Transient Tachypnea of the Newborn



  • Early onset of tachypnea (respiratory rate >60 breaths/minute) in the newborn following an uneventful delivery
  • Symptoms of respiratory distress including mild retractions, expiratory grunting, and nasal flaring may occur. Cyanosis is rarely involved.


  • Estimated 4 to 6 per 1,000 live births
  • Incidence is likely underestimated.
  • Most common cause of respiratory distress in newborns
  • Higher in males


  • Early gestation
  • Cesarean section delivery (with or without preceding labor)
  • Male gender
  • Maternal diabetes
  • Macrosomia
  • Low birth weight
  • Maternal history of asthma
  • Unexplained transient tachypnea of the newborn (TTN) in individuals belonging to the same family suggests a genetic predisposition.


  • Vaginal delivery should be recommended in the absence of maternal or fetal indications for cesarean section.
  • Elective cesarean section before 39 weeks’ gestation should be avoided.


Transient pulmonary edema due to delayed clearance of fetal lung fluid


  • During fetal life, pulmonary epithelial cells are secretory, delivering chloride into the alveolar space.
  • Sodium and water follow chloride into the alveoli, establishing and maintaining fetal lung fluid.
  • During labor and delivery, fetal lung fluid is absorbed through a variety of proposed mechanisms:
    • Epithelial cells transition from secretory cells to absorptive cells in response to circulating epinephrine levels, which trigger opening of epithelial sodium channels (ENaC).
    • Compression of the fetal thorax from uterine contractions and passage through the vaginal canal contributes to removal of fluid from the lungs through the pulmonary circulation.
    • Prostaglandin-mediated dilation of lymphatic vessels occurs with resultant absorption of interstitial lung fluid into the lymphatic system.
  • TTN occurs when there is inadequate fluid clearance from the lungs.
  • It is believed that this excess interstitial lung fluid contributes to decreased lung compliance.

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