The purpose of this study is to evaluate the impact of implementing a universal pulse oximeter screening as a way to detect critical congenital heart disease in otherwise well-appearing newborns.

Inclusion Criteria:

1. Documentation of informed consent and authorization.
2. Full term and late preterm newborns (EGA 35-44 weeks)
3. On room air
4. Neonates known to have a congenital heart defect at the time of screening, e.g., antenatal diagnosis or diagnosis within the first 24 hours after birth
5. Parents agree to follow-up contact post discharge

Exclusion Criteria:

1. On supplemental oxygen
2. Admitted to the Neonatal Intensive Care Unit
3. Parents do not agree to follow-up
4. Greater than 30 days of age

Neonates known to have a congenital heart defect at the time of screening.