Newborn babies have many unique behaviors that can be surprising to new parents. A newborn shaking or trembling can be alarming and is often characterized by fine, rapid tremors of the hands, arms, or legs. These movements are a common and usually normal phenomenon in the first few weeks of a baby’s life.
The Immature Nervous System
The primary reason for newborn jitteriness is the baby’s developing nervous system. This complex network of nerves and the brain is not yet fully mature. The pathways transmitting signals from the brain to muscles are still being refined, which can result in jerky or uncoordinated movements.
This neurological immaturity is also responsible for reflexes unique to newborns, such as the Moro reflex, often called the startle reflex. When a baby is surprised by a loud noise or sudden movement, they may fling their arms out, extend their legs, and then quickly pull them back in. This response can sometimes be mistaken for jitteriness.
As the nervous system continues to develop, these movements become smoother. The myelination process, where a fatty sheath grows around nerve fibers to speed up signal transmission, is still underway. These normal newborn jitters and reflexes will decrease and disappear within the first two months as the baby’s systems mature.
Potential Triggers of Jitteriness
Beyond a developing nervous system, specific situations can trigger or amplify jitteriness. One of the most common triggers is hunger. A baby’s cry, often a late sign of hunger, can be accompanied by shaking as they signal their need for food, which is linked to a temporary drop in blood sugar between feedings.
Low blood sugar can cause tremors, and other signs may include a bluish tint to the skin or lips and a lack of interest in feeding. Overstimulation is another frequent cause. A newborn’s brain can be overwhelmed by too much noise or bright lights, which can lead to trembling as the nervous system struggles to process the information.
Certain substances can also play a role. If a breastfeeding mother consumes a significant amount of caffeine, it can pass into her breast milk and cause the baby to be more jittery. Even a diaper change can be enough stimulus to induce a brief episode of shaking.
Distinguishing Jitters from Seizures
For many parents, the primary fear is that these tremors could be a seizure. There are clear ways to distinguish between benign newborn jitters and a seizure. The clearest difference is the response to touch; jitteriness can be stopped by gently holding the trembling limb.
Seizure activity, however, will continue even when the affected body part is held. The nature of the movement itself also provides clues. Jittery movements are fine, rapid tremors that are rhythmic, while a seizure involves jerky movements that are less rhythmic and more forceful.
Jitters often affect both sides of the body symmetrically, while seizures may be confined to one side or involve asymmetrical movements. Another important distinction involves associated signs. Jitteriness is just the movement itself.
Seizures in newborns are frequently accompanied by other concerning symptoms. These can include abnormal eye movements, such as staring, rapid blinking, or the eyes rolling back. Changes in breathing patterns or skin color may also occur during a seizure but are not features of simple jitteriness.
When to Seek Medical Advice
While most jitteriness is normal, certain signs should prompt a conversation with a healthcare provider. You should seek medical advice if you notice any of the following:
- The movements cannot be stopped by gently holding the baby’s limb.
- The trembling is accompanied by abnormal eye movements, such as sustained staring or rolling.
- Changes in your baby’s breathing or skin color occur during an episode.
- A sudden high-pitched cry that is unusual for your baby, persistent poor feeding, or extreme lethargy.
- The jitteriness seems to be worsening over time or continues beyond the first few months of life.
Recording a video of the episode can be very helpful for the doctor to see exactly what is happening.