After a long and challenging labor and delivery, your newborn is here. But something appears off about his face. When he yawns, only one side of his mouth moves. The eyelid on the same side doesn’t close all the way.
You have questions for your doctor. He tells you that your infant has facial nerve paralysis, also called palsy, reassuring you that this paralysis improves over a few weeks most of the time.
But you still have questions. You are looking for answers to understand how this could happen to your baby. Did you do something wrong? Was it due to something done during labor and delivery?
WHAT IS FACIAL NERVE PARALYSIS?
The facial nerve is also called the seventh cranial nerve. Facial nerve paralysis is a condition where there is a weakness of the facial muscles on one side of the face.
WHAT CAUSES FACIAL PARALYSIS IN NEWBORNS?
The incidence of facial nerve injury is 0.5% to 1% of live births. Facial nerve paralysis usually occurs due to damage to the seventh cranial nerve. An injury might happen by misapplying the forceps during delivery. It can also occur when the head of the infant presses too long and too hard against the sacral promontory, which is a projection of the sacral bone by the lumbar vertebrae and the coccyx (tail bone).
Facial nerve paralysis can also occur due to errors in facial nerve development during pregnancy. According to FacialPalsy.org, the following are reasons for newborn facial nerve paralysis:
- Birth trauma
- CHARGE Syndrome
- Hemifacial Microsomia
- Moebius Syndrome
- Asymmetric Crying Facies
Let’s look deeper at the possible causes.
Birth trauma leads to the loss of controllable (voluntary) muscle movement and sensory aspects of the muscle in an infant’s face due to pressure on the facial nerve just before or at the time of birth. This pressure can be caused by prolonged pressure of the baby’s face on the mother’s sacral bone as it moves down the birth canal. It can also occur if forceps are used but applied too close to the seventh cranial nerve on the face.
Several factors that are related to this and other birth traumas include:
- Large baby size (such as with gestational or regular diabetes)
- Long labor and delivery
- Use of epidural anesthesia (which can increase the labor time)
- Use of Pitocin (to induce contractions or help increase the strength of contractions if labor stalls)
Most of the time, these factors do not lead to facial nerve palsy or birth trauma.
CHARGE Syndrome was first described in the 1980s to describe the one in every 10,000 births with a group of congenital problems, which is why it is called a syndrome. The letters which make up the word CHARGE stand for the following issues, according to FacialPalsy.org:
- Coloboma of the eye (part of the eye is missing because it has failed to develop properly)
- Heart defects
- Atresia of the choanae (blockage of the passages at the back of the nose)
- Retardation of growth and/or development
- Genital and/or urinary abnormalities
- Ear abnormalities and deafness
CHARGE Syndrome is a genetic condition that can be inherited, although most have a new gene mutation on chromosome 8. A mutation means that they didn’t get the genetic abnormality from their parents but can pass it on to their offspring.
It is rare to identify CHARGE during the pregnancy, although there was a case report of suspicious ultrasound findings from Thailand published in 2021. There were heart defects noted, a probable malformation of the ear, and kidney abnormalities. The physician confirmed the diagnosis after delivery.
Hemifacial microsomia means small half-face. It is a congenital condition with poorly developed muscles on one side of the face. However, in 10 to 15 percent of cases, both sides of the face are affected. This condition affects the ear, mouth, and jaw areas. It may also involve the eye, cheek, neck, other parts of the skull and nerves, and soft tissue.
While cleft lip and palate defects are the most frequent facial congenital disabilities, hemifacial microsomia comes in second, affecting one in every 3,500 to 4,000 births.
This condition, believed to develop during the first trimester of pregnancy, appears random, with no connection to the mother’s health or diet.
On occasion, providers notice problems during an ultrasound. The majority, however, are not identified until after delivery. There may be problems with breathing and eating for more severely affected infants. Surgical procedures, if needed, are timed out over several years to improve the abnormalities.
Moebius Syndrome is a congenital weakness of the facial muscles due to the lack of function of cranial motor nerves, including the facial muscles. It can be due to agenesis (absence) of the facial nerve nucleus, which is much less common. Infants with Moebius syndrome frequently also have other congenital problems.
Asymmetric crying facies are congenital anomalies occurring in one out of 160 live births. The paralysis is limited to the lower lip. It has also been called congenital unilateral lower lip palsy. This palsy can also be due to birth trauma, as noted for facial nerve paralysis, but is more limited in what is affected. There may be other problems in about 10% of the congenital cases, such as heart defects.
SYMPTOMS OF FACIAL PARALYSIS IN NEWBORNS
- The eyelid may not close on the affected side
- The lower face (below the eyes) appears uneven during crying
- The 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)
CAN THE INFANT RECOVER FROM FACIAL PARALYSIS?
Most infants who have facial nerve paralysis due to birth trauma will recover within a few weeks to a few months. The infant will use an eyepatch if the lid doesn’t close entirely until the eyelid muscle recovers. If there are continued problems, surgical intervention may be needed to improve the appearance.
When to Contact a Medical Professional
The diagnosis of facial nerve paralysis typically occurs right after birth. However, parents and physicians may overlook mild cases for several days or weeks.
If the movement of your infant’s mouth looks different on each side when they cry, you should make an appointment with your child’s healthcare provider.
Birth Injuries in Neonates, Pediatrics in Review, Vol. 37 No. 11 NOVEMBER 2016
Hughes CA, Harley EH, Milmoe G, Bala R, Martorella A. Birth Trauma in the Head and Neck. Arch Otolaryngol Head Neck Surg. 1999;125(2):193–199. doi:10.1001/archotol.125.2.193
Picciolini et al. Moebius syndrome: clinical features, diagnosis, management and early
Intervention. Italian Journal of Pediatrics (2016) 42:56
Photo by: Debabrata Bandyopadhyay
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