Delayed Motor Milestones: Signs and Causes

Key takeaways

A missed milestone is information, not noise. The CDC checklists list milestones that at least 75% of children reach by the given age, and the working group that revised them said plainly that the goal was to discourage a wait-and-see approach.¹
The range of normal is still wide. Being later than average is different from not progressing, and the direction of travel matters more than any single date.
You can refer your own child. Under three, every state runs a free early intervention evaluation under IDEA Part C and you do not need a doctor to make the referral.⁴
Standardized screening belongs at the 9-, 18- and 30-month visits, and a concern raised at any visit should lead to screening or a direct referral rather than to waiting.³
Losing a skill is different from being late to gain one. A child who was sitting and no longer sits needs prompt medical evaluation, whatever their age.
Asymmetry is one of the most useful early signs. A clear hand preference before about 12 months is not typical and is worth raising.
For babies born preterm, use corrected age until around two years, or the delay you are measuring is mostly prematurity.
Floor time is the intervention you control. Tummy time is positively associated with gross motor development, and time in a walker or seat is time not spent practicing.^5,6

75%of children reach each CDC milestone by the age it is listed, which is why not reaching one is worth raising rather than waiting out
9, 18, 30the well-child visits in months where the AAP says a standardized developmental screen should be done, concern or no concern
$0the cost of an early intervention evaluation under IDEA Part C, at any income, with no doctor’s referral needed

Motor milestones by age, and what to do if your child is not there yet

The ages below follow the CDC's Learn the Signs. Act Early. checklists.² Milestone guidance describes what most children do by a given age, not a deadline.¹ That is the reassuring half, and it is true. The other half is what the 2022 revision was for: the expert group convened by the CDC and the American Academy of Pediatrics set out to clarify when most children can be expected to reach a milestone, in order to discourage a wait-and-see approach, and built the checklists from milestones that at least 75% of children achieve by the listed visit age.¹

So the honest reading is not “every child is different, don’t worry” and not “your child is behind.” It is: three quarters of children are doing this by now, so it is worth a conversation. The right-hand column below is what that conversation looks like.

Age	What most children do	If your child is not there yet
2–4 months	Lifts head during tummy time, holds head steadier when supported, brings hands together	Mention it at the next well-child visit. Increase tummy time in short, frequent sessions rather than long ones.
4–6 months	Rolls in at least one direction, sits with support, pushes up on arms, reaches for objects	Not rolling at all by around 6 months is worth raising. Ask specifically about muscle tone and symmetry.
6–9 months	Sits without support, moves objects between hands, begins moving around	Not sitting without support by around 9 months is worth raising. The 9-month visit already includes a standardized screen.³
9–12 months	Pulls to stand, moves along furniture, may take steps	Not moving around in any way by around 12 months warrants an assessment. Refer to early intervention yourself while you wait for an appointment.
12–18 months	Walks independently, begins climbing, may start running	Not walking by around 18 months is worth raising. The 18-month visit includes a standardized screen.³
18–24 months	Walks well, runs, climbs stairs with help, kicks a ball	Raise it at the 30-month visit at the latest, which also includes a screen.³ Persistent toe walking past age 3 is separately worth asking about.

Not every child crawls, and skipping crawling is not in itself a concern — some children bottom-shuffle, roll, or go straight to walking. What matters is that they are moving around somehow and still gaining skills. Our month-by-month baby milestones and printable milestone tracker cover the full picture across all domains, not just movement.

What matters more than the exact date

Four things tell a clinician more than which week a skill arrived. They are also the four things worth writing down before an appointment, because they are what you will be asked.

Direction of travel
A child who is gaining new skills steadily, even later than average, is a different picture from one who has plateaued. What to do: note the date of the last new skill. “Nothing new since March” is far more useful to a clinician than “he seems behind.”
The overall picture
Motor delay alongside typical communication and play is a different question from motor delay with concerns in several areas. What to do: check the other domains too before the appointment, so you can say which are and are not affected.
Symmetry
Using one side consistently more than the other is worth assessing, and a clear hand preference before around 12 months is not typical. What to do: film 30 seconds of your child reaching for a toy placed directly in front of them. Video is often more use than description.
Quality, not just achievement
How a child moves matters as much as whether they have reached a milestone — a child who only sits by propping forward on both arms has reached it differently from one who sits and plays. What to do: describe what the movement looks like, not just whether it happens.

