What are the possibilities and next steps for a term baby, born by face to pubis (brow) presentation, with a weak cry since birth, normal breathing, and no feeding difficulties on day of life 2?

Evaluation of Weak Cry in a Term Newborn After Face-to-Pubis Delivery

The most critical immediate step is to perform a focused neurological examination looking for signs of birth trauma, particularly brachial plexus injury, vocal cord paralysis, or intracranial injury, given the abnormal presentation and weak cry since birth. 1

Primary Differential Diagnoses

Birth Trauma-Related Causes (Most Likely Given Presentation)

• Vocal cord paralysis is the third most common congenital laryngeal anomaly and frequently results from birth trauma, particularly with abnormal presentations like face-to-pubis (brow presentation) 2
• Brachial plexus injury affecting the phrenic nerve can cause respiratory muscle weakness and altered cry 1
• Intracranial injury or hemorrhage from difficult delivery may present with weak cry and altered tone 1

Metabolic Causes

• Hypoglycemia is a common provoked cause that can present with weak cry and altered neurological function 3
• Hypocalcemia and hypomagnesemia can cause neuromuscular dysfunction affecting cry quality 3

Maternal Substance Exposure

• SSRI exposure presents with tremors, irritability, and altered cry within hours to days after birth, lasting 1-4 weeks 1, 3
• Opioid withdrawal causes high-pitched cry and irritability, typically manifesting on postnatal days 2-3 in 55-94% of exposed neonates 1, 3
• Cocaine/stimulant exposure produces neurobehavioral abnormalities including altered cry, most frequently on days 2-3 of life 1
• Benzodiazepine exposure causes tremors with onset from hours to weeks 3

Immediate Evaluation Protocol

History

• Detailed maternal drug history including prescription medications (SSRIs, benzodiazepines, opioids), illicit substances, and caffeine intake 1, 3
• Birth history specifics: duration of labor, instrumentation used, presence of shoulder dystocia, Apgar scores at 1,5, and 10 minutes 1
• Feeding assessment: ability to coordinate suck-swallow-breathe, choking episodes, cyanosis during feeds 2

Physical Examination

• Neurological assessment: tone (hypotonia vs hypertonia), reflexes, presence of focal deficits, abnormal movements 3
• Airway examination: stridor, hoarseness, respiratory distress, oxygen desaturation 2
• Musculoskeletal: asymmetry of movement, Erb's palsy positioning, clavicular fractures 1
• Dysmorphic features: facial asymmetry at rest versus crying, which could indicate depressor anguli oris muscle agenesis 4

Laboratory Workup

• Immediate bedside glucose to identify hypoglycemia 3
• Serum calcium and magnesium to identify electrolyte-provoked causes 3
• Urine toxicology screen if maternal substance exposure suspected, as cocaine metabolites can be detected for up to 7 days 1

Specialized Testing Based on Findings

If hoarseness or abnormal cry quality:

• Flexible laryngoscopy is essential to visualize vocal cord function and identify paralysis, laryngeal webs, or other congenital anomalies 2
• This should be performed urgently if associated with severe respiratory distress, oxygen desaturation, or apnea 2

If focal neurological findings or seizure concern:

• Neuroimaging (head ultrasound or MRI) to evaluate for intracranial hemorrhage or structural abnormalities 3
• EEG if seizures suspected, though jitteriness differs from seizures by being stimulus-sensitive and ceasing with passive flexion 3

If examination reveals upper airway abnormality:

• Examination of both upper and lower airways is important, as concomitant abnormalities below the epiglottis occur in up to 68% of cases 2

Management Priorities

Immediate Interventions

• Reverse any identified metabolic derangements immediately (hypoglycemia, hypocalcemia, hypomagnesemia) 3
• Maintain normothermia (36.5°C-37.5°C) as hypothermia increases neonatal morbidity 1
• Ensure adequate oxygenation without routine supplementation, which may cause harm 1

If Maternal Substance Exposure Confirmed

• Neonatal drug withdrawal management using appropriate scoring systems (designed for opioid withdrawal) 1
• Symptoms typically resolve within 1-2 weeks for SSRIs, but may persist up to 4 weeks 1
• Barbiturate withdrawal may have delayed onset up to 10-14 days 1

If Vocal Cord Paralysis Identified

• Otolaryngology consultation for management and assessment of swallowing function 2
• Evaluate for associated conditions: Arnold-Chiari malformation, hydrocephalus, or mediastinal pathology 2

Critical Pitfalls to Avoid

• Do not assume benign causes without excluding birth trauma in the setting of abnormal presentation 1
• Do not delay laryngoscopy if hoarseness or abnormal cry persists, as vocal cord paralysis requires early identification 2
• Do not miss maternal substance exposure by failing to obtain comprehensive drug history, as withdrawal symptoms peak on days 2-3 1, 3
• Do not overlook metabolic causes which are easily reversible but can cause significant morbidity if untreated 3

Reassurance and Follow-up

If all organic causes are excluded and metabolic parameters are normal, parents should be reassured about the benign nature and excellent prognosis 3. However, given the abnormal presentation at delivery and persistent weak cry since birth, organic causes must be systematically excluded before providing reassurance 1.