Small Size at Birth or Abnormal Intrauterine Growth Trajectory: Which Matters More for Child Growth?

Area of Science:

• Pediatrics
• Human Growth and Development
• Prenatal Medicine

Background:

• Small size at birth is associated with long-term health issues, but is a proxy for intrauterine growth restriction (IUGR).
• Understanding fetal growth patterns is crucial for assessing developmental trajectories and long-term health outcomes.

Purpose of the Study:

• To determine if intrauterine growth patterns enhance the prediction of childhood anthropometry beyond birth weight.
• To investigate the predictive value of conditional fetal growth z-scores and their residuals on anthropometric measures at age five.

Main Methods:

• Utilized serial ultrasound data to estimate fetal weights in 478 children from the Scandinavian Successive Small-for-Gestational-Age Births Study.
• Classified birth size using birth weight-for-gestational-age z-scores and conditional fetal growth z-scores (25 weeks' gestation to birth).
• Employed linear regression to link growth measures with anthropometric characteristics at age five.

Main Results:

• Conditional fetal growth z-scores showed positive associations with child height, BMI, skinfold thickness, and head circumference in univariable analyses.
• Conditional fetal growth z-scores were highly correlated with birth weight z-scores (r=0.9).
• Residuals of conditional z-scores explained minimal additional variation in anthropometric factors, with adjusted R-squared increases less than 0.01.

Conclusions:

• Information on the intrauterine growth trajectory provides little additional insight into childhood anthropometry compared to absolute birth size.
• Birth weight alone is a sufficient predictor for childhood anthropometric outcomes in this cohort.
• Focusing solely on birth weight may adequately capture developmental information relevant to childhood growth.