Signs worth raising with your doctor

Book an appointment if your child:

Is not rolling by around 6 months
Is not sitting without support by around 9 months
Is not moving around in any way by around 12 months
Is not walking by around 18 months
Consistently uses one side of the body more than the other
Feels unusually stiff, or unusually floppy
Has persistently fisted hands past early infancy
Is toe walking persistently past around age 3
Can only sit comfortably in a W-position
Tires far more quickly than children of the same age

None of these means something is wrong. Each one means the question is worth asking now rather than at the next visit.

Contact your doctor promptly if your child has lost a skill

A child who was sitting and no longer sits, was walking and no longer walks, or has lost head control needs prompt medical evaluation regardless of age. Loss of previously acquired skills is investigated differently from delay and should not be monitored at home. See developmental regression.

What to do about a motor delay, step by step

This is the part most pages leave out. If you have a concern today, here is the order that gets a child seen fastest.

Write down what you have noticed, with dates
The date of the last new skill, what the movement looks like, and whether one side differs from the other. Take a short video. This is the single thing that most improves an appointment, and it takes ten minutes.
If your child is under three, refer them to early intervention yourself
Every state runs a program under Part C of the Individuals with Disabilities Education Act.⁴ You do not need a doctor’s referral and the evaluation is free regardless of income or insurance. Search for your state's name plus “early intervention.” Do this first, not after the pediatrician appointment — the two run in parallel and this one has the longer queue.
If your child is three or over, request an evaluation from your school district, in writing
The district must evaluate a child who may need services, and putting the request in writing is what starts the legal timeline. Keep a copy and note the date you sent it.
Book the pediatrician, and ask for a standardized screen by name
The AAP recommends standardized screening at the 9-, 18- and 30-month visits, and says a concern raised at any visit should be followed by screening or a direct referral rather than by watchful waiting.³ If your child is between those ages and you have a concern, you can ask for the screen anyway.
Ask what is being ruled out, and what would change the plan
Two useful questions: what would you expect to see if this were low tone rather than typical variation, and what would make you refer to a specialist? The answers tell you what the next appointment is for.

Why the order matters. Early intervention referral is the step families most often delay, usually because they are waiting for a doctor to suggest it. Nobody has to. Making the referral yourself while the pediatrician appointment is still weeks away can pull an evaluation forward by months, and if the assessment finds nothing, that is a useful answer too.

Motor milestones in premature babies: how to use corrected age

If your baby was born preterm, milestones are judged from corrected age — the age they would be had they been born at term — usually until around two years.

How to work it out: subtract the number of weeks early from your baby’s actual age. A nine-month-old born eight weeks early has a corrected age of seven months, and should be compared against seven-month expectations. Skipping this step is the most common reason a preterm baby looks delayed when they are developing exactly as expected.

What the evidence supports. A Cochrane review of 44 studies and 5,051 participants found that early developmental intervention programs for preterm infants probably improve cognitive and motor outcomes during infancy, on low-certainty evidence, and at preschool age improve cognitive outcomes, on high-certainty evidence. The authors note considerable heterogeneity between studies and that it is not yet clear which types of intervention work best.⁷

What to do: ask whether your baby’s follow-up is being tracked by corrected age, and if they were very preterm, ask whether a developmental follow-up clinic is available in your area. Prematurity is a reason to watch more closely, not a reason to wait longer.

What might be behind a motor delay, and what each one changes

Most motor delay turns out to be normal variation. The rest is worth naming, because what is behind a delay changes what happens next.

