Is My Baby Behind? 7 Signs a Pediatric Physical Therapist Looks For
Updated: Oct 16
One of the most common questions I hear from parents is:
“Is my baby behind?”
It’s an understandable question. During the first year, it can feel like everyone is watching the calendar.
Should my baby be rolling already? Why aren’t they sitting yet? My friend’s baby is crawling. Should mine be doing that, too? When will my baby walk?
Milestone ages can be helpful. But as a pediatric physical therapist, I’m looking at more than whether a baby checks off a skill by a particular month.
I’m also looking at how your baby moves.
Are they using both sides of their body? Are everyday movements getting easier? Are they trying new ways to reach toys, change positions, and explore?
There is room for variation in development. Moving differently or learning a skill later than another baby does not automatically mean something is wrong.
Still, some patterns deserve a closer look. Here are seven things I pay attention to.
The Quick AnswerTalk with your pediatrician if you notice persistent differences between the two sides of your baby’s body, unusually stiff or floppy movement, missed milestones, or difficulty making progress. A pediatric physical therapist can help assess movement concerns. If your baby loses a skill they previously had, contact their pediatrician promptly rather than waiting for the next routine visit. [1] You do not need to know what is causing a concern before asking for help. |
1. Your Baby Strongly Favors One Side
Babies do not need to move perfectly evenly every moment.
They might reach for a toy with one hand or discover how to roll in one direction before figuring out the other.
What catches my attention is a strong, persistent pattern. For example:
Their head is almost always turned toward the same side.
They consistently reach with one hand while the other does much less.
One arm or leg seems to do most of the work.
They repeatedly move around one side while avoiding the other.
A persistent head tilt or turning preference can be related to torticollis, a condition that may involve tightness in a neck muscle. It deserves a closer look because there can also be other causes. [2]
During an evaluation, I want to see what happens when toys, sounds, or people catch your baby’s attention on either side. Can they comfortably look, reach, and move both ways?
You do not need to count every reach. Bring up a difference that you keep noticing.
2. Tummy Time Isn’t Getting Easier
Some babies have very strong opinions about tummy time.
Disliking it, by itself, does not tell me whether a baby has a movement difficulty. I want to know what they can do in that position and how it is changing.
Maybe your baby can look up a little longer than before. Maybe they are starting to lean on their forearms or push their chest farther off the floor. Those small changes count.
By 6 months, the CDC includes pushing up through straight arms during tummy time among its movement milestones. [3]
If tummy time continues to feel very difficult, or your baby is struggling to lift their head or use their arms, ask for guidance. You do not have to keep pushing through an activity that feels frustrating for both of you.
Tummy time should happen while your baby is awake and supervised. Continue placing your baby on their back for sleep. [4]
3. Your Baby Feels Unusually Stiff or Floppy
Sometimes parents notice this before they have the words to describe it.
“My baby feels tense all the time.”
“They’re hard to bend when I’m getting them dressed.”
“They seem to melt into me when I pick them up.”
Unusual stiffness or floppiness is worth discussing with your pediatrician, particularly when it makes head control, sitting, or other movement difficult. [1]
You may hear a provider use the term muscle tone. It describes the background tension in muscles and is one part of a movement assessment.
You do not need to figure out your baby’s muscle tone at home. Tell your provider what you notice and when it happens. Those everyday observations help guide the evaluation.
4. Your Baby Hasn’t Reached an Expected Motor Milestone
Milestone charts are useful conversation starters. They cannot explain your baby’s whole development on their own.
The CDC lists skills that most children, meaning at least 75%, can do by a given age. Examples include:
By 6 months: rolling from tummy to back. [3]
By 9 months: sitting without support and getting into a sitting position. [5]
By 15 months: taking a few steps independently. [6]
By 18 months: walking without holding on to a person or object. [7]
The CDC milestones are helpful reference points, but there are times when I’d recommend taking a closer look before a baby reaches those ages. These are the ages I might recommend checking in with a pediatric physical therapist, so we can better understand how your baby is moving and whether a little support would help:
Not rolling by 7 months
Not sitting independently by 9 months
Not moving across the floor in any way by 11 months
Not walking independently by 16 months
For example, if your child is not walking around 16 months, I would want to hear more about their standing, cruising, and attempts at independent steps. The fact that walking appears on the 18-month checklist is not a reason to postpone a concern.
If your child is missing a milestone, bring it up with their pediatrician. Missing one does not establish a diagnosis, but it is a reason to discuss whether screening or an evaluation would help. You do not need to wait until the next age on the chart
If your baby was born prematurely, use their corrected age when discussing early milestones. This accounts for how early they were born and is generally used through the first two years. Your pediatrician can help you work it out. [8
5. Your Baby Isn’t Finding New Ways to Move Around
Parents often ask whether their baby needs to crawl on hands and knees.
Babies can use several ways to get around. Some belly crawl, some scoot, and some combine movement patterns. A different crawling style does not automatically mean a delay. Using both sides of the body and making progress still matter. [9]
I’m interested in the steps leading toward independent movement, too.
Is your baby reaching farther for a toy? Turning to look behind them? Trying to get out of sitting? Experimenting with moving toward something they want?
Those attempts give me information, even before they result in a trip across the room.
If a baby is around 10 to 11 months and has no way to move across the floor, I would recommend a conversation about their overall progress. That is a suggested check-in point, not a universal crawling deadline.
During an evaluation, I would also look at their ability to change positions, use both sides, and explore comfortably.
