Can extrauterine growth approximate intrauterine growth? Should it?

Area of Science:

• Neonatal research
• Pediatric growth assessment

Background:

• Current preterm infant growth evaluation relies on intrauterine growth curves and reference fetuses.
• These standards have limitations including small sample sizes, uncertain gestational age, and varying reasons for preterm birth or infant death.
• Postnatal preterm infants differ significantly from fetuses in environment and nutrition, making direct comparison problematic.

Purpose of the Study:

• To critically reevaluate the use of intrauterine growth curves for assessing preterm infant postnatal growth.
• To highlight the limitations of current standards and suggest the need for revised evaluation methods.

Main Methods:

• Review of existing literature on preterm infant growth and growth curve methodologies.
• Analysis of the biological and environmental differences between fetal and postnatal preterm infants.
• Examination of the implications of catch-up growth on neurodevelopment and long-term health outcomes.

Main Results:

• Intrauterine growth curves may not accurately reflect optimal growth trajectories for preterm infants in a postnatal environment.
• Catch-up growth, often pursued to meet intrauterine standards, may have mixed benefits, potentially aiding brain development but increasing later cardiovascular disease risk.
• Body composition, such as higher fat percentage, might be an adaptive response in preterm infants.

Conclusions:

• The reliance on intrauterine growth curves for preterm infant growth assessment requires critical reevaluation.
• Alternative or adjusted standards may be necessary to accurately evaluate the growth and development of preterm infants.
• The long-term consequences of catch-up growth strategies warrant further investigation.