Normal variation
The most common answer by a wide margin. What it changes: nothing except reassurance — but reassurance from an assessment, not from waiting.
Prematurity
Milestones judged from corrected age, as above. What it changes: the comparison you are making. Correct the age first, then decide whether there is a delay at all.
Low muscle tone
A baby who feels floppy, slips through your hands when lifted, or props to sit. What it changes: physical therapy is usually the first referral, and the underlying cause is worth investigating separately.
Cerebral palsy
Suspected where there is asymmetry, unusual movement patterns, stiffness, or early hand preference. What it changes: this is the one where speed matters most — earlier identification means earlier intervention, so asymmetry is always worth raising promptly.
Developmental coordination disorder
Usually identified later, when coordination demands rise at school. What it changes: the referral is typically occupational therapy, and the target is daily function rather than the milestone itself.
Genetic and metabolic conditions
Uncommon, and usually accompanied by findings in other systems. What it changes: your pediatrician decides whether the wider picture warrants genetics or neurology input.
Reduced opportunity to practice
Limited floor time genuinely affects motor practice, and a lot of modern baby equipment reduces it. What it changes: this one you can act on today — see the next section.
Vision
Motor development depends on vision, and reduced vision can look like motor delay. What it changes: a vision check is quick, cheap and easy to overlook. Ask for one.

What helps at home, and what to skip

None of this substitutes for an assessment if you are concerned. Doing both is entirely reasonable, and the home changes cost nothing while you wait.

Tummy time, in short frequent sessions

A systematic review of 16 studies covering 4,237 infants across 8 countries found tummy time positively associated with gross motor and total development, and with the ability to move while prone, supine, crawling and rolling.⁵ The same review found the association indeterminate for walking, standing and sitting, so this is support for movement practice generally rather than a shortcut to any one milestone.⁵

What to do: short and frequent beats long and resented. A few minutes several times a day, on the floor, starting from the early weeks. Lying chest-to-chest with your baby on you counts.

Floor time, and less time in equipment

Time in seats, bouncers and walkers is time not spent practicing the movements that build motor skills. Infant walkers are also a documented injury source: an estimated 230,676 children under 15 months were treated in US emergency departments for walker-related injuries between 1990 and 2014, 90.6% of them head or neck injuries, and 74.1% caused by falling down stairs while in the walker.⁶

What to do: a firm flat surface and space to move does more than any device sold to help. If you use a seat or carrier, use it for transport rather than for play.

Set the environment up to require movement

Toys just out of reach, so getting to them is the activity.
Barefoot where it is safe — feet give a lot of the feedback balance is built from.
Let them work at it. Some struggle is how a skill is built. Stepping in at the first sign of effort removes the practice.
Follow their lead rather than drilling a milestone before the skills underneath it are there. Standing a baby who cannot yet sit does not bring walking closer.
Vary the position across the day — on the tummy, on the back, on the side, supported sitting — rather than long stretches in any one.

What physical therapy for a motor delay actually involves

Parents are often referred without being told what the referral leads to, which makes it easy to put off.

The assessment is a standardized motor measure, observation of how your child moves rather than only what they achieve, a history, and usually some hands-on examination of tone and range. Expect it to describe a profile rather than deliver a verdict.

Sessions look like play, because play is how a child practices at this age. What differs from play at home is that the therapist is grading the difficulty deliberately — setting up the task so the child can just about do it, which is where skills are built.

The home program is the active ingredient. An hour a week with a therapist is not what changes a motor skill; what changes it is the short daily practice they set up for you to do in between. Ask for it in writing, and ask what it should look like when it is working.

Our guides to physical therapy for developmental delays, occupational therapy for developmental delays and speech therapy for developmental delays cover what each discipline does, and our cost and insurance guides cover what is likely to be covered. To find someone directly, search for a physical therapist or browse by state.

What to ask for at childcare or preschool

A child working on motor skills spends more waking hours in childcare than in therapy, so the setting matters.

