Management of Brachial Plexus Injury in Macrosomic Newborns

Clinical Context and Risk Factors

The American Academy of Family Physicians notes that birth trauma risk is dramatically elevated in macrosomic infants >4,500g born to diabetic mothers, with brachial plexus injury risk increasing 18-to 21-fold compared to normal birth weight infants 1, 2
The American Academy of Family Physicians states that the risk of shoulder dystocia in diabetic pregnancies with birth weight >4,500g ranges from 19.9% to 50%, compared to 9.2-24% in non-diabetic pregnancies 1, 2

The American Academy of Family Physicians recommends documenting the specific pattern of weakness, including the classic "waiter's tip" position, indicating upper trunk (C5-C6) injury 1, 2
The American Academy of Family Physicians suggests assessing grasp reflex, as a preserved grasp reflex with weak Moro suggests upper brachial plexus injury rather than lower plexus involvement 1
The American Academy of Family Physicians advises examining for associated injuries, including clavicular fracture, which occurs with 10-fold increased frequency in macrosomic infants and often accompanies brachial plexus injury 1, 2

The American Academy of Family Physicians recommends plain radiographs of chest/shoulder to exclude clavicular fracture or humeral fracture, both common associated injuries 1, 2

The American Academy of Family Physicians suggests gentle immobilization, positioning the affected arm across the abdomen in a natural position, and avoiding rigid immobilization which can cause joint contractures 1
The American Academy of Family Physicians recommends pain management, providing appropriate analgesia as nerve injuries are painful 1

The American Academy of Family Physicians advises referring to pediatric neurology or orthopedics within 1-2 weeks if weakness persists beyond the first few days 1
The American Academy of Family Physicians recommends initiating physical therapy early (within first 2 weeks) to maintain range of motion and prevent contractures 1

The American Academy of Family Physicians notes that approximately 80-90% of brachial plexus injuries from birth trauma recover fully within 3-6 months with conservative management 1
The American Academy of Family Physicians states that surgical intervention is reserved for cases without recovery by 3-6 months; nerve grafting or nerve transfers may be considered 1

The American Diabetes Association recommends thorough examination for congenital anomalies, including cardiac defects, neural tube defects, and caudal regression, as infants of mothers with uncontrolled diabetes have increased risk 4, 3
The American Academy of Pediatrics suggests considering renal ultrasound if other anomalies are detected, as genitourinary abnormalities are more common 4

The American Academy of Family Physicians advises not delaying radiographs, as clavicular fracture is 10-fold more common in macrosomic infants and must be excluded immediately 1, 2
The American Academy of Family Physicians recommends not providing false reassurance, as while most cases resolve, parents need realistic expectations about the 10-20% risk of permanent deficit 1

The American College of Obstetricians and Gynecologists recommends postpartum diabetes screening, with a 75g oral glucose tolerance test at 4-12 weeks postpartum, as 50-70% lifetime risk of developing type 2 diabetes exists 5, 3
The American College of Obstetricians and Gynecologists advises emphasizing the importance of preconception glycemic control (A1C <6.5%) to reduce macrosomia risk from 20% to 2% in subsequent pregnancies 2, 4, 6