Low Muscle Tone in Arms (Hypotonia)
The short answer
Low muscle tone in the arms means your baby's arms may feel floppy or offer less resistance than expected when you move them. While some babies naturally have lower muscle tone that improves with time and practice, significant or persistent low tone in the arms can affect reaching, grasping, and tummy time skills. Your pediatrician can assess whether your baby's tone is within the normal range or whether a referral for physical or occupational therapy would be helpful.
By Age
What to expect by age
Newborns typically hold their arms in a flexed position close to their body and offer some resistance when you gently extend their limbs. A baby with low arm tone may let their arms rest loosely at their sides and offer little resistance when moved. Some degree of variation is normal, and premature babies often have lower tone initially. If your baby's arms seem significantly floppy and they have difficulty with feeding or show very little arm movement, bring this to your pediatrician's attention.
By this age, babies should be reaching for objects, bringing their hands together at midline, and starting to bear weight on their forearms during tummy time. Low arm tone can make these activities more difficult. You may notice your baby tires quickly during tummy time, has trouble reaching for and holding toys, or seems to use their arms less than expected. Physical therapy can be very effective at this stage to build strength.
Babies are now transferring objects between hands, feeding themselves finger foods, and bearing weight through their arms for crawling. Low arm tone may slow progress in these areas. Your baby may crawl with a modified pattern or prefer to scoot rather than bear weight through their arms. An evaluation can help determine the best approach to support your baby's upper body development.
Toddlers with low arm tone may have difficulty with activities like throwing a ball, climbing playground equipment, pushing riding toys, or using utensils. They may tire more quickly during activities that require arm strength. Occupational therapy can help build functional arm strength through play-based activities. Many children with mild low tone make excellent progress with consistent support.
What Should You Do?
When to take action
- Your baby has slightly lower tone than other babies but is meeting developmental milestones within the expected timeframes.
- Your premature baby has lower arm tone that is gradually improving as they grow.
- Your baby's arms feel a bit relaxed, but they are actively reaching for objects, bearing weight during tummy time, and using their hands appropriately for their age.
- There is a family history of being very flexible or "double-jointed," and your baby is otherwise developing well.
- Your baby's arms feel notably floppy and they have difficulty bearing weight on their arms during tummy time by 4 months.
- Your baby seems to avoid using their arms for reaching, grasping, or weight bearing, and this is affecting their development.
- You notice that your baby's arm tone is significantly different on one side compared to the other.
- Your baby's arms have become progressively floppier over time rather than getting stronger, or your baby has lost arm movement they previously had.
- Your baby has severely floppy arms combined with difficulty feeding, breathing problems, or overall low alertness.
Sources
Related Resources
Related Physical Concerns
My Baby Seems to Use One Side More Than the Other
Babies should use both sides of their body fairly equally during the first 18 months of life. While slight preferences can be normal, a consistent pattern of favoring one side - using one arm much more than the other, crawling with one leg dragging, or turning the head predominantly one way - should always be discussed with your pediatrician. Early identification of asymmetry leads to the best outcomes.
My Baby Curls Their Toes
Toe curling is very common in babies and is usually caused by the plantar grasp reflex, which is a normal newborn reflex that causes toes to curl when the sole of the foot is touched. This reflex typically fades by 9-12 months. Occasional toe curling during standing or walking is also normal as babies figure out their balance. Persistent, tight toe curling past 12 months may warrant a mention to your pediatrician.
My Baby Favors One Leg
Babies should use both legs roughly equally when kicking, crawling, and eventually walking. If your baby consistently favors one leg or seems to avoid using the other, it is worth having your pediatrician take a look. The cause is often something simple and treatable, like a minor hip or muscle issue, but early evaluation helps ensure the best outcome.
My Baby Gets Hiccups a Lot
Hiccups are extremely common in babies, especially newborns, and are almost always completely harmless. They happen because your baby's diaphragm is still developing and gets a little jumpy when their tiny stomach fills up or air gets swallowed. Most babies outgrow frequent hiccupping by 6-9 months.
My Baby Has Jerky Movements
Newborns and young babies often have jerky, uncoordinated movements because their nervous systems are still developing. What looks like random flailing is actually your baby learning how their body works. These movements typically become smoother and more controlled by 3-4 months as motor skills mature.
Baby Not Bearing Weight on Arms
Bearing weight on the arms is a gradual skill that develops during the first 6 months. Babies first prop up on their forearms around 2 to 4 months, then progress to pushing up on extended arms by 5 to 6 months. Regular tummy time is the best way to build this strength, even if your baby protests at first.