Prevention should be considered for all pregnant women, but especially for women with a previous child with brachial plexus injury because 14% of siblings are likely to be affected. Preventive measures include avoidance of the following: weight gain during pregnancy, heavy sedation during delivery, and prolonged stage two labor. In addition, a mother with a child with an obstetric brachial plexus lesion should be evaluated for uterine deformities. Delivery by cesarean section helps to avoid obstetrical brachial plexus palsy by preventing shoulder dystocia; nevertheless, 3.6% to 11.4% of patients with obstetrical brachial plexus palsy are born by elective or emergency cesarean section.

Congenital chickenpox infection may produce brachial plexus damage. The damage usually involves the cervical anterior horn motor neurons. Other central nervous system areas may be involved. Clinical manifestations include arm monoparesis and cutaneous scarring (Figure 264.1). Horner syndrome may also be present. Congenital chickenpox is the result of fetal infection by the varicella virus during early pregnancy. No specific treatment is available. Physical therapy is recommended. Surgical treatment of limb deformities and tendon transplant can be attempted when the patient is older.

A	B

Figure 264.1.— Intrauterine chickenpox infection. [A] Left Horner syndrome, atrophy of the left arm and absence of the left thumb. [B] Scar formation in shoulder region.