, with high parent-rated feasibility and acceptability scores 4.
- Participation in early intervention (EI) therapy may be associated with more optimal cognitive function trajectories, particularly among preterm children whose mothers have more supports 5.
Community Supports for Preterm Infants
- Extremely preterm infants often require special outpatient services (SOS), with 54.7% using more than 3 SOS by 18-22 months and 19.1% using 6-7 SOS 6.
- The need for SOS is common even among preterm infants with mild developmental impairment or cerebral palsy, highlighting the importance of comprehensive community-based services 6.