Facial nerve palsy due to birth trauma is the loss of controllable (voluntary) muscle movement in an infant's face due to pressure on a certain nerve in the face just before or at the time of delivery.
Seventh cranial nerve palsy due to birth trauma
Causes, incidence, and risk factors
The infant's facial nerve (also called the seventh cranial nerve) can be damaged just before or at the time of delivery.
Most of the time the cause is unknown. However, a difficult delivery, with or without the use of instruments called forceps, may lead to this condition.
Some factors that can cause birth trauma (injury) include:
Large baby size (may be seen if the mother has diabetes)
Long pregnancy or labor
Use of epidural anesthesia
Use of a medication to cause labor and stronger contractions
However, most of the time these factors do not lead to facial nerve palsy or birth trauma.
The most common form of facial nerve palsy due to birth trauma involves only the lower part of the facial nerve. This part controls the muscles around the lips. The muscle weakness is mainly noticeable when the infant cries.
Lower face (below eyes) appears uneven during crying
Mouth does not move down the same way on both sides while crying
No movement (paralysis) on the affected side of the face (from the forehead to the chin in severe cases)
Signs and tests
A physical exam is usually all that is needed to diagnose this condition. Rarely, a nerve conduction study is needed. This test can pinpoint the exact location of the nerve injury.
Brain imaging tests are not needed unless your doctor thinks there is another problem (such as a tumor or stroke).
In most cases, the infant will be closely monitored to see if the paralysis goes away on its own.
Infants with permanent paralysis need special therapy.
The condition usually goes away on its own in a few months.
Occasionally the facial muscles on the affected side become permanently paralyzed.
Calling your health care provider
The health care provider will usually diagnose this condition while the infant is in the hospital. However, mild cases involving just the lower lip may not be noticed at birth. A parent, grandparent, or other person may notice the problem later.
If the movement of your infant's mouth looks different on each side when he or she cries, you should make an appointment with your child's health care provider.
There is no guaranteed way to prevent pressure injuries in the unborn child. The proper use of forceps and improved childbirth methods have reduced the rate of facial nerve palsy.
Adams-Chapman I, Stoll BJ. Nervous system disorders. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 99.
Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.