Transient tachypnea of the newborn (TTN) is a respiratory disorder resulting from fluid accumulation in the lungs. It is also called wet lungs of newborns, transient respiratory distress in the newborn (RDS), neonatal transient tachypnea, retained fetal lung fluid, and prolonged transition.
TTN might lead to mild to moderate breathing problems in babies. Babies with TTN may need assisted breathing and feeding. However, the condition may self-resolve in around 24 to 72 hours for some infants without causing any complications (1).
Read this post to know more about the causes, risk factors, signs, symptoms, diagnosis, management, and prognosis of TTN.
Causes Of Transient Tachypnea Of The Newborn
During fetal life, the baby’s lungs are filled with fluid essential for fetal growth. The hormonal changes that occur before birth signal the baby’s lungs to reabsorb most of the lung fluid. Additional fluid is reabsorbed while the baby passes through the birth canal during delivery. The remaining fluid is reabsorbed when the baby is delivered and breathes on their own.
The baby may develop breathing difficulty if the lungs do not entirely reabsorb the fluid or if there is excess fluid in the lungs. The presence of fluid causes inadequate oxygen to reach the lungs, causing the baby to breathe harder and faster (2). This condition is called transient (short-lived) tachypnea (rapid breathing) of the newborn.
Risk Factors For Transient Tachypnea Of The Newborn
Babies may continue to have fluid in the lungs if the reabsorption is interrupted before birth.
The following factors may increase the risk of developing TTN in some newborns (3).
- Premature babies are more vulnerable to transient tachypnea since their lungs may have more fluid than full-term babies.
- Maternal asthma and diabetes may increase the risk of the condition.
- Babies born of multifetal pregnancy and male babies may have an increased risk of TTN.
- C-section delivery, especially without labor, may cause a higher risk of developing transient tachypnea since babies may not have adequate hormonal changes to trigger lung fluid reabsorption.
Transient tachypnea of the newborn, usually resolves completely without any complications. However, rarely there occur complications like persistent pulmonary hypertension (when blood vessels of the lung don’t open up fully) and air leaks (in the space between lung and chest wall) leading to prolonged requirement of NICU care. Babies born through vaginal delivery usually do not develop TTN.
Signs And Symptoms Of Transient Tachypnea Of The Newborn
The symptoms and signs of transient tachypnea may vary, depending on many factors including the term and amount of fluid in the lungs of the baby. You may notice the following symptoms and signs when a newborn with transient tachypnea breathes (4).
- Rapid breathing, usually more than 60 breaths in a minute
- Nose flaring
- Grunting sounds
- Rib pulling
- Cyanosis (bluish skin) on limbs, lips, and around the mouth
If you notice any of these symptoms in your newborn, seek prompt medical care. These symptoms can also be present in other medical conditions. But irrespective of the cause all of them warrant urgent medical attention.
Diagnosis Of Transient Tachypnea Of The Newborn
Tthe presence and duration of various signs and symptoms helps in diagnosing transient tachypnea of the newborn. Transient tachypnea of the newborn is usually diagnosed by doctors after they have ruled out all other possible causes of breathing difficulty including the more serious ones.
Different hospitals may have different protocols but if breathing issues persist beyond six hours investigations are done, which may include the following:
Streaked and overinflated lungs on X-ray may indicate the condition. Blood tests measure complete blood count to exclude any signs of infections. Pulse oximetry and blood tests could be used to measure oxygen and carbon dioxide levels in the blood (5). Echocardiography may be done to rule out any problems of the heart or of circulation in the lungs.
Lung infections, such as pneumonia or respiratory distress syndrome, may have similar symptoms. Transient tachypnea goes away within a few hours or days as the lung fluid is cleared. Thus, the duration of the symptoms may also help diagnose the condition.
Treatment For Transient Tachypnea Of The Newborn
Treatment strategies may vary based on the baby’s age, severity of symptoms, and health status.
Babies could be admitted to neonatal intensive care units (NICU) and observed continuously for breathing rate, heart rate, and oxygen levels until the transient tachypnea resolves. Treatment options may include the following measures (6).
- Oxygen supplementation through a mask, nasal cannula (prongs), or by keeping the baby under an oxygen hood could be performed until the breathing rate becomes normal.
- Continuous positive airway pressure uses a mechanical breathing machine to ensure continuous oxygen supply through the baby’s airways.
- Tube feeding may be given until the breathing rate is normal since babies may aspirate food into their lungs during rapid breathing. Breast milk or formula feed can be provided through orogastric or nasogastric tubes.
- Intravenous (IV) fluids are given to ensure nutrition and hydration if tube feeding is not possible.
- Antibiotics may be started if infection cannot be confidently ruled out.
Frequently Asked Questions
1. How common is TTN in newborns?
TTN is one of the newborns’ most common respiratory problems and occurs in about 4.0% to 5.7% of full-term newborns and 10.0% of premature babies (7).
2. Is TTN life-threatening?
TTN is rarely fatal but should be diagnosed promptly and accurately to rule out other conditions that may be confused with TTN in newborns (7).
It may take up to three days for the symptoms to resolve in some babies. Usually, babies are discharged 24 hours after their breathing rate and other symptoms become normal. Although some studies have shown association with subsequent development of asthma in some of these children, they usually do not develop breathing issues or any long-term complications due to TTN.
- Fluid accumulating in the lungs after birth can cause transient tachypnea of the newborns, and it disappears as this excess fluid is absorbed.
- C-section delivery, multifetal pregnancy, maternal asthma, and premature birth may increase the newborn’s risk of developing transient tachypnea.
- Rapid breathing, nose flaring, and rib pulling are some common symptoms of this condition.
2. Transient Tachypnea of the Newborn; Lucile Packard Children’s Hospital, Stanford
3. Transient tachypnea – newborn; MedlinePlus; The United States National Library of Medicine
4. Transient Tachypnea of the Newborn;; Columbia University Irving Medical Center
5. Transient Tachypnea of the Newborn;; Children’s Hospital of Philadelphia
6. Transient Tachypnea of the Newborn; University of Rochester Medical Center (URMC)
7. Jing Liu et al. (2014); Diagnosis of Neonatal Transient Tachypnea and Its Differentiation From Respiratory Distress Syndrome Using Lung Ultrasound; MEDICINE Journals