The association between permanent congenital facial palsy in 61 children and recognized risk factors for traumatic birth was investigated in a retrospective case control study at the Departments of Plastic Surgery, Mount Vernon Hospital, Northwood, Middlesex, and the Hospital for Sick Children, Great Ormond Street, London, UK. The incidence of forceps assisted delivery used in 13.2% of palsied patients was not significantly different from the 10.2% in the normal population. The prevalence of maternal primiparity (39.6%) among mothers of affected babies was no greater than that expected from national data. Big babies weighing >3500 g (18.9%) were fewer in number in the study group than in the general population (38.6%). This study shows that the risk of birth trauma is no higher in children with permanent ‘congenital’ facial palsy than in the general population. An intrauterine rather than a traumatic birth etiology is suggested. 
COMMENT. In this large retrospective study, infants born with facial palsy were no more likely to have required forceps to assist delivery, and other risk factors for traumatic birth were not more prevalent than expected from national data. A commonly held assumption that birth trauma is frequently responsible for permanent congenital facial palsy appears to be false.
The authors of a study of 5 cases of unilateral congenital facial palsy identified in a retrospective review at the Massachusetts Eye and Ear Infirmary, Boston, MA, point out that spontaneous recovery is expected within 4 weeks in 90% of traumatic cases, and the prevalence of atraumatic developmental etiologies has been underemphasized in persistent congenital unilateral facial palsies . The differential diagnosis of developmental cases includes: Mobius syndrome, cardiofacial syndrome, Goldenhar’s syndrome (hemifacial microsomia), Poland’s syndrome, DiGeorge syndrome, Albers-Schonberg disease, sclerostosis, trisomy 13, trisomy 18, and thalidomide embryopathy. In addition to these complex cases, isolated facial palsies may be complete or affect only the upper or lower lip. Electrophysiological and CT studies and especially electroneuronography (ENOG) are essential in the early differentiation of traumatic facial paralyses and those of developmental origin.