Floor time rather than seat time, and ask specifically how much of the day is spent in equipment
A named person who knows what your child is working on this month
The home program run there too, if the therapist agrees — it is usually a few minutes
Positioning during floor play, so a child who props to sit is not left propped for an hour
Being told what they see, since staff watch your child move alongside a room full of others their age

From age three this can sit in an IEP through the school district. Our resources for teachers and questions to ask guide are written to be handed over.

How to get an assessment, and what it costs

Under three — early intervention. Every US state runs an early intervention program under Part C of IDEA.⁴ You can refer your own child: no doctor’s referral, no cost, regardless of income or insurance. This is the single most useful thing on this page, and many families wait months for a referral they could have made themselves in an afternoon.

Three and over — your school district, which must evaluate children who may need services. Request it in writing to start the timeline.

Your pediatrician can assess, rule out medical causes, and refer. Standardized screening is recommended at the 9-, 18- and 30-month visits, with special attention again at the 4- to 5-year visit before school entry, and a concern raised at any visit should lead to screening or a direct referral.³

What an evaluation involves: a standardized motor assessment, observation, a developmental history, and usually a conversation about daily routines. It is not a test your child can fail, and a result of “within normal limits” is a genuinely useful outcome rather than a wasted appointment.

Frequently Asked Questions

When should my baby be walking?

Most children walk independently somewhere between 12 and 18 months, with wide variation. Not walking by around 18 months is worth raising with your doctor, and the 18-month well-child visit already includes a standardized developmental screen, so it is a natural point to ask.

How do I get my child assessed for a motor delay?

Under three, contact your state's early intervention program. You can refer your own child, no doctor's referral is needed and the evaluation is free regardless of income or insurance. Three and over, request an evaluation from your school district in writing, which starts the legal timeline. Your pediatrician can also assess, rule out medical causes and refer, and the two routes run in parallel rather than in sequence.

Does time in a walker or bouncer help my baby learn to walk?

No. Time spent in seats, walkers and bouncers is time not spent practicing the movements that build motor skills, and floor time does more. Infant walkers also carry real injury risk: an estimated 230,676 children under 15 months were treated in US emergency departments for walker-related injuries between 1990 and 2014, most of them head or neck injuries, and nearly three quarters caused by falling down stairs in the walker.

Is it a problem if my baby skips crawling?

Not in itself. Some children bottom-shuffle, roll, or go straight to walking. What matters more is that they are moving around somehow and still gaining new skills. A child who is not moving around in any way by around 12 months is a different question and is worth raising.

My child was walking and has stopped. What should I do?

Contact your doctor promptly. Loss of a previously acquired skill is investigated differently from delay and should not be monitored at home, whatever your child's age.

My baby uses one hand much more than the other. Is that normal?

A clear hand preference before around 12 months is not typical and is worth raising. Consistent asymmetry is one of the more useful early signs, and it is one of the things a clinician will specifically look for. A short video of your child reaching for a toy placed directly in front of them is often more useful than describing it.

How do I count milestones for a premature baby?

Use corrected age until around two years: subtract the number of weeks early from your baby's actual age. A nine-month-old born eight weeks early has a corrected age of seven months and should be compared against seven-month expectations. Not correcting is the most common reason a preterm baby appears delayed when they are developing as expected.

Does tummy time actually help motor development?

The evidence supports it for movement generally. A systematic review of 16 studies covering 4,237 infants found tummy time positively associated with gross motor and total development and with moving while prone, supine, crawling and rolling. The same review found the association indeterminate for walking, standing and sitting, so it helps with movement practice rather than delivering any single milestone.

Should I wait and see if my child catches up?

Waiting is the thing the current milestone guidance was rewritten to discourage. The expert group that revised the CDC checklists in 2022 stated that one of its goals was to clarify when most children reach a milestone in order to discourage a wait-and-see approach, and built the lists from milestones that at least 75% of children achieve by the listed age. An assessment that finds nothing is a useful result, and it costs nothing under early intervention.

How much does an early intervention evaluation cost?

Nothing. Evaluation under IDEA Part C is free regardless of income or insurance, and you do not need a physician referral to request one. Services that follow may be charged on a sliding scale in some states, but the evaluation itself is not.

