Brachial plexus injury in newborns

Introduction

Brachial plexus injury in newborns is a nerve damage condition affecting the bundle of nerves (the brachial plexus) that controls shoulder, arm and hand movements. It typically occurs during a difficult delivery, especially if the baby’s shoulders get stuck (shoulder dystocia) or there’s excessive traction on the head and neck. For parents, it can suddenly turn a joyful moment into worry, as they notice weakness or limpness in one arm. From mild tingling to more severe paralysis, symptoms vary widely. In this article, we’ll explore causes, symptoms, diagnosis, treatment options and long-term outlook for brachial plexus injuries in newborns—giving you a complete, evidence-based overview without the jargon.

Definition and Classification

Brachial plexus injury in newborns is defined as damage to the network of nerves emerging from the spinal cord at the neck (C5–T1) that innervate the upper limb. This injury may be classified by severity and timing:

• Neurapraxia: Mild, temporary nerve conduction block, often fully recovers in days to weeks.
• Axonotmesis: More severe, with damage to the axon and surrounding myelin, potential for recovery over months via axonal regeneration.
• Neurotmesis: Complete nerve rupture or avulsion from the spinal cord; often requires surgical intervention and may not fully recover.

Clinically, brachial plexus palsies in newborns are categorized by root involvement:

• Erb-Duchenne palsy (upper trunk, C5–C6)
• Klumpke palsy (lower trunk, C8–T1)
• Complete plexus palsy (C5–T1)

Affected systems include the sensory and motor pathways of the arm. While many cases are unilateral, rare bilateral presentations exist. Prompt classification guides treatment planning and prognostication.

Causes and Risk Factors

The exact mechanism of brachial plexus injury in newborns is not fully understood, but several key contributors have been identified.

• Birth Trauma: Excessive force or stretching during a difficult vaginal delivery, particularly in cases of shoulder dystocia where the shoulders get stuck behind the mother’s pelvic bone.
• Large Birth Weight: Babies weighing over 4,000 g (macrosomia) have higher risk, especially in mothers with gestational diabetes.
• Prolonged Labor: Extended second stage can necessitate more traction, inadvertently stretching the plexus nerves.
• Instrumental Delivery: Use of forceps or vacuum extractor may add traction on the neck and shoulder region, increasing nerve injury risk.
• Maternal Factors: Gestational diabetes, maternal obesity, or a history of shoulder dystocia in prior deliveries.
• Fetal Positioning: Breech or transverse lie can complicate extraction mechanics and compress the plexus.
• Genetic Predisposition: Though rare, some infants may have a genetic susceptibility affecting nerve resilience, peripheral myelin stability, or connective tissue elasticity.
• Non-Modifiable Risks: Pelvic anatomy, maternal pelvic shape, fetal size and position—these can’t be changed once labor starts.
• Modifiable Risks: Maternal glycemic control, weight management, skilled obstetric maneuvers and planning for macrosomia can reduce risk.

Interestingly, even with all precautions, sometimes brachial plexus injury occurs unpredictably. There’s still an element of chance—like when you think everything is going perfectly but the baby just doesn’t come out smoothly, it can suddenly click and you see the telltale shoulder dystocia event. Research is ongoing into micro-anatomical variations and molecular factors that might predispose certain infants.

Pathophysiology (Mechanisms of Disease)

Under normal conditions, the brachial plexus transmits impulses from the spinal cord to the muscles and skin of the shoulder, arm and hand. In newborns, delicate axons and incomplete myelination render these nerves vulnerable during delivery stress. When excessive traction or compression occurs, several things happen:

• Stretch Injury: Nerve fibers elongate beyond their elastic limit, causing demyelination (loss of insulating myelin sheath) and Wallerian degeneration distal to the injury site.
• Compression Injury: Direct pressure at the nerve roots can impair blood flow, leading to ischemia and secondary axonal damage.
• Avulsion: In severe cases, nerve roots detach from the spinal cord—this is the most severe form (neurotmesis) and disrupts both sensory and motor pathways permanently unless surgically repaired.

Following injury, the body initiates repair via Schwann cell proliferation, macrophage clearance of debris, and axonal regrowth. The speed of axonal regeneration is about 1–3 mm per day, so recovery in neonates can take weeks to months. However, scar tissue formation can impede nerve pathfinding, and incomplete remyelination may lead to persistent weakness or altered sensation. In Erb palsy, muscles like the deltoid, biceps, and rotator cuff lose innervation, causing the classic “waiter’s tip” posture (arm adducted, internally rotated, elbow extended). In Klumpke palsy, intrinsic hand muscles are affected, leading to a “claw hand” deformity.

