Inclusion Criteria:  Neonates with Esophageal Atresia (All, no exclusion criteria); maximum age at enrollment is 3 months. Neonates matched for gestational age without EA, also anticipated to require surgery (Infants >=32 weeks), or also premature (<32 weeks)  Exclusion Criteria (only for infants without EA):  sepsis admission to study hospital after 7 days old expected length of stay <2 weeks