Newborn Adiposity Measured by Plethysmography Is Not Predicted by Late Gestation Two-Dimensional Ultrasound Measures of Fetal Growth ,

Abstract

Noninvasive measures of fetal and neonatal body composition may provide early identification of children at risk for obesity. Air displacement plethysmography provides a safe, precise measure of adiposity and has recently been validated in infants. Therefore, we explored relationships between term newborn percent body fat (%BF) measured by air displacement plethysmography to 2-dimensional ultrasound (2-D US) biometric measures of fetal growth and maternal and umbilical cord endocrine activity. A total of 47 mother/infant pairs were studied. Fetal biometrics by 2-D US and maternal blood samples were collected during late gestation (35 wk postmenstrual age); infants were measured within 72 h of birth. Fetal biometrics included biparietal diameter, femur length, head circumference, abdominal circumference (AC), and estimated fetal weight (EFW). Serum insulin, insulin-like growth factor (IGF) 1, IGF binding protein-3, and leptin concentrations were measured in umbilical cord and maternal serum. The mean %BF determined by plethysmography was 10.9 +/- 4.8%. EFW and fetal AC had the largest correlations with newborn %BF (R(2) = 0.14 and 0.10, respectively; P < 0.05); however, stepwise linear regression modeling did not identify any fetal biometric parameters as a significant predictor of newborn %BF. Newborn mid-thigh circumference (MTC; cm) and ponderal index (PI; weight, kg/length, cm(3)) explained 21.8 and 14.4% of the variability in %BF, respectively, and gave the best stepwise linear regression model (%BF = 0.446 MTC + 0.347 PI -29.692; P < 0.001). We conclude that fetal growth biometrics determined by 2-D US do not provide a reliable assessment of %BF in term infants.

Fetal growth pathology score: a novel ultrasound parameter for individualized assessment of third trimester growth abnormalities

“…Soft tissue abnormalities are frequently seen in growth restricted SGA neonates [7]. Weight measurements may not accurately reflect soft tissue development since GR can occur without weight abnormalities [7,19] and weight does not strongly correlate with percent body fat [20,21]. The incidence of weight abnormalities (52.9%) was substantially lower than that for thigh circumference (76.5%) in growth restricted SGA neonates [7].…”

Novel noninvasive anthropometric measure in preterm and full-term infants: normative values for waist circumference:length ratio at birth

“…Articles plethysmography (11,36). Newborn data for PI are available for Chinese and German infants, but data in the United States are limited, especially for infants born preterm (11,37).…”

Impact of Maternal Obesity on Fetal Health

“…IGF-1:IGFBP3 ratio and leptin levels are higher in cord blood of large-for-date fetuses. Higher IGF-1:IGFBP3 ratio may indicate a greater amount of unbound IGF-1 causing increased fetal growth [26]. These are some examples for processes which act in league to cause a net increase in available energy and ‘building blocks' to the fetus and this combined with the hyperinsulinemic state may explain the increase in large-for-gestational-age infants seen in obese women.…”

“…Serum concentrations of leptin are positively associated with body fat stores [24]. Maternal obesity is accompanied by maternal hyperleptinemia and placental leptin resistance contributing to alternations in placental function and amino acid transfer [25].…”