Why My Baby Isn’t Moving One Side of Their Face

Noticing that your baby’s face doesn’t move the same way on both sides can be frightening. Maybe you’ve observed that when your newborn cries, one corner of their mouth doesn’t pull down like the other. Perhaps one eye doesn’t close completely during sleep, or their smile seems lopsided. These observations often send parents searching for answers in the middle of the night, worried about what might be wrong.

Facial asymmetry or weakness in babies is more common than many parents realize. While it always warrants attention from your pediatrician, it’s often temporary and treatable. Understanding the possible causes, knowing what to watch for, and learning when to seek immediate care can help you navigate this unsettling situation with more confidence.

Understanding Facial Movement in Newborns

A baby’s facial expressions depend on the facial nerve, also called the seventh cranial nerve, which controls the muscles responsible for smiling, frowning, closing the eyes, and moving the forehead. When this nerve or the muscles it controls aren’t working properly on one side, you’ll notice that your baby’s face looks or moves differently.

The asymmetry might be subtle, only noticeable when your baby cries, or it might be obvious even when their face is at rest. Some babies can’t fully close one eye, which becomes particularly apparent during sleep. Others may have difficulty latching or feeding on one side because the muscles around the mouth aren’t coordinating properly.

These signs don’t automatically mean something serious is happening, but they do require professional evaluation to determine the cause and appropriate response.

Birth-Related Facial Nerve Injury

The most common reason for one-sided facial weakness in newborns is injury to the facial nerve during delivery. This happens in approximately 1 to 2.4 out of every 1,000 live births, meaning several thousand babies in the United States experience this each year.

During birth, particularly in difficult deliveries, the facial nerve can become compressed or stretched as the baby moves through the birth canal. The nerve runs through a narrow bony canal in the skull near the ear, making it vulnerable to pressure. This pressure can come from the baby’s position against the mother’s pelvis, from the use of forceps or vacuum extraction devices, or from the physician’s hands during delivery.

Babies born after prolonged labor, those who experienced shoulder dystocia (when the shoulder gets stuck during delivery), or those delivered with assistance from instruments face higher risk for this type of nerve injury. However, facial nerve palsy can also occur in completely uncomplicated vaginal deliveries without any instruments, affecting about 0.6% of births.

The injury typically presents immediately after birth. You might notice that when your baby cries, one side of the face moves normally while the other remains relatively still. The affected side may appear smooth, without the typical wrinkles and creases that crying produces. The eye on that side might not close completely, and the corner of the mouth won’t pull down as it should.

The encouraging news is that 80 to 90% of these cases resolve completely within two to eight weeks as the nerve heals naturally. The nerve is usually not severed but compressed or bruised, and it recovers as swelling subsides and normal function returns. During this recovery period, most babies don’t need any specific treatment beyond careful monitoring.

Muscle Tightness and Positional Issues

Sometimes what appears to be facial weakness is actually the result of muscle tightness in the neck causing the baby to favor one side. Congenital muscular torticollis affects about 1 in 250 newborns and occurs when the sternocleidomastoid muscle (the large muscle running down the side of the neck) becomes tight or shortened.

When a baby has torticollis, they tend to keep their head tilted toward one side and rotated to look toward the other. This persistent head position can lead to facial asymmetry over time, not because the facial muscles themselves are weak, but because the baby’s head is always turned the same way.

This constant positioning can cause the skull to flatten on one side, a condition called positional plagiocephaly. As the head shape changes, the face can appear asymmetric, with one cheek looking fuller, one ear sitting further forward, or one eye appearing slightly different in size or position compared to the other. About 90% of babies with untreated torticollis develop some degree of plagiocephaly.

Torticollis typically develops from the baby’s position in the womb, particularly in breech presentations, or from birth trauma that causes the neck muscle to tighten or develop scar tissue. Babies who consistently lie with their head turned the same direction after birth can also develop or worsen the condition.

Unlike true facial nerve injury, babies with torticollis-related asymmetry have normal facial movement when you gently turn their head to a neutral position. The asymmetry is structural rather than neurological. Physical therapy with stretching exercises can treat torticollis effectively, especially when started before 12 months of age. Without treatment, the muscle tightness and resulting asymmetry can become permanent.

When Facial Asymmetry Signals Something More Serious

While most cases of facial asymmetry in babies have benign causes that resolve with time or simple treatment, certain situations require immediate medical attention because they may indicate a more serious underlying problem.

Stroke in Newborns

Neonatal stroke occurs in approximately 1 in 4,000 births, affecting about 1,000 babies in the United States each year. When a stroke affects one side of the brain, it can cause weakness on the opposite side of the body, including the face. Unlike isolated facial nerve injury from birth trauma, stroke-related weakness typically affects not just the face but also the arm and leg on the same side.

Babies who experienced oxygen deprivation during birth (birth asphyxia) or who had bleeding in the brain face higher risk for perinatal stroke. The weakness may be accompanied by seizures, extreme floppiness or stiffness, difficulty feeding, or decreased alertness.

