Transient tachypnoea of the newborn

Also known as wet lung syndrome · type II respiratory distress syndrome · retained fetal lung fluid

Self-limiting neonatal respiratory distress caused by delayed clearance of fetal lung fluid, most common in term and late-preterm infants delivered by elective caesarean without labour.

high10 referencesUpdated 12 July 202610 min readVerification in progress

Practise this topic

Overview & Definition

A well, term or late-preterm baby who is grunting and breathing fast in the first few hours of life is the classic presentation that turns out to be transient tachypnoea of the newborn (TTN). The problem is delayed clearance of the fluid that normally fills the fetal alveoli, so the lungs behave as if they are still partly "wet" until absorption catches up over the first day or two. ^[2]

TTN is also called "wet lung syndrome" or type II respiratory distress, and it is the single most common cause of respiratory distress in term and late-preterm infants. The reassuring feature is the course: symptoms peak within the first day and almost always resolve within 72 hours without surfactant or invasive ventilation, provided oxygen needs stay modest and an alternative diagnosis has been excluded. ^[1]

References10Show

[1]Niu Y, Han D, Kou C Diagnostic accuracy of lung ultrasound for transient tachypnea of the newborn: a meta-analysis. Front Pediatr, 2026.PMID 42422445
[2]Süvari L, Janér C, Helve O Postnatal gene expression of airway epithelial sodium transporters associated with birth stress in humans. Pediatr Pulmonol, 2019.PMID 30920175
[3]Atasay B, Ergun H, Okulu E The association between cord hormones and transient tachypnea of newborn in late preterm and term neonates who were delivered by cesarean section. J Matern Fetal Neonatal Med, 2013.PMID 23311764
[4]Dhaka A, Kumar S, Singh P Nebulized salbutamol for the treatment of transient tachypnea of the newborn: a randomized controlled trial. J Perinatol, 2025.PMID 39690178
[5]Choobdar FA, Vahedi Z, Mazouri A Safety and Efficacy of 2.5 mg and 1.25 mg Nebulized Salbutamol Compared with Placebo on Transient Tachypnea of the Newborns: A Triple-Blind Phase II/III Parallel Randomized Controlled Trial. J Aerosol Med Pulm Drug Deliv, 2024.PMID 38687321
[6]Priyadarshi M, Kaur A, Dhaka A Effect of Nebulized Salbutamol on Lung Ultrasound Aeration Score in Transient Tachypnea of Newborn. Indian J Pediatr, 2026.PMID 41483397
[7]Liem JJ, Huq SI, Ekuma O Transient tachypnea of the newborn may be an early clinical manifestation of wheezing symptoms. J Pediatr, 2007.PMID 17586187
[8]Can Oksay S, Sahin MK, Bilgin G Is Transient Tachypnea of the Newborn a Risk Factor for Bronchiolitis in the First Two Years of Life? A Population-Based Birth Cohort Study. Medeniyet Med J, 2025.PMID 41018067
[9]Lu K, Chen X, Zhu W Terbutaline alleviates the lung injury in the neonatal rats exposed to endotoxin: Potential roles of epithelial sodium channels. Pediatr Pulmonol, 2019.PMID 30644180
[10]Alhowary AA, Altal O, Khasawneh W Mode of Anesthesia During Cesarean Section and Neonatal Morbidity and Mortality: A Cohort Study. Local Reg Anesth, 2026.PMID 42305645