Motor Delays: When a Child Is Late to Sit, Crawl or Walk

Motor milestones: what is typical

Children develop at different rates, so milestones are given as ranges. The ages below are those by which most children (about 75% or more, by the CDC's updated checklists) have reached each skill. Adjust for prematurity up to age 2 by subtracting the number of weeks born early.

Signs of motor delay

In babies

• poor head control after 4 months
• feeling floppy when held, slipping through your hands under the arms
• very stiff legs or arms, or legs that scissor (cross) when lifted
• not rolling by 6 to 7 months, or not sitting by 9 months
• strongly preferring one hand before 12 months, which may mean weakness on the other side
• not bearing weight on the legs when held standing by about 9 to 12 months

In toddlers and young children

• not walking by 18 months
• walking on toes all the time, or an unusual gait
• getting up from the floor by "climbing up" the legs with the hands (Gowers' sign), a warning sign of muscle disease
• frequent falls, clumsiness and trouble with stairs, running or jumping
• difficulty using a spoon, buttons, crayons or scissors compared with peers

Causes of motor delays

Common and often temporary

• Prematurity: premature babies reach milestones later. Use corrected age.
• Limited floor time: babies who spend little time on their tummies or much time in car seats, bouncers and carriers may sit and crawl later.
• Normal variation: some healthy children skip crawling or walk at 16 to 18 months.
• Illness or long hospital stays.

Low muscle tone (hypotonia)

Hypotonia means floppy muscles. It may be benign and improve over time, or linked to genetic conditions such as Down syndrome and Prader-Willi syndrome, brain conditions or muscle disease.

Brain and nervous system conditions

• Cerebral palsy: the most common physical disability of childhood, caused by injury to the developing brain before, during or soon after birth. Signs include stiffness, early hand preference, persistent baby reflexes and delayed sitting and walking.
• Genetic and chromosomal syndromes.
• Brain malformations and hydrocephalus.
• Autism spectrum disorder and global developmental delay, where motor delay occurs alongside speech and social delays.

Muscle and nerve diseases

• Spinal muscular atrophy: loss of nerve cells controlling muscles, causing weakness and floppiness. Early treatment greatly improves outcomes, and many US states screen newborns for it.
• Duchenne and other muscular dystrophies: boys walk late, fall often, have enlarged calves and use their hands to stand up.
• Charcot-Marie-Tooth disease and other neuropathies.

Coordination disorders

Developmental coordination disorder (dyspraxia) affects planning and coordinating movement. Children are clumsy, slow to learn skills such as dressing, riding a bike and handwriting, but have normal strength and intelligence.

Other causes

• joint and bone problems, such as hip dysplasia
• vision problems
• underactive thyroid, nutrition problems and rickets
• environmental factors such as lead exposure

How motor delays are assessed

Pediatricians use developmental screening at well-child visits, with formal screening tools at 9, 18 and 30 months recommended by the American Academy of Pediatrics. If a delay is suspected, the doctor will:

1. take a history of pregnancy, birth, milestones, family history and any loss of skills
2. examine muscle tone, strength, reflexes, posture, joints, head size, skin and eyes
3. watch how the child moves, sits, stands and walks

Depending on the findings, tests may include a creatine kinase (CK) blood test for muscle disease, thyroid tests, genetic testing, brain MRI, nerve studies and hearing and vision tests. Referral to a developmental pediatrician, pediatric neurologist or physical therapist is common.

Treatment and support

• Early intervention: in the US, children under 3 can be evaluated for free through state early intervention programs (IDEA Part C), without needing a diagnosis. Older children can get help through the school district.
• Physical therapy: builds strength, balance and gross motor skills.
• Occupational therapy: develops hand skills, self-care and handwriting.
• Orthotics and equipment: ankle-foot orthoses, walkers and supportive seating.
• Medical treatment: such as gene-targeted therapy for spinal muscular atrophy, or spasticity treatments for cerebral palsy.

Activities to try at home

• plenty of supervised tummy time from birth, building up to a total of about an hour a day by 3 months
• floor play rather than long periods in seats and walkers (baby walkers are not recommended because of injury risk)
• toys just out of reach to encourage rolling and crawling
• stacking, sorting, play dough and crayons for hand skills
• playground play, balls and balance games for older children

Frequently asked questions

What is a motor delay?

A motor delay means a child develops movement skills, such as sitting, crawling, walking or grasping, later than most children their age. Gross motor delays involve large muscles. Fine motor delays involve hand and finger skills. Some children catch up, while others have an underlying condition.

When should I worry about my baby not sitting up?

Most babies sit without support by about 9 months. Talk to your pediatrician if your baby is not sitting alone by 9 months, has poor head control after 4 months, or feels very floppy or stiff. Adjust for prematurity when judging milestones.

Is it normal for a child not to walk at 15 months?

Many healthy children walk between 9 and 18 months, so not walking at 15 months can be normal, especially if the child cruises along furniture. A child who is not walking by 18 months should be evaluated, as should any child who has stopped walking or shows weakness.

Do children with motor delays catch up?

Many do, especially when the delay is mild, related to prematurity, or due to limited practice. Children with conditions such as cerebral palsy or muscle disease improve with therapy but may have lasting differences. Early intervention gives every child the best chance.

Can motor delay be a sign of autism?

Motor delays and clumsiness are common in autistic children, but motor delay alone does not mean autism. Autism is diagnosed based on social communication differences and restricted or repetitive behaviors. A child with several types of delay should have a full developmental assessment.