Cerebral Palsy

Cerebral palsy affects 2 to 3 out of every 1,000 live births and results from brain injury that occurs before, during, or shortly after birth. In New York, approximately 300 new cases are identified each year. Spastic hemiplegia, one type of cerebral palsy, causes increased muscle tone and weakness on one side of the body.

Babies with hemiplegic cerebral palsy will show facial asymmetry as part of a broader pattern of one-sided weakness. As they grow, you’ll notice they favor one hand, have difficulty with movements on one side, or show stiffness in the arm or leg on the affected side. Unlike temporary facial nerve palsy, the weakness associated with cerebral palsy persists and becomes more apparent as the baby reaches developmental milestones.

Rare Conditions

Möbius syndrome, though rare (affecting about 1 in 50,000 births), causes facial paralysis on both sides along with difficulty moving the eyes from side to side. Infections such as Lyme disease or tumors compressing the facial nerve can also cause facial weakness, though these are uncommon in newborns.

What to Watch For and When to Call the Doctor

Knowing which symptoms require urgent attention versus which can wait for a regular appointment helps you respond appropriately without unnecessary panic.

Seek emergency care immediately if your baby shows sudden facial drooping accompanied by weakness in an arm or leg, seizures, extreme lethargy, difficulty breathing, or if they become unresponsive. These symptoms could indicate a stroke or other serious neurological emergency.

Contact your pediatrician within 24 to 48 hours if you notice facial asymmetry with poor feeding, an eye that doesn’t close (which can lead to corneal drying and injury), excessive drooling on one side, or if the asymmetry seems to be worsening rather than improving.

Schedule a regular appointment if you observe persistent head tilting, a flat spot developing on your baby’s head, or if facial asymmetry continues beyond two weeks without improvement. While these situations aren’t emergencies, they benefit from professional evaluation and early intervention.

Document what you’re seeing by taking photos and videos of your baby at rest and while crying. Note when you first observed the asymmetry, whether it’s getting better or worse, and any other symptoms you’ve noticed. This information helps your healthcare provider make an accurate diagnosis.

How Doctors Diagnose the Cause

Your pediatrician will start with a thorough physical examination, watching your baby’s facial movements during rest, crying, and feeding. They’ll test the baby’s ability to close both eyes, wrinkle the forehead, and move the mouth symmetrically. They’ll also check for other signs of birth trauma, assess muscle tone throughout the body, and examine the head for any unusual shapes or flat spots.

The doctor will ask detailed questions about the delivery: Was it prolonged? Were instruments used? Was there shoulder dystocia? Did the baby need resuscitation? The answers help determine whether birth trauma likely caused the facial weakness.

For most cases of suspected facial nerve palsy from birth trauma, no additional testing is needed initially. The doctor will recommend close monitoring over the following weeks, watching for improvement as the nerve heals.

If the weakness persists beyond a few weeks, affects both sides of the face, or is accompanied by other concerning symptoms, your doctor may order imaging studies. An MRI can reveal structural problems, bleeding in the brain, or other abnormalities. Electromyography (EMG) can assess nerve function and help determine the extent of nerve damage.

When torticollis is suspected, the diagnosis is typically made through physical examination alone. The doctor will feel for tightness in the neck muscle and assess the range of motion when turning the baby’s head.

Treatment Options and What to Expect

Treatment depends entirely on the underlying cause of the facial asymmetry.

For Birth-Related Facial Nerve Injury

Most cases require only watchful waiting and supportive care. The nerve heals on its own as swelling resolves and normal function gradually returns. During recovery, parents need to protect the eye that doesn’t close completely. Your doctor may recommend using artificial tears during the day and applying eye ointment at night, then gently taping the eyelid closed to prevent the cornea from drying out and becoming damaged.

Feeding may be challenging initially, but most babies adapt. You might need to experiment with different positions or bottle nipples to find what works best. Some babies feed better on one side than the other.

Follow-up appointments allow your pediatrician to monitor progress. If significant improvement hasn’t occurred by 8 to 12 weeks, referral to a pediatric neurologist or otolaryngologist (ear, nose, and throat specialist) may be appropriate for further evaluation.

For Torticollis and Plagiocephaly

Physical therapy is the primary treatment for congenital muscular torticollis. A pediatric physical therapist will teach you specific stretching exercises to perform with your baby several times daily. These gentle stretches help lengthen the tight muscle and increase the range of motion in the neck.

Repositioning strategies are equally important. You’ll learn techniques to encourage your baby to turn their head in the direction they typically avoid, using toys, sounds, and positioning during feeding and sleep to motivate movement. The American Academy of Pediatrics recommends 15 to 30 minutes of supervised tummy time each day, which strengthens neck muscles and prevents flat spots from developing.

For babies who develop significant plagiocephaly despite repositioning efforts, a cranial molding helmet may be recommended if started before 12 months of age. These custom-fitted helmets gently guide head growth into a more symmetrical shape over several months.

When started early, physical therapy for torticollis is highly effective. Most babies show significant improvement within a few months, though treatment may continue for six months to a year to achieve full range of motion and prevent recurrence.

