What causes congenital facial paralysis?

Updated: Jan 07, 2019
  • Author: Alan D Bruns, MD, FACS; Chief Editor: Arlen D Meyers, MD, MBA  more...
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The cause of congenital facial paralysis is associated with either a traumatic injury or developmental deformities of the brain or facial nerve (cranial nerve VII). [9]


The most frequent cause of unilateral congenital facial palsy is birth trauma related to a difficult delivery. Risk factors include forceps delivery, birth weight of more than 3500 g, and primiparity. [3] The injury from forceps is induced by the pressure of the posterior blade that compresses the bone overlying the vertical segment of the facial canal. [6] The facial nerve is also susceptible to trauma as it exits the stylomastoid foramen, where soft tissue compression can lead to a transient facial neurapraxia. Complete transection of the facial nerve caused by birth trauma is rare. Intrauterine trauma can also occur from pressure on the infant's face by the sacral prominence during labor. [10]

Developmental causes

The causes of developmental facial paralysis are numerous and may be associated with syndromes and teratogens.

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