Symptoms and Clinical Presentation

Symptoms of brachial plexus injury in newborns usually become apparent within minutes to hours after birth. Parents or clinicians might notice an asymmetrical crying face (baby cries more strongly on the uninjured side) or an arm that hangs limply by the side. Presentation can be quite variable:

• Erb-Duchenne Palsy (C5–C6):
  • Arm hangs internally rotated by the side (“waiter’s tip”).
  • Weak or absent shoulder abduction and elbow flexion.
  • Sensation may be reduced over the lateral arm.
• Klumpke Palsy (C8–T1):
  • Hand and wrist limp, with a “clawing” posture.
  • Intrinsic hand muscle weakness, leading to poor grasp.
  • Possible Horner’s syndrome (ptosis, small pupil) if sympathetic fibers are involved.
• Complete Plexus Palsy (C5–T1):
  • Total flaccid paralysis and loss of sensation of the entire arm.
  • Often associated with more severe delivery trauma and skull or clavicle fractures.

In mild neurapraxia, the infant may have only transient weakness or decreased movement in one arm, and within days to weeks, you might see spontaneous improvement—sometimes it’s almost spooky how quickly they start moving again. More severe cases show persistent limpness beyond 3 months, delayed milestones (like reaching, grasping, transferring objects) and muscle atrophy. Pain isn’t usually expressed by neonates in the way older children can, though some may have irritability or feeding difficulties on the affected side. Urgent warning signs include complete loss of reflexes, no improvement by six weeks, or skin changes suggesting complex regional pain syndrome later in infancy.

Diagnosis and Medical Evaluation

Early assessment of brachial plexus injury in newborns starts with a thorough physical exam by a neonatologist or pediatrician. Key steps include:

• History Taking: Details of labor and delivery—duration, shoulder dystocia events, forceps/vacuum use, infant birth weight and maternal risk factors.
• Clinical Examination: Observe spontaneous movements, passive range of motion, muscle tone, and Moro reflex asymmetry. Note any clavicle or humeral fractures (crepitus, swelling).
• Neurological Tests: Manual muscle testing (graded 0–5) for shoulder abduction, elbow flexion, wrist extension and finger movements. Sensory testing via gentle stimuli to different dermatomes.

If diagnosis is unclear, further evaluations may include:

• Electrodiagnostic Studies (EMG/NCS): Typically performed at 3–4 weeks of age to assess degree of axonal damage and distinguish between neuropraxia and more severe lesions. It helps to map which roots are involved.
• Imaging:
  • Ultrasound of the brachial plexus to look for neuroma or thickened nerves.
  • Magnetic Resonance Imaging (MRI) can visualize root avulsions or post-ganglionic lesions.
• Referral: Early involvement of pediatric neurologists, orthopedists, or plastic surgeons skilled in peripheral nerve injuries helps to plan timely interventions.

Differential diagnoses include congenital limb anomalies, humeral or clavicle fractures, septic arthritis of the shoulder, or central causes like cerebral palsy (though cerebral signs are typically bilateral). A clear diagnostic pathway often involves initial conservative observation for 3–4 weeks, with repeat assessments guiding the need for surgical exploration or neurotization if no signs of reinnervation appear.

Which Doctor Should You See for Brachial Plexus Injury in Newborns?

When you suspect your baby has a brachial plexus injury in newborns, start with your pediatrician or family doctor, who can perform an initial exam and refer to specialists. Key professionals include:

• Pediatric Neurologist: Evaluates nerve involvement, orders EMG/NCS, and monitors neurologic recovery.
• Pediatric Orthopedic Surgeon: Assesses musculoskeletal deformities, shoulder function, and potential contractures.
• Pediatric Plastic/Neurosurgeon: Skilled in microsurgical nerve reconstruction (nerve grafts or transfers) if needed.

For urgent concerns—like complete paralysis, absence of Moro reflex, or suspected root avulsion—go to the neonatal intensive care unit (NICU) or pediatric emergency department. Telemedicine can be a helpful supplement: many pediatric neurologists and surgeons now offer online consultations to review photos, videos of arm movements, or preliminary test results. This can fast-track a second opinion or clarify whether to schedule in-person evaluation. However, remote care is not a replacement for hands-on physical examination or urgent surgery if indicated. Think of telehealth as a way to ask follow-up questions, get guidance on stretching exercises, or discuss the next steps without another long drive—yet always heed recommendations for in-person visits when serious concerns arise.

