Head Circumference within the Normal Range and Neurodevelopmental Outcomes in Preterm Infants

Area of Science:

• Perinatology
• Neurodevelopmental Pediatrics
• Biostatistics

Background:

• Head circumference (HC) is a key indicator of fetal growth and brain development.
• Understanding the relationship between HC variations and neurodevelopmental outcomes (NDO) is crucial for early identification of potential issues.
• Previous research has not conclusively determined if HC variations within the normal range are associated with adverse NDO.

Purpose of the Study:

• To investigate the association between variations in head circumference (HC) within the normal range (5th-95th percentile) and neurodevelopmental outcomes (NDO) at age two.
• To determine if small-normal (5th-10th percentile) or large-normal (90th-95th percentile) HC is linked to poor neurodevelopmental outcomes.
• To assess the impact of a continuous change in HC (per 1 cm) on NDO.

Main Methods:

• Secondary analysis of a randomized controlled trial on magnesium for cerebral palsy prevention.
• Included fetuses with normal HC (5th-95th percentile) at birth.
• NDO assessed at age two using Bayley II psychometrics (BSID-II); mild delay (<85), moderate delay (<70).
• HC categorized as small normal (5th-10th), normal (10th-90th), and large normal (90th-95th).
• Logistic and linear regression models used for analysis, adjusting for confounders.

Main Results:

• 1,236 infants included: 8% small normal HC, 85% normal HC, 5% large normal HC.
• No significant association found between HC variations (small normal, large normal) and developmental indices.
• Continuous analysis showed no significant change in developmental indices for every 1 cm increase in HC.
• Baseline characteristics were similar across HC groups.

Conclusions:

• Variations in head circumference within the normal range (5th-95th percentile) are not associated with poor neurodevelopmental outcomes at two years of age.
• Changes in HC within the normal range do not appear to be a pathological factor affecting neurodevelopmental outcomes.
• A 1 cm increase in HC, when considered continuously, does not correlate with adverse neurodevelopmental outcomes.