What is the difference between a motor delay and cerebral palsy?

A motor delay describes a child reaching movement milestones later than most; cerebral palsy is a specific condition affecting movement and posture, usually suspected where there is asymmetry, unusual movement patterns, stiffness, or an early hand preference alongside the delay. Only an assessment can distinguish them, which is why asymmetry in particular is worth raising promptly.

What does physical therapy for a motor delay involve?

A standardized motor assessment and observation of how your child moves, then sessions that look like play, because play is how a child practices at this age. The therapist grades the difficulty so the task sits just at the edge of what your child can do. The home program matters more than the session itself: an hour a week is not what changes a motor skill, the short daily practice in between is.

Sources

Zubler JM, Wiggins LD, Macias MM, Whitaker TM, Shaw JS, Squires JK, et al. Evidence-informed milestones for developmental surveillance tools. Pediatrics. 2022;149(3):e2021052138. PMID 35132439. The working group set out to “clarify when most children can be expected to reach a milestone (to discourage a wait-and-see approach)” and used milestones most children (≥75%) would be expected to achieve by specific health supervision visit ages. Revision produced a 26.4% reduction and 40.9% replacement of previous CDC milestones; of the retained milestones transferred to different ages, 67.7% moved to older ages.
Centers for Disease Control and Prevention. Learn the Signs. Act Early. — developmental milestone checklists, revised 2022. cdc.gov/act-early/milestones. Checked August 29, 2026.
Lipkin PH, Macias MM; Council on Children with Disabilities, Section on Developmental and Behavioral Pediatrics. Promoting optimal development: identifying infants and young children with developmental disorders through developmental surveillance and screening. Pediatrics. 2020;145(1):e20193449. PMID 31843861. Standardized screening tests are recommended at the 9-, 18- and 30-month visits, with special attention to surveillance at the 4- to 5-year visit before school entry. “Developmental concerns elicited on surveillance at any visit should be followed by standardized developmental screening testing or direct referral to intervention and specialty medical care.”
Individuals with Disabilities Education Act, Part C — Early Intervention Program for Infants and Toddlers with Disabilities. sites.ed.gov/idea. Checked August 29, 2026.
Hewitt L, Kerr E, Stanley RM, Okely AD. Tummy time and infant health outcomes: a systematic review. Pediatrics. 2020;145(6):e20192168. PMID 32371428. Sixteen articles, 4,237 participants, 8 countries. Tummy time was positively associated with gross motor and total development, a reduction in BMI-z score, prevention of brachycephaly, and the ability to move while prone, supine, crawling and rolling. The association was indeterminate for social and cognitive domains, plagiocephaly, walking, standing and sitting.
Sims A, Chounthirath T, Yang J, Hodges NL, Smith GA. Infant walker-related injuries in the United States. Pediatrics. 2018;142(4):e20174332. PMID 30224365. An estimated 230,676 children under 15 months were treated in US emergency departments from 1990 to 2014. Most sustained head or neck injuries (90.6%) and 74.1% were injured by falling down the stairs in an infant walker; of those admitted (4.5%), 37.8% had a skull fracture.
Spittle A, Orton J, Anderson PJ, Boyd R, Doyle LW, et al. Early developmental intervention programmes provided post hospital discharge to prevent motor and cognitive impairment in preterm infants. Cochrane Database of Systematic Reviews. 2024;2(2):CD005495. PMID 38348930. Forty-four studies, 5,051 randomly assigned participants. Programs “probably improve cognitive and motor outcomes during infancy (low-certainty evidence) while, at preschool age, intervention is shown to improve cognitive outcomes (high-certainty evidence)”, with considerable heterogeneity between studies.

Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. It is not a substitute for evaluation by a qualified clinician who knows your child. If your child has lost skills they previously had, contact their doctor promptly.

Delayed Motor Milestones: What's Typical and When to Ask

Key takeaways

Contact your doctor promptly if your child has lost a skill

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Frequently Asked Questions