Treatment Options and Management

Management of brachial plexus injury in newborns depends on severity:

• Conservative Therapy: For neurapraxia and mild axonotmesis. Includes gentle passive range-of-motion exercises, positioning to prevent shoulder contractures, and regular follow-up. Parents learn stretching techniques—like gentle elbow and wrist flexion/extension—to promote joint mobility.
• Physical and Occupational Therapy: Starts within days of birth, focusing on stimulating active movement, improving sensory feedback, and preventing muscle atrophy. Therapists use play-based activities to encourage grasping and reach.
• Surgical Intervention:
  • Nerve Grafting: Harvesting sural nerve segments to bridge gaps in damaged brachial plexus.
  • Nerve Transfers (Neurotization): Redirecting a redundant donor nerve (e.g., spinal accessory nerve) to reinnervate key muscles (like the biceps).
  • Timing: Optimal window is between 3–9 months of age if spontaneous improvement is insufficient by 3–4 months.
• Orthopedic Procedures: For long-term joint stability and alignment. Includes muscle tendon transfers (e.g., latissimus dorsi transfer), contracture release, or shoulder derotation osteotomy in older children.
• Pain Management: Newborns rarely vocalize nerve pain, but in toddlers, gabapentin or NSAIDs may help neuropathic discomfort.

First-line therapy emphasizes non-invasive rehabilitation. Surgery is reserved for infants showing no sign of reinnervation by about 3 months or those with complete avulsion. Side effects of surgery may include donor site weakness, scarring, and the need for multiple staged procedures. Yet, when indicated, microsurgical repairs significantly improve functional outcomes and overall quality of life.

Prognosis and Possible Complications

Most mild brachial plexus injuries (neurapraxia) recover fully within 3–6 months as axons regenerate at roughly 1 mm/day. Favorable prognostic factors include:

• Early return of biceps function (by 3 months)
• Isolated Erb palsy (C5–C6) rather than complete plexus involvement
• Absence of root avulsion on imaging or EMG

However, complications can arise, especially in more severe cases:

• Persistent Weakness: Incomplete reinnervation leads to reduced shoulder abduction, elbow flexion or hand grasp strength.
• Joint Contractures: Without adequate movement, joints stiffen. Shoulder internal rotation contracture can limit reach and daily activities.
• Osseous Deformities: Hypoplasia of the clavicle, glenoid, or humeral head from disuse, leading to glenohumeral subluxation or dislocation.
• Chronic Pain: Neuropathic discomfort may emerge later in childhood.
• Psychosocial Impact: Functional deficits can affect play, self-esteem, and schooling, requiring ongoing support.

In general, early intervention and multidisciplinary care improve outcomes. About 80–90% of infants with Erb palsy regain functional arm use without surgery. Complete avulsions have a less optimistic prognosis, with only 40–60% achieving useful function even after nerve transfers.

Prevention and Risk Reduction

While not all brachial plexus injuries in newborns are preventable, several strategies may reduce incidence:

• Maternal Health Optimization: Control gestational diabetes with diet, exercise, and medication as needed to prevent macrosomia. Maintain healthy weight gain.
• Ultrasound Monitoring: Identify large-for-gestational-age fetuses and malpresentation early, allowing planned cesarean delivery if risk is high.
• Skilled Obstetric Maneuvers: Training in McRoberts maneuver, gentle traction, and rotational techniques minimizes stretching force on the plexus. Real-life obstetric teams often rehearse shoulder dystocia drills to improve response times—and yes, sometimes they even use a teddy bear tethered to mimic a stuck shoulder.
• Elective Cesarean Section: For known macrosomic infants (estimated fetal weight >4,500 g), breech presentation or previous shoulder dystocia, C-section can eliminate traction risk during vaginal birth.
• Labor Management: Avoid prolonged second stage by timely decision-making and consider assisted delivery only when necessary.
• Audit and Quality Improvement: Many hospitals now review shoulder dystocia cases in morbidity and mortality meetings to refine protocols.

Despite best practices, unpredictable factors (e.g., fetal shoulder shape) still cause some injuries. Ongoing research into biomarkers and imaging might one day identify at-risk pregnancies more accurately. For now, proactive obstetric planning, skilled hands-on management during delivery, and shared decision-making with parents remain key approaches to minimize risk.

