Phrenic Nerve Injury

When a newborn struggles to breathe in the first hours or days after delivery, parents naturally want answers. One uncommon but serious cause of respiratory distress in newborns is phrenic nerve injury, a condition that affects the nerve controlling the diaphragm. While relatively rare, phrenic nerve injury can occur during difficult births and often accompanies other types of birth trauma, particularly brachial plexus injuries.

Understanding this condition helps families recognize symptoms early, ask the right questions, and work with medical teams to ensure their baby receives appropriate respiratory support and, when needed, timely surgical intervention. This page explains what the phrenic nerve does, how injury occurs during birth, what signs to watch for, and what treatment options are available.

What Is The Phrenic Nerve And Why Does It Matter For Newborns?

The phrenic nerve originates primarily from the cervical nerve roots at levels C3 through C5 in the neck. Its main job is to control the diaphragm, the dome-shaped muscle that sits below the lungs and serves as the body’s primary breathing muscle. When the diaphragm contracts, it moves downward and creates space for the lungs to expand and fill with air.

In newborns, the diaphragm does much more of the breathing work compared to older children and adults. Infants rely heavily on diaphragmatic breathing rather than chest wall expansion. This means that when the phrenic nerve is damaged and the diaphragm cannot work properly on one or both sides, a baby can quickly develop respiratory compromise. Even unilateral diaphragm paralysis (affecting just one side) can significantly reduce tidal volumes and make breathing harder for a newborn.

Poor respiratory function in the early days of life can lead to difficulty feeding, inadequate weight gain, and increased risk of lung infections. Because the diaphragm plays such a central role in infant breathing, phrenic nerve dysfunction requires prompt recognition and management.

How Does Phrenic Nerve Injury Happen During Birth?

Birth-related phrenic nerve injury typically results from mechanical trauma during delivery. The most common cause is excessive stretching or traction on the baby’s neck during a difficult vaginal birth. This can occur when:

• The baby’s shoulder becomes stuck behind the mother’s pubic bone (shoulder dystocia)
• Forceps or vacuum extractors are used to assist delivery
• The baby is delivered in breech position (feet or buttocks first)
• There is excessive lateral flexion (side bending) or hyperextension of the baby’s neck

The phrenic nerve travels alongside the upper cervical nerve roots that form the brachial plexus, the network of nerves controlling arm movement. Because of this anatomical relationship, phrenic nerve injury frequently occurs together with brachial plexus birth palsy. Other risk factors associated with both types of nerve injury include large birth weight, prolonged labor, first-time mothers, and male infants.

Outside the delivery room setting, phrenic nerve damage can also occur after cardiothoracic surgery, from malpositioned chest tubes, or during certain vascular procedures in infants and children. However, birth trauma remains the classic cause in the newborn period.

How Common Is Phrenic Nerve Injury In Newborns?

Diaphragmatic paralysis from phrenic nerve injury is considered rare among term newborns. Medical literature describes it as an uncommon cause of neonatal respiratory distress, most often documented in small case series rather than large population studies. When phrenic nerve injury does occur, it typically happens alongside other birth trauma, particularly brachial plexus damage.

In broader pediatric populations beyond the newborn period, phrenic nerve injury accounts for a small fraction of respiratory failure cases. However, when it does occur in infants under one year of age, it carries a high risk of complications and often requires intensive medical management or surgery.

Because phrenic nerve injury often presents together with brachial plexus palsy, any infant diagnosed with a brachial plexus birth injury should be carefully evaluated for signs of respiratory compromise or diaphragm dysfunction.

What Symptoms Suggest A Baby Might Have Phrenic Nerve Injury?

Parents and medical providers may notice several signs that suggest a newborn is having trouble breathing due to diaphragm paralysis:

• Rapid breathing (tachypnea) or working hard to breathe
• Flaring of the nostrils with each breath
• Visible retractions (chest wall pulling inward) between or below the ribs
• Asymmetric chest movement, with one side moving less than the other
• Paradoxical or “see-saw” abdominal motion, where the abdomen moves inward when the baby tries to inhale
• Bluish skin color (cyanosis), especially around the lips or face
• Worsening respiratory distress when lying flat on the back

Many babies with phrenic nerve injury have difficulty being weaned from supplemental oxygen or mechanical ventilation in the nursery. Sometimes the respiratory distress gets attributed initially to other causes such as pneumonia, infection, or retained lung fluid, and the underlying nerve injury only becomes apparent when symptoms persist despite standard treatments.