6. Your Baby Consistently Avoids Putting Weight Through Their Legs
This does not mean your baby should be standing independently before they are ready.
I’m talking about what happens when an older baby is supported upright. Do their feet meet the surface? Can their legs help support them? Do they consistently pull their feet away or seem unable to take weight?
Difficulty standing even with support during the later part of the first year is worth discussing with your pediatrician. [10]
During a PT evaluation, I look at how this fits with the baby’s other movements. I also consider their comfort, strength, flexibility, and foot position.
One moment with tucked-up legs does not explain the whole picture. A pattern you see repeatedly is more useful.
You do not need to force your baby’s feet down or repeatedly test them. Describe what you are seeing and ask for guidance.
7. Something About Your Baby’s Movement Keeps Catching Your Attention
Sometimes your concern does not fit neatly into a milestone chart.
Maybe your baby repeatedly avoids a position. Perhaps one movement seems much harder than everything else they do. Or you keep noticing something that is difficult to put into words.
You can bring that up.
Parents spend hours watching their babies reach, wiggle, play, and explore. Your observations are a valuable part of understanding their development. The American Academy of Pediatrics encourages parents to speak up about movement concerns. [1]
You might say:
“I’ve noticed they always do this on the same side.”
“They seem uncomfortable whenever we try this position.”
“They haven’t been able to do this lately, even though they could before.”
You do not need the right clinical term to start a useful conversation.
What Matters More Than Comparing Your Baby to Another Baby?
It is hard not to compare.
You see another baby crawling at the library. Your friend sends a video of first steps. A baby the same age appears in your feed doing something yours has not tried yet.
When that happens, come back to your own baby.
What is getting easier? What are they trying now that they were not trying before? What still seems difficult?
Progress can be small. Holding a position longer, reaching a little farther, or needing less help can all be useful things to notice.
You do not need to turn playtime into a daily assessment. These are observations you can share alongside milestone questions at your baby’s appointments.
What Happens During a Pediatric PT Evaluation?
An evaluation gives us time to look beyond a checklist.
I’ll ask about your concerns, your baby’s history, and what everyday play looks like. Then I’ll watch how your baby moves in positions appropriate for their age.
Depending on the concern, I may look at head control, strength, flexibility, balance, use of both sides, and how your baby gets from one position to another.
We can also talk about what is going well and which activities feel difficult at home.
The goal is to help you understand your baby’s movement and what, if any, support would be useful.
Sometimes that means therapy. Sometimes it means a few practical suggestions and a plan to check progress. Sometimes it means recommending further medical assessment.
You should leave with a clearer understanding of the next step.
When Should I Ask for Help?
Bring up a missed milestone or a persistent movement concern with your pediatrician. You can ask whether a developmental screening, pediatric PT evaluation, or Early Intervention referral would be appropriate. [3,5]
If your child has lost a skill they previously used, contact their pediatrician promptly. Losing a skill deserves attention even if other parts of development seem to be going well. [1,5]
Asking for help does not mean you have decided something is wrong.
It means you noticed something and want to understand it.
Frequently Asked Questions
Does reaching a milestone later than another baby mean my baby is delayed?
No. Comparing two babies cannot tell you whether either has a delay. Milestone timing, movement patterns, medical history, and progress all contribute to the assessment.
Does my baby have to crawl on hands and knees?
Some babies use other ways to move around. What matters is how they use their body and whether their movement and independence are progressing. Persistent one-sided movement or difficulty exploring deserves a conversation. [9]
When should I ask about sitting?
If your baby is not sitting without support by 9 months, discuss it with their pediatrician. Getting into sitting independently is also on the CDC’s 9-month checklist. Use corrected age if your baby was born prematurely. [5,8]
Should I wait until 18 months to ask about walking?
No. The CDC lists a few independent steps at 15 months and walking without support at 18 months. If your child is missing those skills, or you have concerns earlier, bring them up. [6,7]
What if I’m unsure whether something is worth mentioning?
Mention it. You do not need to prove there is a problem before asking a question.
Want More Practical Baby & Toddler Development Information?
Want More Practical Baby & Toddler Development Information?
Watch the full video that goes with this article, and follow Dr. Cyndi on YouTube, Facebook, and Instagram for more pediatric physical therapy and developmental education.
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About the Author
Cyndi Stedman, PT, DPT, is a pediatric physical therapist with over 17 years of experience supporting infants and toddlers. Through Early Intervention and home-based therapy, she has helped more than 1,000 families support their child’s development. Through Starting Point, she shares clear, practical guidance to help parents feel more confident supporting their child as they learn to move and grow.
References
American Academy of Pediatrics. Is Your Baby’s Physical Development on Track?
American Academy of Pediatrics. Head Tilt (Torticollis).
Centers for Disease Control and Prevention. Milestones by 6 Months.
American Academy of Pediatrics. Back to Sleep, Tummy to Play.
Centers for Disease Control and Prevention. Milestones by 9 Months.
Centers for Disease Control and Prevention. Milestones by 15 Months.
Centers for Disease Control and Prevention. Milestones by 18 Months.
American Academy of Pediatrics. Your Preemie’s Growth & Developmental Milestones.
American Academy of Pediatrics. Movement Milestones in Babies 8 to 12 Months Old.
American Academy of Pediatrics. Developmental Milestones: 12 Months.
This article is for general educational purposes only and is not intended to diagnose or treat any child or replace individualized medical or physical therapy advice. Reading this information does not establish a physical therapist-patient relationship. If you have concerns about your child's development, discuss them with your child's pediatrician or an appropriately licensed healthcare professional.
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