Myths and Realities

Myth 1: Brachial plexus injuries always lead to permanent disability. Reality: Many infants with mild stretch injuries (neurapraxia) fully recover within weeks to months without long-term issues. Studies show up to 85–90% recover arm function spontaneously if biceps movement returns by 3 months.

Myth 2: Only vaginal births can cause brachial plexus injuries. Reality: While vaginal deliveries with shoulder dystocia are most common, cesarean deliveries can also result in injury if extraction involves undue traction—though it’s rarer.

Myth 3: Parents caused this by being too small or in the wrong position. Reality: Brachial plexus injury is typically a delivery complication beyond parental control; it’s not due to maternal fault or behavior.

Myth 4: Surgery always fixes the problem. Reality: Surgical nerve repair or transfers improve function, but full restoration isn’t guaranteed. Recovery depends on injury severity, timing of surgery, and rehabilitation adherence.

Myth 5: No movement for 3 months means no hope. Reality: While early biceps return is a good sign, some babies show delayed but meaningful improvements with ongoing therapy. Each infant’s timeline varies—patience and persistence with rehab can make a big difference.

Myth 6: If one arm is affected, the other will compensate fully without issues. Reality: Overusing the unaffected arm can lead to strain injuries, poor bilateral coordination development, and compensatory posture problems. Balanced physical therapy is essential for both sides.

Debunking myths helps parents and caregivers understand realistic expectations, set appropriate rehabilitation goals, and avoid needless guilt or false hope.

Conclusion

Brachial plexus injury in newborns is a serious but often manageable condition when identified early and treated promptly. With a spectrum from mild neurapraxia to severe avulsion, understanding classification guides both parents and clinicians in choosing the right interventions. Conservative therapy—stretching, physical and occupational therapy—remains first-line for most infants, while timely surgical referral boosts outcomes in more severe cases. Regular follow-up, family support, and a multidisciplinary team approach help optimize function, reduce complications, and ensure the best quality of life. Always seek professional evaluation at the first sign of arm weakness in a newborn, and remember, early action makes a big difference in recovery.

Frequently Asked Questions (FAQ)

• Q1: What causes brachial plexus injury in newborns? A1: Most often excessive traction on the baby’s shoulder or head during a difficult vaginal birth, especially with shoulder dystocia.
• Q2: How soon will I know my baby has this injury? A2: Signs appear immediately or within hours—limp arm, asymmetric Moro reflex, or weak grasp.
• Q3: Is the condition permanent? A3: Many mild cases resolve fully in weeks to months; severe avulsions may need surgery and can have lasting deficits.
• Q4: Which tests confirm diagnosis? A4: Physical exam, EMG/NCS at 3–4 weeks, ultrasound or MRI if root avulsion is suspected.
• Q5: When should surgery be considered? A5: If no active biceps movement returns by 3–4 months, surgical nerve repair or transfer is typically recommended.
• Q6: Can physical therapy alone fix it? A6: For mild stretch injuries, yes—therapy often restores full range; severe injuries may need surgery.
• Q7: Will my baby feel pain? A7: Newborns rarely verbalize nerve pain; older infants might show irritability or avoid using the arm.
• Q8: How long is recovery? A8: Mild palsies recover in 3–6 months; surgical cases may take 1–2 years for maximal improvement.
• Q9: Can prevention eliminate all cases? A9: No—better obstetric management reduces risk but unpredictable factors still cause some injuries.
• Q10: Does C-section prevent brachial plexus palsy? A10: It lowers risk significantly for macrosomic or breech babies, but isn’t foolproof if traction occurs during extraction.
• Q11: Can telemedicine help? A11: Yes—for initial guidance, second opinions, interpreting test results, but it doesn’t replace in-person exams.
• Q12: Will my child need long-term care? A12: Depends on severity; mild cases often need only months of therapy, while complex injuries may need staged surgeries and ongoing rehab.
• Q13: Are there activities to avoid? A13: Avoid prolonged immobilization, encourage gentle movement; monitor for joint contractures with a therapist’s help.
• Q14: Can siblings be affected? A14: Brachial plexus injury in newborns is typically an isolated event per birth; recurrence risk is low unless similar delivery complications arise.
• Q15: When should I seek urgent care? A15: If you see complete flaccidity, no reflexes, skin color changes or suspect related fractures—go to emergency or NICU immediately.