• Due to the increased risk of brain damage, continuous monitoring of the cerebral oxygenation is interesting. The investigators will evaluate the capability of the INVOS Oximeter to detect induced changes in the cerebral regional saturation.
• The purpose of the study is to investigate our hypothesis that cerebral vasoconstriction after oxygen exposure is prolonged in preterm infants compared to term infants.

Preterm infants are at increased risk of brain damage compared with term infants, and cerebral hypoxia is considered to have an important role. The preterm infants are at increased risk of respiratory distress, episodes with low oxygenation, mechanical ventilation, risk of hypocapnia and labile or low blood pressure. These conditions can affect the microcirculation and hence the oxygenation of the brain. Hyperoxia is also a point of interest, since high levels of oxygen can cause vasoconstriction.

The investigators will examine the normal physiological cerebral response to exposure of oxygen in a group of preterm infants with a gestational age (GA) of 32-37 weeks and a group of term infants.

The investigators will do dynamic research with continuously monitoring of the cerebral oxygenation using the INVOS® Cerebral/Somatic Oximeter (Near InfraRed Spectroscopy (NIRS)). Reproducibility is examined by repeated measurements.

There will be no follow-up.

Inclusion Criteria:

• Newborns with a gestational age of 32-40 weeks
• Clinically stable
• +/- CPAP with a oxygen limit below 30%
• Parental consent

Exclusion Criteria:

• Severe birth asphyxia
• Prohibition of oxygen exposure