On physical examination, doctors may hear reduced breath sounds at the base of the affected lung. If the phrenic nerve injury occurred alongside a brachial plexus injury, the baby may also have weakness or reduced movement in one arm, or an absent Moro reflex on that side. Some infants develop feeding difficulties and fail to gain weight adequately because of the increased energy required for breathing.

How Do Doctors Diagnose Phrenic Nerve Injury?

When phrenic nerve injury is suspected based on symptoms, several imaging and diagnostic tests help confirm the diagnosis:

Chest X-ray is usually the first test performed. It commonly shows an elevated hemidiaphragm on the affected side, meaning one side of the diaphragm appears higher than normal on the image. Serial chest X-rays taken over several days can help determine whether the elevation persists or improves with time.

Ultrasound has become increasingly favored for evaluating diaphragm function in infants. Using specialized modes such as M-mode or TM-mode, ultrasound can directly visualize how much the diaphragm moves during breathing and can detect paradoxical motion, where the paralyzed side moves upward instead of downward when the baby inhales. Research shows ultrasound has high sensitivity for diagnosing diaphragmatic paralysis in infants, and it avoids radiation exposure.

Fluoroscopy provides real-time moving X-ray images that can show abnormal diaphragm motion during breathing. This test may be used in some centers but has largely been replaced by ultrasound for routine evaluation.

Nerve conduction studies and phrenic nerve stimulation can be performed at specialized centers, particularly in cases where the cause is unclear or after cardiac surgery. These tests measure the electrical function of the phrenic nerve directly.

When a brachial plexus injury is also present, providers typically recommend evaluation of respiratory status and imaging to rule out concurrent phrenic nerve damage, since the two injuries often occur together and phrenic involvement can be a negative prognostic sign for nerve recovery.

What Is The Typical Course And Prognosis For Phrenic Nerve Injury?

The natural history of birth-related phrenic nerve injury varies. Some infants experience spontaneous recovery, meaning the nerve function gradually returns on its own without surgical intervention. In documented case series, a portion of affected babies were able to be weaned from mechanical ventilation within one to two weeks and showed satisfactory respiratory improvement with conservative management alone.

However, the majority of infants with phrenic nerve injury do not recover fully without intervention. Persistent diaphragm paralysis can lead to ongoing respiratory insufficiency, recurrent lung infections, difficulty feeding, and poor weight gain. The work of breathing remains elevated, which can affect overall development and quality of life.

Prognosis is generally better for unilateral (one-sided) paralysis compared to bilateral involvement. Bilateral phrenic nerve injury is rare but typically requires more aggressive long-term respiratory support, and in some cases may require specialized interventions such as diaphragm pacing in selected pediatric patients.

When phrenic nerve injury occurs as part of a more extensive brachial plexus avulsion or associated with spinal cord damage, the long-term neurologic and functional outcomes may be more significantly affected, and recovery of arm function may also be limited.

What Treatment Options Are Available For Newborns With Phrenic Nerve Injury?

Initial management focuses on providing adequate respiratory support while giving the nerve time to potentially heal on its own. Treatment approaches include:

Respiratory support tailored to the baby’s needs. This may include supplemental oxygen, continuous positive airway pressure (CPAP), high-flow nasal cannula, or mechanical ventilation if needed to maintain adequate oxygen levels and carbon dioxide removal.

Conservative management with a trial period of observation. Many neonatal intensive care units will provide supportive care for several days to a few weeks to allow for possible spontaneous improvement, particularly when respiratory distress is moderate rather than severe.

Nutritional support to ensure adequate caloric intake despite increased work of breathing. Some babies may need feeding tubes or fortified breast milk or formula to maintain growth.

Monitoring for complications such as pneumonia, atelectasis (lung collapse), or feeding aspiration, which can occur more easily when diaphragm function is impaired.

When an infant cannot be weaned from ventilatory support, continues to have severe respiratory distress, or fails to gain weight appropriately despite medical management, surgical intervention becomes necessary.

When Is Surgery Recommended And What Does It Involve?

The standard surgical treatment for persistent phrenic nerve injury with diaphragm paralysis is called diaphragm plication. This procedure involves surgically tightening and stabilizing the paralyzed portion of the diaphragm to prevent it from moving paradoxically and interfering with breathing.

During plication, the surgeon sutures the floppy, elevated diaphragm to flatten it and hold it in a lower position. This restores more normal chest mechanics and allows the functioning parts of the respiratory system to work more efficiently. The procedure can be performed through an open incision or, in some centers, using minimally invasive video-assisted thoracoscopic surgery (VATS) techniques.

