Transient tachypnoea of the newborn

Transient tachypnoea of the newborn (TTN), also known as retained fetal fluid or wet lung disease, presents in the neonate as tachypnoea for the first few hours of life, lasting up to one day. The tachypnoea resolves by two days. 

  • amniotic fluid is expressed from the lungs during vaginal delivery and absorbed after birth
  • occurs due to the build-up of fluid in the lungs due to probable reduced mechanical squeeze and reduced capillary and lymphatic removal
  • TTN is more common with Caesarean section deliveries presumably due to lack of thoracic compression as with a vaginal delivery, which in turn causes reduced clearance of fluid from the lungs
Plain radiograph

Depicts a heart failure type pattern but key distinguishing features from congenital heart disease are a normal heart size and rapid resolution of the failure type pattern within days:

  • radiograph shows interstitial oedema and pleural effusions (usually small)
  • normal chest radiograph by 48 hours postpartum

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Article Information

rID: 2198
Systems: Chest, Paediatrics
Section: Pathology
Synonyms or Alternate Spellings:
  • Wet lung
  • Retained fetal fluid
  • TTN
  • Transient tachypnea of newborn
  • Transient tachypnoea of the newborn (TTN)
  • Transient tachypnea of the newborn (TTN)

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