Critical Congenital Heart Diseases (CCHDs) are heart anomalies that if untreated within the first year of life, can lead to death. Current strategies for an early diagnosis involve fetal echocardiography and physical examination. However, these practices fail to diagnose more than 50% of the cases. Since most CCHDs are hypoxic, the use of pulse oximetry to measure arterial oxygen saturation (SaO2) is considered as a complementary method for their detection.