This is a two stage open-label, single-arm, multicenter and observational study.

Stage 1: In hospital, preterm/low birth weight infants less than or equal to 34 weeks gestational age at birth, birth weight of ≥ 1000g to <1800g and conditions meeting the enrollment criteria will be fed formula with or without parenteral nutrition until discharge. Stage 2: Post-discharge, all infants with birth weight < or =1500g will be followed on formula per standard of care and accepted standard of care including feeding until the infant's weight >or= 25th percentile of growth expectation based on corrected age (P25) or until infant reaches 9 months corrected age.

Inclusion Criteria for Stage 1:

• Less than or equal to 34 weeks gestational age at birth, and birth weight ≥ 1000g to < 1800g;
• Apgar score in 5 minutes after birth ≥ 7;
• Infant is 21 days or less of age at enrollment;
• Only singleton or twin births;
• Infants who can receive early enteral feeding stably (reaching 50% or higher of the required daily total calories) and whose parents/guardians and investigators have selected Similac Special Care (SSC) for feeding;
• Infant has been classified as appropriate for gestational age (AGA) or if classified as asymmetric small for gestational age (SGA) (Asymmetric SGA: Weight below the 10th percentile, but head circumference is greater than or equal to the 10th percentile) enrollment has been preapproved by sponsor;

Inclusion Criteria for Stage 2:

• Infants with birth weight < or = 1500g, subjects whose parents/guardians and investigators have selected NeoSure for continued feeding after hospital discharge.

Exclusion Criteria for Stage 1:

• Serious congenital chromosomal or metabolic abnormalities that may affect growth and development;
• Congenital gastrointestinal malformations , including but not limited to congenital megacolon or gastric-intestinal perforation;
• Serious complications associated with preterm birth, including but not limited to necrotizing enterocolitis (NEC), septicemia or sepsis;
• Other serious disorders of cardiac/respiratory/endocrine/hematological/ gastrointestinal/other systems, or serious diseases requiring surgical intervention;
• Maternal incapacity: including maternal drug, cocaine or alcohol abuse during pregnancy or current;
• Infants who received any experimental treatment, participated in other clinical trials or received other study interventions unrelated to this study within 30 days prior to enrollment;
• Infants who have received or planned to receive breastfeeding or other infant formula (powder) other than SSC with calories intake ≥25% of the required daily total calories
• Intubation for ventilation at the time of enrollment.

Exclusion Criteria for Stage 2:

• Infants who have received breastfeeding or other infant formula (powder) during hospitalization other than SSC with calories intake ≥25% of the required daily total calories
• Infants who have planned to receive breastfeeding or other infant formula (powder) other than NeoSure after discharge with calories intake ≥25% of the required daily total calories

Hospital based preterm infants