For Serious Neurological Causes

Babies diagnosed with stroke, cerebral palsy, or other neurological conditions require specialized, long-term care coordinated by pediatric neurologists and rehabilitation specialists. Treatment plans are individualized and may include physical therapy, occupational therapy, medications to manage muscle tone or prevent seizures, and ongoing monitoring of development.

Early intervention services make a significant difference in outcomes for children with neurological conditions. In New York, the Early Intervention Program provides free evaluation and services for children from birth to age three who have developmental delays or disabilities. Services are provided in the child’s natural environment, often at home, and are coordinated through the New York State Department of Health.

Prevention and Risk Reduction

While not all causes of facial asymmetry can be prevented, certain steps may reduce risk.

During pregnancy and delivery, appropriate medical management is essential. Difficult deliveries should be handled by experienced providers who can make quick decisions about when instrument assistance is appropriate versus when a cesarean section is safer. New York Public Health Law requires informed consent for high-risk delivery procedures, ensuring parents understand the risks and benefits of interventions like forceps or vacuum extraction.

After birth, simple positioning practices can prevent torticollis and plagiocephaly from developing or worsening. Always place your baby on their back to sleep, following safe sleep guidelines, but vary which end of the crib their head is toward so they turn different directions to look at interesting things in the room. During awake time, provide plenty of supervised tummy time and minimize time in car seats, bouncers, and swings where the head is pressed against a surface.

Alternate which arm you use to hold your baby during feeding and carrying. This encourages them to turn their head both directions and prevents them from developing a strong preference for one side.

Long-Term Outlook

The long-term outlook for babies with facial asymmetry depends on the underlying cause.

For birth-related facial nerve palsy, the prognosis is excellent. The vast majority of babies recover completely within weeks to months, with no lasting effects. Even in the small percentage of cases where some weakness persists, it’s often mild and may only be noticeable to people who know to look for it.

Torticollis treated with early physical therapy typically resolves fully, with babies achieving normal neck range of motion and symmetrical head and facial development. Without treatment, permanent muscle shortening and facial asymmetry can result, but these outcomes are preventable with appropriate intervention.

For babies whose facial weakness stems from cerebral palsy or stroke, the outlook is more variable and depends on the extent of brain injury. Many children with hemiplegia go on to walk, talk, and participate in regular activities, though they may always have some degree of one-sided weakness. Early intervention and ongoing therapy optimize outcomes and help children reach their full potential.

Keeping Perspective During a Stressful Time

Discovering that something seems wrong with your baby’s face triggers understandable anxiety. The face is central to how we recognize and connect with our babies, and any asymmetry can feel alarming and heartbreaking.

Remember that facial asymmetry in newborns is relatively common and usually temporary. The majority of cases resolve on their own or with simple interventions like physical therapy. Your pediatrician is your partner in determining what’s causing the asymmetry and what steps, if any, need to be taken.

Trust your instincts as a parent. You know your baby better than anyone else. If something seems off or if you notice changes, don’t hesitate to reach out to your healthcare provider. Early identification and treatment of any problem always lead to better outcomes.

Keep records of your observations, attend all follow-up appointments, and follow through with recommended therapies. Your active participation in your baby’s care makes a real difference in their recovery and development.

If your baby’s facial weakness resulted from preventable birth trauma, understanding your options is important. Medical providers have a responsibility to manage labor and delivery appropriately, use instruments correctly when needed, and recognize when complications require different interventions. While this article provides educational information about birth injuries, it does not constitute medical or legal advice. Consulting with specialists in both medicine and law can help you understand what happened and what resources may be available to support your child’s care.

Moving Forward With Information and Support

Facial asymmetry in babies spans a spectrum from temporary and benign to serious and requiring intensive intervention. Most cases fall toward the benign end of that spectrum, resolving as nerves heal or responding well to physical therapy.

The key is accurate diagnosis followed by appropriate monitoring or treatment. Your pediatrician can distinguish between conditions that will resolve on their own, those that need therapy, and those rare situations requiring urgent specialist care.

Document what you observe, communicate openly with your healthcare team, and don’t hesitate to seek second opinions if you’re not satisfied with the answers you’re receiving. Your baby’s health and development are too important for anything less than thorough evaluation and clear communication.

Resources like New York State’s Early Intervention Program (accessible through health.ny.gov) provide support for families whose babies need therapy or specialized services. These programs remove financial barriers to care and ensure babies receive the interventions they need during the critical early years when treatment is most effective.

Whether your baby’s facial asymmetry proves to be a temporary issue that resolves in weeks or a longer-term condition requiring ongoing care, you’re not alone. Healthcare providers, therapists, and support networks exist to help you navigate the journey ahead.

This article is for educational purposes only and does not constitute medical or legal advice. Always consult with qualified healthcare providers regarding your baby’s specific symptoms and situation. If you believe your child’s condition resulted from medical negligence during birth, consider speaking with professionals who can evaluate your individual circumstances.