The investigators conducted this retrospective study in a large single center with an annual birth of more than 20,000 newborns, from January 1, 2018 to December 31, 2019, to confirm the applicability and accuracy of pulse oximetry (POX) combined cardio-auscultation to screen congenital heart disease for neonates.

All consecutive newborn babies were eligible, irrespective of gestational age, NICU admission, symptom presence or prenatal diagnosis.

This study was approved by institutional ethical review board of Linyi Maternal and Child Healthcare Hospital. Spoken informed consent was obtained from the participating babies' parents.

Physicians from departments of neonatal medicine and developmental medicine undertake auscultation screening. When abnormal murmur occurred, an echocardiography would be requested to confirm if the newborn has CHD or not.

Physicians from obstetrics department and nursing staff from neonatal department undertake POX measurement. If a positive POX occurred, an echocardiography would be requested to confirm if the newborn has CHD or not.

Physicians from department of ultrasonography undertake echocardiography confirmation for newborns deemed positive by auscultation or POX.

Inclusion Criteria:

• All consecutive newborn babies delivered in the study center were eligible, irrespective of gestational age, NICU admission, symptom presence or prenatal diagnosis.

Exclusion Criteria:

• None.

The study population focus on the neonates delivered in the two campuses of the study center which is the largest maternal facility in a municipality of 11 million population.