Persistant hypoxemia in the newborn confers, even isolated, an abnormal clinical situation, that needs to be addressed for an adequate diagnosis and an optimal treatment.

If during the first hours of life, hypoxemia is frequent and often transient, beyond that, it is necessary to search the various etiological conditions such as a critical congenital heart disease (CCHD) or a non cardiac affection (sepsis, anemia, respiratory disease).

Newborn pulse oximetry screening identifies babies with critical congenital heart disease (CCHD) based on the rational that they frequently have a degree of hypoxemia that may be clinically undetectable. CCHDs are life-threatening forms of congenital heart disease (CHD) occuring in 2-3/1000 live births but accounting for 3%-7.5% of infant deaths.

Early detection is beneficial because of acute collapse, if not resulting in death, is associated with a worse surgical and neurodevelopmental outcome.

Currently, screening for CCHD involves antenatal ultrasound scanning and post-natal physical examination. Although antenatal detection rates have improved over recent years and can be as high as 70%-80% in some centers, this is not consistent. Indeed, in "Nouvelle Aquitaine" overall <50% of CCHDs are detected before birth. In addition, up to a third of infants with CCHD may be missed on post-natal examination. Pulse oximetry screening can help to close the "diagnostic gap' that is, increase the detection of babies who slip through the current screening net.

Several large European studies and a subsequent meta-analysis have shown that pulse oximetry screening is a highly specific (99.9%) and moderately sensitive (76.5%) test which increases CCHD detection rates. The high specificity results in a low false-positive rate 0.05% to 0.5%. But those babies with a Positive Test, if they may not have CCHD, they may be diagnosed with other causes of hypoxemia (congenital pneumonia, sepsis, persistent pulmonary hypertension,...). As with CCHD, delayed recognition of these conditions can result in postnatal collapse and significant morbidity and mortality. It is also more useful to consider these conditions as secondary targets of screening and to remember they constitute 30%-70% of false positives. In 2011, the US Health and Human Services Secretary recommended that pulse oximetry screening for CCHD be added to the Recommended Uniform Screening Panel. In Europe, implementation is advanced in such countries as North European Countries, and Switzerland. There isn't yet any European guidance. In France, the implementation is limited to local and transient experiments. The feasibility, usefulness and cost-effectiveness of routine pulse oximetry screening have not been evaluated so far. The French setting has two specificities : 1/ the antenatal detection rate is considered to be rather high. 2/ in contrast to a lot of other European countries, early discharge from the maternity ward before 48 hours of life is not common, decreasing the risk of discharging a baby with undiagnosed CCHD, but not saving babies from collapse.

- The Investigators hypothesis is that routine pulse oximetry screening in asymptomatic newborns would allow to reduce the incidence of complications related to CCHDs as well as those related to non cardiac pathologies for a reasonable cost for the French Health Care System.

Inclusion Criteria:

BEFORE Period: newborns

• aged at birth superior or equal to 35 weeks of gestation (≥ 35+ 0 days weeks of gestation)
• borned in metropolitan France in involved maternity wards.
• Asymptomatic before the screening (no respiratory signs, neither collapse or cardiac arrest).

AFTER Period: newborns

• aged at birth superior or equal to 35 weeks of gestation (≥ 35+ 0 days weeks of gestation)
• borned in metropolitan France in involved maternity wards.
• Asymptomatic before the screening (no respiratory signs, neither collapse or cardiac arrest).
• With consent done by the 2 parents.
• Parents covered with the French National health insurance

Exclusion Criteria:

• Newborns with a prenatally diagnosed congenital cyanotic malformation or any other cyanotic affection.
• Newborns with a postnatal pre-screening diagnosed congenital cyanotic malformation or any other cyanotic affection.