Babies can, however, have seizures, so it’s important to understand the difference between normal baby shakes and a more serious issue. Here we look at some common causes of baby shaking, and how to know when to be concerned.
Fine Motor Skills
Different parts of the body tend to twitch at different developmental stages. For example, during the neonatal period (the first 28 days of life), twitching of the head and extremities prepare babies for holding up their heads while twitching of the wrists and fingers in older babies may be part of the development of fine motor skills.
Immature Nervous System
In newborns, the pathways that carry the signals from the brain to the parts of the body aren’t yet fully developed, causing jerky and twitchy movements. As the baby’s nervous system matures, these movements will become more fluid.
The Startle (Moro) Reflex
If a baby is suddenly surprised by a loud noise or other environmental stimulus, you might notice an involuntary movement in which the baby extends their arms, legs, and fingers and arches their back for a few seconds. This is called the Moro reflex, or startle reflex, and is common up until the ages of 3 to 6 months.
Caffeine in Breast Milk
If you’re breastfeeding and you drink a lot of caffeinated beverages such as coffee or soda, it may cause the baby to twitch or jitter. While a little caffeine (up to 300mg, or about two to three cups of coffee) isn’t a problem, large amounts can pass to your baby and build up in their body.
Sleeping or Waking Up
Shaky and twitchy movements are also likely to occur when a baby is falling asleep or waking up. What you are seeing is likely a benign condition known as sleep myoclonus, also known as nocturnal myoclonus, and it usually occurs at the moment of dropping off to sleep. External stimuli such as noise, movement, or light can also cause these movements. Sleep myoclonus usually resolves within a year and there are no inherent consequences or reasons for concern.
Diaper Changes
If shaking movements occur every time you change their diaper, it might simply be your baby’s way of telling you that they don’t like having their diaper changed.
Hunger
Moving their arms and legs all around can be one of the signs that your baby is hungry. Crying, which can also create shaking, trembling, or stiffening of the body, is also a late sign of hunger.
Additional Reasons
There are other reasons for baby tremors, including being cold, as well as having low blood sugar. Other signs of low blood sugar, also called hypoglycemia, can include a blue tint to skin or lips, lethargy, and/or lack of interest in feeding. If you suspect your baby might be suffering from low blood sugar, be sure to reach out to their pediatrician or healthcare provider.
Signs of Seizures in Newborns
Seizures in newborns are different from seizures that occur in older children and adults. In general, the following signs may indicate your infant is experiencing a seizure:
Movements and behaviors that are not typical of children of the same ageRepeated episodes that are identical in both features and durationEpisodes that are not brought on by changes in posture or activityNoticeable change in the baby’s facial expression, breathing, and heart rateMovements that are rhythmic and may occur on only one side of the body, or are symmetric (for example, both arms do the same thing at the same time)Shaking or jerking that cannot be stopped (if an infant’s arm is jerking and you can stop it by gently holding their arm, then it probably isn’t a seizure; with a seizure, you would expect the jerking to continue as you held their arm)
Keep in mind that when a baby first begins having seizures, they may be otherwise fine, but over time, you would expect some other symptoms or problems with their development if they were having frequent seizures or spasms.
A Word From Verywell
The first time you notice your baby shaking while they’re crying or twitching in their sleep can be nerve-wracking. Try to remember that these movements are very common among infants as babies figure out their bodies and environment. Of course, if you suspect seizures or are concerned about shaky movements, don’t hesitate to call your pediatrician to double check. It is often helpful to record the suspicious activity if you can and bring the video to your pediatrician to view. The doctor can put your fears to rest and/or recommend the proper treatment if it’s indeed more than normal baby movements.