Timing of surgery has been guided by both historical data and evolving practice. Classic pediatric surgical literature suggests that if no clinical or radiographic improvement occurs within about one month, plication should be performed. Many contemporary reviews emphasize earlier intervention, often within the first three to six weeks after birth, particularly when attempts to wean the baby from mechanical support fail.

Early plication helps avoid complications associated with prolonged mechanical ventilation, such as lung injury, infection risk, and developmental delays from extended hospitalization. It also prevents progressive atrophy and scarring of the paralyzed diaphragm muscle, which can make later recovery less likely.

There remains some variation in practice regarding optimal timing, and decisions are typically made by multidisciplinary teams in neonatal intensive care units based on each baby’s specific clinical course. The key principle is that when spontaneous recovery does not occur and the baby cannot maintain adequate respiratory function, timely surgical intervention is the standard of care.

What Outcomes Can Families Expect After Diaphragm Plication?

Most infants who undergo diaphragm plication show significant improvement in respiratory mechanics after surgery. Research demonstrates that plication typically leads to:

• Successful weaning from mechanical ventilation
• Reduced oxygen requirements
• Improved feeding tolerance and weight gain
• Shorter intensive care unit and overall hospital stays

Long-term follow-up studies generally show stable respiratory function after successful plication. Some children may have subtle reductions in pulmonary reserve, meaning their lung function may be slightly lower than average, but most can participate in normal childhood activities without significant limitations. The presence of other medical conditions or complications can affect long-term outcomes.

When phrenic nerve injury is part of a broader pattern of birth trauma involving brachial plexus avulsion or spinal cord injury, the overall neurologic and functional outcomes may be more complex, and children may need ongoing physical therapy, occupational therapy, and developmental support.

Can Phrenic Nerve Injury Be Prevented?

Because phrenic nerve injury typically results from mechanical stress during delivery, prevention strategies overlap with efforts to reduce shoulder dystocia and brachial plexus injuries. Evidence-based approaches include:

• Careful monitoring of fetal size and growth during pregnancy
• Appropriate counseling about delivery options when a large baby is suspected
• Adherence to established protocols for managing shoulder dystocia when it occurs
• Judicious use of forceps and vacuum extraction
• Skilled management of breech deliveries
• Optimal maternal positioning during labor
• Ensuring trained assistance is available for complicated deliveries

There are no vaccines or medications that prevent phrenic nerve injury. Prevention centers on minimizing unnecessary mechanical stress on the infant’s neck and shoulders during the birth process. While not all birth trauma can be prevented, attention to recognized risk factors and adherence to safe delivery practices can reduce the likelihood of injury.

What Support And Resources Are Available For Families?

Babies with phrenic nerve injury typically require care in a neonatal intensive care unit with access to multiple pediatric subspecialties. The care team often includes:

• Neonatologists
• Pediatric surgeons
• Pediatric pulmonologists
• Pediatric neurologists
• Physical and occupational therapists
• Respiratory therapists
• Nutritionists
• Social workers and care coordinators

Major academic medical centers and children’s hospitals in New York and across the country maintain specialized programs capable of diagnosing and treating diaphragmatic paralysis and related birth injuries. Facilities such as NYU Langone, Mount Sinai, Columbia, and other tertiary centers offer high-level neonatal intensive care and pediatric surgical expertise.

Families may need education and support regarding home oxygen equipment, monitoring for signs of respiratory distress, feeding strategies for babies with increased work of breathing, and developmental follow-up. Discharge planning from the NICU typically involves coordination among multiple services to ensure families have the resources and knowledge needed for home care.

National organizations focused on neonatal and pediatric respiratory conditions can connect parents with peer support groups, educational materials, and early intervention services. Hospital-based family support programs often provide counseling, connection to community resources, and assistance navigating complex medical care.

Understanding Your Options And Next Steps

Phrenic nerve injury represents a rare but serious complication that can occur during difficult births. While the diagnosis can be frightening for families, advances in neonatal respiratory care and surgical techniques have improved outcomes significantly. Most infants with phrenic nerve injury who receive timely evaluation and appropriate treatment go on to have stable respiratory function and normal development.

If your baby has been diagnosed with phrenic nerve injury or is experiencing unexplained respiratory distress after birth, working closely with an experienced neonatal care team is essential. Ask questions about imaging findings, the severity of diaphragm dysfunction, the timeline for monitoring versus intervention, and what to expect both short-term and long-term.

NYBirthInjury.com exists to provide trusted medical information and help families understand birth-related conditions and available support options. While every situation is unique, having access to clear, accurate information empowers parents to participate in their child’s care and make informed decisions alongside their medical team.