Cerebral palsy (CP) is most often spotted through delays in physical milestones and differences in how a baby moves, feels when held, or uses their body. About 1 in 345 children in the United States are identified with CP, and while diagnosis has historically happened between 12 and 24 months, specialists can now reliably identify it as early as 3 to 12 months using newer assessment tools. The earlier it’s caught, the sooner a child can begin therapies that make a real difference.
Signs in Babies Under 6 Months
The earliest clues tend to show up in how your baby feels in your arms and how they hold their body. A baby who cannot hold up their head when you pick them up from lying on their back may be showing a sign worth watching. When you lift them, their legs may stiffen or scissor (cross over each other). Some babies feel unusually floppy, like a rag doll, while others feel rigid and stiff. Both extremes of muscle tone can point to CP.
One particularly recognizable pattern: when held against your chest, the baby constantly pushes away from you by overextending their back and neck. This isn’t the normal squirming of a restless infant. It looks like the baby is arching backward forcefully, and it happens repeatedly rather than just occasionally.
Feeding difficulties can also appear early. Babies with CP may have trouble latching, sucking, or swallowing during breastfeeding or bottle feeding. Frequent gagging, coughing, or choking during feeds is common. In one study of children with CP who were fed by mouth, 56% coughed during feeding, 69% gagged, and 66% experienced choking. Excessive drooling beyond what’s typical for the age can be another sign, since the same muscle control issues that affect limbs can affect the mouth and throat.
Milestone Delays to Watch For
Developmental delays are the single biggest indicator. The key gross motor milestones that doctors track in relation to CP are:
- Head control by around 2 months
- Rolling over by around 4 months
- Sitting up by around 6 months
- Walking by around 12 months
Missing one milestone by a few weeks isn’t automatically cause for alarm. Babies develop at different rates, and premature babies often reach milestones later based on their adjusted age (calculated from their due date, not their birth date). What raises concern is a pattern: consistently falling behind across multiple milestones, or missing a milestone by a wide margin. A baby who isn’t sitting with support at 9 months or showing no interest in pulling to stand well past their first birthday warrants a closer look.
One-Sided Movement and Early Hand Preference
Most babies don’t develop a true hand preference until they’re toddlers. If your baby consistently reaches for toys with one hand while ignoring the other, or crawls by dragging one side of their body, that asymmetry is a red flag. Research shows that differences in reaching and grasping between the two hands can become visible as early as 4 to 5 months of age in infants who later receive a CP diagnosis.
This matters because CP often affects one side of the body more than the other (a type called hemiplegia). A baby who always fists one hand while the other moves freely, or who only bats at dangling toys with the same arm, is showing a pattern that goes beyond normal preference.
Reflexes That Don’t Fade on Schedule
Newborns are born with a set of automatic reflexes that normally disappear as the brain matures. When these reflexes stick around too long, it can signal that something in the brain’s development has gone differently.
The asymmetrical tonic neck reflex is the “fencing” pose: when a baby’s head turns to one side, the arm on that side extends while the opposite arm bends. This normally fades between 3 and 9 months. The tonic labyrinthine reflex, which causes a baby to stiffen or arch when tilted backward, typically disappears by 2 to 4 months. A third reflex, the symmetrical tonic neck reflex, emerges around 6 to 9 months and integrates by 9 to 11 months. When any of these persist well beyond their expected window, it can interfere with voluntary movement and is something doctors specifically check for when evaluating a baby for CP.
You won’t necessarily test for these at home, but you may notice their effects. A baby whose arms and legs seem to move involuntarily when their head turns, or who can’t seem to relax out of certain postures, may be showing retained reflexes.
What Increases the Risk
Certain babies are more likely to develop CP, and knowing the risk factors can help you stay alert. Premature birth is the most significant one. Babies born before 37 weeks, and especially those born before 32 weeks, have a substantially higher rate of CP than full-term infants. Low birth weight (under about 5.5 pounds) is another major factor.
Other risk factors include complications during delivery that reduce oxygen to the brain, infections during pregnancy (such as certain viral infections), multiple births (twins or triplets), and jaundice that becomes severe. Having one or more risk factors doesn’t mean CP is inevitable, but it does mean closer monitoring is worthwhile.
How Doctors Confirm a Diagnosis
If you bring concerns to your pediatrician, they’ll likely start with a physical exam and a review of your baby’s developmental history. From there, three tools form the gold standard for early diagnosis.
The General Movements Assessment is a simple but powerful tool used from the preterm period up to 5 months of age. A clinician records a short video of your baby lying on their back and moving freely, then analyzes the quality of those movements. Healthy babies produce complex, fluid, varied movements. Babies at risk for CP tend to show cramped, synchronized, or monotonous patterns instead. It’s painless and non-invasive.
The Hammersmith Infant Neurological Examination is a standardized assessment used between 3 and 24 months. It evaluates posture, movement, muscle tone, reflexes, and how well the cranial nerves are working (things like eye movement and facial expressions). The scoring system helps quantify how a baby’s neurological development compares to what’s expected.
Brain imaging, typically an MRI, gives doctors a direct look at the brain’s structure. It can reveal areas of injury or abnormal development that explain the motor symptoms. Used together, these three tools provide a much more accurate diagnosis than any single test alone.
In one study tracking how early diagnosis clinics performed in the real world, high risk was identified at an average of 4.4 months, early intervention began by 4.7 months, and a confirmed CP diagnosis was made at an average of 8.5 months. That’s a major improvement over the old norm of waiting until age 2.
What to Do if You Notice Signs
Trust your instincts. Parents are often the first to sense something is different, and bringing those observations to your pediatrician is the right move. Be specific about what you’ve noticed: “She always reaches with her left hand and keeps her right fist closed,” or “He goes stiff and arches his back every time I pick him up.” Concrete descriptions help your doctor decide on next steps.
If your pediatrician shares your concern, the typical path involves two simultaneous referrals. One is to a specialist for evaluation, usually a pediatric neurologist or a developmental-behavioral pediatrician. The other is to your state’s Early Intervention program, which provides therapy services (like physical therapy and occupational therapy) for children under age 3 who have developmental delays or disabilities. You don’t need a confirmed diagnosis to qualify for Early Intervention. A referral based on suspected delay is enough to get the process started.
Starting therapy early matters because a baby’s brain is at its most adaptable during the first year or two of life. Even before a formal diagnosis is confirmed, physical therapy and occupational therapy can help a baby build strength, improve movement patterns, and develop skills they’ll need as they grow. The weeks and months spent waiting for a definitive label don’t have to be lost time.