The purpose of this study is to test the feasibility of measuring body composition by air displacement plethysmography (ADP) in rapidly growing, medically stable late gestation [32-35 weeks post-menstrual age (PMA)] premature infants.

1. To assess the feasibility of measuring body fat deposition by ADP in medically stable late gestation (32-35 weeks), premature infants during a period of rapid postnatal growth.
2. To test the relationship between %BF by ADP to %BF by DXA, as well as characterize the relationship between these fat measures with bone measures by quantitative ultrasound and serum levels of insulin, IGF-1, IGF binding proteins, adiponectin and leptin.
3. To perform inter- and intra-rater testing of anthropometric, ultrasound, and ADP measurements.
4. Compare growth, body composition and bone strength between infants born preterm to infants born full term.

Inclusion Criteria:

• Infants born between 32 4/7 and 35 3/7 weeks gestation or 37 4/7 and 42 3/7 weeks gestation, by physical exam at birth
• Birth weight between the 5th and 95th percentile corrected for gestational age

Exclusion Criteria:

• Chromosomal abnormalities
• Major congenital anomalies
• Major surgery
• Severe CNS injury
• Inborn errors of metabolism
• Assisted ventilation
• Inability to start enteral feeds by 96 hours of age

Premature and full term infants admitted to the University of Utah Newborn Intensive Care Unit, Intermediate Nursery or Well Baby Nursery