Transient tachypnoea of the newborn (TTN) is a common cause of hospitalisation in the neonatal period, complicating 1 to 1,5 per cent life birth. Predisposing factors are prematurity, birth after C section, especially before the onset of labor. The main factor leading to this condition is a lack of absorption of the fluid contained in the alveolar space resulting in an early respiratory distress which normally resolves in two to five days with oxygen supplementation.

Meanwhile, some neonates will experience a complicated evolution requiring ventilatory support and hospitalisatioon in neonatal intensive care unit. This complication is not preventable and could result either of a surfactant deficiency (primary or secondary) or a persistent pulmonary hypertension of the neonate (PPHN).

In this study, a cohort of newborn presenting TTN will be followed, in order to evaluate, at initial admission, pulmonary maturation (with fetal lung maturity test and the stable microbubble test) and to seek for PPHN (echochardiography). Therapeutic management will be done according to standard care and classification of the neonate will be performed according to their clinical evolution: group 1 (uncomplicated TTN) and group 2 (complicated TTN).

Statistical analysis will compare results of the tests at initial evaluation in the two groups, and accuracy of the tests to predict a complicated evolution will be established.

Inclusion Criteria:

• Neonate > or = 34 weeks GA admitted in the first 6 hours of life with the suspected diagnosis of TTN (respiratory rate > 60/mn, SpO2 < 90% in room air, ilvermann score > 0
• Parental consent obtained

Exclusion Criteria:

• GA> 42 weeks
• meconial amniotic fluid
• early onset neonatal sepsis (septic shock)
• congenital malformations
• enteral feeding started before admission
• no parental consent