Baby Not Using One Arm or Hand
The short answer
If your baby consistently avoids using one arm or hand, it deserves evaluation. Before 18 months, babies should use both hands roughly equally - strong hand preference before this age can indicate a concern with the less-used side. Possible causes include brachial plexus injury (Erb's palsy) from birth, nursemaid's elbow, fracture, or neurological differences. Early identification leads to better outcomes with therapy.
By Age
What to expect by age
A baby who does not move one arm from birth may have a brachial plexus injury (damage to the nerves that control the arm), which can happen during a difficult delivery. The affected arm may be limp, held in an unusual position, or have a weaker grip. Most brachial plexus injuries improve significantly with physical therapy within the first 3-6 months. Early evaluation and intervention are important.
At this age, babies should be reaching for toys and bringing hands to midline using both arms. If one arm is consistently less active, it could indicate a milder brachial plexus injury, muscle tone difference, or early signs of cerebral palsy (hemiplegia). Your pediatrician will check arm strength, range of motion, reflexes, and whether both hands open and grasp equally. Early physical and occupational therapy can be very beneficial.
Hand preference normally develops between 18 months and 3 years. A strong preference for one hand before 12-18 months, or a complete avoidance of using the other hand, is not typical and should be evaluated. A sudden change where a toddler stops using an arm they previously used normally could indicate nursemaid's elbow, a fracture, or a neurological event.
What Should You Do?
When to take action
- A slight preference for one hand after 18 months of age
- Temporarily not using an arm that was recently vaccinated (injection site soreness)
- Using both arms but one slightly less skillfully in the early stages of a new motor task
- Your baby consistently reaches with only one hand and ignores the other
- One hand stays fisted while the other opens and grasps normally
- You notice a difference in arm strength or movement between sides
- Your baby was noted to have a difficult delivery and one arm seems weaker
- Your baby has not moved one arm since birth
- Your toddler suddenly stops using an arm they previously used normally
- There is visible swelling, deformity, or severe pain in the arm
- Loss of arm use is accompanied by other new neurological symptoms like facial drooping or difficulty walking
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 Prefers One Hand Too Early
True hand preference should not develop until at least 18 months to 2 years of age. If your baby consistently uses only one hand and ignores or avoids using the other before 18 months, it may indicate that the less-used hand or arm has reduced strength or coordination. This is different from a slight preference and is worth discussing with your pediatrician.
Nursemaid's Elbow (Pulled Elbow) in Baby or Toddler
Nursemaid's elbow is the most common orthopedic injury in children under 5. It happens when a ligament in the elbow slips out of place, usually after a pulling or swinging motion on the arm. The child suddenly stops using the affected arm, holding it still at their side with the palm turned inward. It is not a dislocation or fracture, and it is easily fixed by a doctor with a quick, gentle maneuver. Recovery is immediate - most children use the arm normally within minutes of reduction.
Baby Not Grasping Objects
Babies develop voluntary grasping gradually over the first several months. Most babies begin reaching for objects around 3 to 4 months and develop a reliable grasp by 5 to 6 months. If your baby is under 4 months and not yet grabbing things, this is completely expected and normal.
Baby or Toddler Body Odor - When Is It Normal?
Babies and toddlers can develop body odor from several benign causes: sour milk caught in skin folds, sweating, diaper area odor, strong-smelling foods in the diet, and certain medications or vitamins. True body odor (like adult BO from apocrine glands) should not occur before puberty. If your baby or young toddler has a persistent unusual body odor that is not explained by skin folds, diaper, or diet, it could indicate a metabolic condition, infection, or foreign body (especially in the nose or vaginal area). Unusual persistent odor warrants a doctor visit.
Baby Born with Teeth - Natal Teeth
Natal teeth (teeth present at birth) occur in about 1 in 2,000-3,000 births. In most cases, these are actual primary (baby) teeth that erupted early, not extra teeth. Most natal teeth are the lower front incisors. While natal teeth can sometimes cause breastfeeding difficulties or have a risk of becoming loose and being a choking hazard, many can be left in place and monitored. The decision to keep or remove a natal tooth depends on how firmly it is attached and whether it is causing problems.