Causes of Brachial Plexus Injuries in Children: Understanding Risk Factors During Childbirth

Brachial plexus injuries in newborns are a significant concern in pediatric neurology, often occurring during the birthing process. These injuries affect the network of nerves responsible for controlling movement and sensation in the arms and hands. While most cases are mild and resolve on their own, some can lead to long-term disability. Understanding the underlying causes is essential for prevention and early intervention.

Primary Causes of Neonatal Brachial Plexus Injury

One of the leading contributors to brachial plexus damage in infants is macrosomia, a condition where the baby is significantly larger than average at birth—typically weighing more than 4 kilograms (about 8.8 pounds). This increase in fetal size is often linked to improved maternal nutrition and rising rates of gestational diabetes, both of which are associated with modern lifestyle changes. When a large infant passes through the birth canal, the shoulders may become lodged behind the mother's pelvic bone—a complication known as shoulder dystocia.

In such cases, emergency delivery techniques like vacuum extraction or forceps may be used to assist with birth. While these interventions can be life-saving, they also increase mechanical stress on the infant's neck and shoulders. If excessive force is applied during delivery, the brachial plexus nerves can stretch or tear, resulting in partial or complete loss of function in the affected arm.

Maternal Health and Physical Condition

Another critical factor involves the mother's physical health and fitness. With rising levels of obesity and sedentary lifestyles, many expectant mothers enter labor without sufficient strength or endurance to complete a vaginal delivery. Poor maternal conditioning can reduce the effectiveness of pushing during the second stage of labor, increasing the likelihood of prolonged or obstructed labor.

When combined with a large infant, this lack of maternal physical readiness heightens the risk of difficult delivery. Even without medical intervention, the natural forces of labor may place enough strain on the baby's shoulder region to injure the brachial plexus. Therefore, maternal fitness and weight management during pregnancy play a vital role in reducing birth complications.

Combined Risk Factors: When Both Mother and Baby Are at Risk

The highest risk occurs when both factors are present: an overweight mother delivering a macrosomic baby. This combination dramatically increases the chances of shoulder dystocia and the need for assisted delivery methods. In these situations, the probability of nerve trauma rises significantly.

Symptoms of brachial plexus injury in newborns may include weakness or paralysis in one arm, limited range of motion, muscle atrophy over time, and a characteristic "waiter's tip" posture where the wrist droops and the hand turns inward. Early diagnosis through physical examination and imaging studies is crucial for initiating timely treatment, which may involve physical therapy, occupational therapy, or, in severe cases, surgical repair.

Preventive strategies such as proper prenatal care, monitoring fetal growth, managing maternal weight gain, and preparing for possible cesarean delivery in high-risk pregnancies can greatly reduce the incidence of these injuries. As awareness grows among healthcare providers and expecting parents, the goal is to ensure safer deliveries and healthier outcomes for every child.