364 Body Composition in Small for Gestational and Large for Gestational Age Infants at One Week and 12 Weeks of Age

Abstract

Background: Full term infants born small for gestational age (SGA) or large for gestational age (LGA) are at an increased risk for metabolic complication. Improved nutrition with catch-up growth has been related to insulin resistant and metabolic syndrome leading to the concern that “bigger might not be better”. Aims: To use Pea Pad, a device based on air displacement plethysomgraphy, to compare body composition in full-term infants born SGA and LGA. Methods: Body composition was assessed in 20 infants born SGA and in 20 infants born LGA in the first week of life and at 12 weeks. Results: At one week SGA infants contained 3,9 (± 2,0) % body fat and LGA infants contained 16,3 (± 5,2) % body fat. At 12 weeks SGA infants body weight were 6071 (± 675) g and contained 26 (± 4,1) % body fat. LGA infants body weight were 7205 (±792) g and contained 27,3 (± 5,0) % body fat. There was a significant difference in body weight, but no significant difference in % body fat (p= 0,59) between the groups at 12 weeks. The regression line between body fat (dependent variable) and body weight was for SGA infants at 12 weeks y=4,46 + 0,04 x, r=0,58, p=0,003 and for LGA infants y=20,9 + 0,001 x, r=0,14, p=0,6. Conclusions: The catch up growth in SGA infants consist of “catch up fat” compared to LGA infants. It seems that LGA infants sustained a metabolic capacity and SGA developed a metabolic load at 12 weeks.