Child & Family Development Child & Family Development

March 21, 2013

Why is My Baby Only Using One Side of Their Body?

Is your baby only using one side of their body? On average, favoritism of the left or right hand is established between the ages of 18 and 24 months. Hand preference usually occurs between ages 2 and 4. By kindergarten, most children have established a dominant hand. If your child shows an overwhelming preference to one hand before this specified period, there may be reason for concern.

There are several warning signs for disuse of one side to be aware of:

· If your child has one limb that appears to be dramatically stronger.

· If one hand is fisted or if a thumb is always held in the palm of the hand.

· If there is a significant difference in the skill of grasping between the two hands.

· If your child never reaches with one hand and immediately transfers a toy to the other hand if a toy is placed in the nonpreferred hand.

· If your child always has their weight shifted to one side of the body in sitting and standing positions.

· If your child sits persistently with their knees to one side coupled with scooting in sitting sideways and using only one arm.

¬∑  If you notice that your child appears to neglect one side of the body or does not notice objects placed on the nonpreferred side.

¬∑  If stiffness and floppiness is noted in one arm or leg only.

¬∑  If your child does not bear weight on one arm or leg.

¬∑  If while crawling, one elbow is significantly and persistently more bent than the other elbow when bearing weight.

¬∑  If your child is consistently on the tiptoe of only one foot.

Things to Rule Out:


· Cerebral Palsy:

o  A neurological dysfunction can result from damage to the brain in the areas that control movement.  In cerebral palsy, this damage occurs before, during, or shortly after birth and may cause significant stiffness or floppiness on one side of the body.


· Brachial Plexus injury:

o Injury to the brachial plexus can cause weakness or numbness in one arm.


· Leg length discrepancy:

o When a child has one leg shorter than the other, they can compensate by walking on the tiptoe of the shorter leg.



Physical development is unique to each child. There is a huge variability in the range of which normal gross motor skills are met. However, a significant difference between the use of one side of the body and the other is a definite red flag. If you have any concerns or notice any of the above mentioned warning signs, a Physical Therapy evaluation can determine if your child can benefit from intervention.   




Developmental Disabilities. American Academy of Pediatrics. Retrieved from