The purpose of this study is to gain information that may be useful in helping to figure out better or newer ways to provide nutrition to babies born premature.

Babies born premature weigh significantly less at the time of hospital discharge when compared to babies born at the corresponding age. The researchers in this study believe that the lower body weight at discharge may be due to lower muscle mass. However, there is no such information available for that at this time. It is important to have this information as babies who weigh less than normal at hospital discharge may develop higher blood pressure and higher sugar levels when they are 10-15 years old.

By doing this study, researchers will be able to have information about the baby's muscle mass, which will help the researchers to provide better nutrition to babies who are born premature. Researchers will also be able to determine if there are any differences in the muscle/fat mass based on the type of feeding (breast milk alone, formula alone or a combination of breast milk and formula). This information may be beneficial in helping to promote the appropriate type of feeding for babies born premature.

Inclusion Criteria:

• Newborns <32 weeks gestational age, singleton or multiple gestation
• 34-36 weeks gestational age newborns
• Term healthy infants from uncomplicated pregnancy

Exclusion Criteria:

• Babies with life threatening illness unlikely to survive
• Congenital and chromosomal anomalies

The study group involves premature infants born between 23 to 32 weeks gestation, while babies born at 34 weeks, 36 weeks and ≥37 and ≤ 42 weeks gestational age will serve as control groups.