Twitching and Jitteriness in Preemies

Newborn babies twitch. They may also shake, tremble, and jerk their arms and legs around when asleep or even when awake. Full-term babies can have newborn twitching and jitteriness, but it's even more common in premature babies. These awkward movements are usually a result of a newborn's nervous system, which is still developing after birth. But sometimes, shaking and tremors can be a red flag of seizures or other problems.

How can you tell when baby jitters are normal and when to worry? Here are some causes of newborn twitching and tremors and clues for spotting the difference between normal movements and a possible seizure.

Normal Baby Twitching

When parents talk about newborn twitching, they are usually referring to small jerking movements that typically only last a few seconds. Though short, these jerking movements may happen repeatedly. You may notice these twitchy behaviors when your child is sleeping. Babies also twitch in response to being held, moved, or being startled, like when they hear a loud noise.

Jitteriness looks like fine tremors or trembling. In the first month or two of life, it's very common for babies (whether they are premature or full-term) to shake, tremble, or momentarily stiffen up when they cry. You might also notice your baby's arms, legs, or jaw quivering. Jitters stop on their own, but you can help quiet them by gently grasping and holding the body part that's trembling. You can also try giving your child a pacifier or a feeding to stop the trembling.

Natural Causes

Research has shown that up to two-thirds of newborns have tremors during their first few days of life. Some babies, especially preterm infants, can be twitchy or jittery for various reasons beyond those first days. Most newborn twitchiness or jitteriness is not cause for alarm and is likely due to one of the following common reasons.

Immature Nervous System

Newborns have an immature nervous system. The pathways that carry the signals from the brain to the parts of the body aren't yet fully developed, so their movements can appear jerky and twitchy. The jerking and twitching will become less frequent after the first few weeks of life as the baby’s nervous system matures. Preterm babies' reflexes might still appear unpredictable and jerky a few months longer until they catch up to their full-term peers.

At certain early developmental stages in both full-term and premature babies, different body parts may twitch. For example, during the neonatal period, the twitching of the head and extremities help prepare the baby for holding up their head and learning what their arms and legs can do. Then, as the child grows, the twitching of the wrists and fingers may help in the development of fine motor skills.

Normal Movements During Sleep

Parents often notice newborns twitching when they expect them to be most relaxed: during sleep. These nap time and nocturnal movements, also known as sleep myoclonus, may be related to their development, too. Increasing research suggests that sleep twitches boost babies' sensory-motor development.

During different phases of sleep, full-term babies and preemies may periodically jolt or jerk. During the rapid eye movement (REM) stage of sleep, you may notice quick eye movements along with body twitching.

Startle Reflex (Moro Reflex)

A baby will jump or twitch when they are suddenly surprised, like when they hear a loud noise. The child's whole body appears to stiffen up, then the arms and legs quickly straighten out and the hands open. The baby then pulls his arms and legs back in close to his body. The startle reflex, also known as the Moro reflex, only lasts a few seconds.

Parents will notice their babies occasionally showing a Moro reflex in the first 12 weeks of life. It usually dissipates after 6 months, when a baby can support their own head, but it might be later for preemies.

Too Much Caffeine in Breast Milk

If you're breastfeeding and you drink a lot of caffeinated beverages (such as coffee, tea, or soda), the caffeine you consume will go into your breast milk. A small amount of caffeine usually isn't a problem, but too much caffeine from your breast milk might cause your baby to become irritable, have difficulty sleeping, and begin to show signs of twitching or the jitters.

Be sure to discuss your caffeine intake with your doctor. Experts recommend breastfeeding parents have no more than 200 to 300 milligrams of caffeine per day and to consider consuming less than that if breastfeeding a preemie, whose metabolism might eliminate caffeine more slowly.

Medical Causes

There are some medical causes of trembling or shaking. If your baby is showing frequent jitteriness or tremors and you suspect any of the following, it's important to call your child's pediatrician as soon as possible.

Low Blood Sugar

One of the first signs of low blood sugar (hypoglycemia) is shaking. If a baby's blood sugar (glucose) levels drop, it can cause shaking and tremors. Low blood sugar is a common issue that preemies face, especially if the person who carried them had diabetes or preeclampsia during pregnancy. If low blood sugar is the culprit, feeding might be all it takes to normalize your baby's levels and stop the tremors.

Electrolyte Imbalances or Vitamin Deficiencies

Low sodium (hyponatremia) can cause an increase in muscle activity which looks like jerking or twitching. If your child has an electrolyte imbalance, they may need intravenous (IV) fluids. It's important to seek medical help if low sodium could be an issue with your baby.

A baby's involuntary movements can also signal a mineral deficiency, like low calcium (hypocalcemia) or low magnesium (hypomagnesemia). Shudders, shivers, or tremors can also be an early sign of low vitamin D levels in a newborn.

Drug Withdrawal

Infants born to people with substance use disorders can have tremors, twitching, and shaking in the days or weeks following birth. Some babies do not need any treatment for drug withdrawal, but it depends on the drug and the severity of the symptoms.

Is It a Seizure?

Neonatal seizures occur in 1.5% of newborns and are even more common in preterm babies. In newborns, a seizure doesn't necessarily look like extreme shaking or thrashing. It might be a repeated jerking movement of the arms or legs, or it might look like a repetitive motion of mouth and tongue or the head. A seizure might also look like a cyclical arching or stiffening up and then relaxing a part of the body.

One clue that a baby is having a seizure rather than newborn twitching or jitteriness is that parents cannot easily still or relax the shaking body part with gentle hand pressure.

When to Be Concerned

Seizures are sometimes caused by a serious medical condition such as an infection, a lack of oxygen to the brain, or a neurological problem, so it's important to call a doctor right away if you suspect one. While many preemies who have neonatal seizures will grow and develop normally, seizures still have to be treated and monitored carefully.

If you notice your baby might be experiencing the following life-threatening symptoms during a suspected seizure, it's important to call 911 or seek medical care right away:

• The baby won't wake up, isn't moving, or isn't responsive.
• Their cry seems suddenly weaker than usual
• The baby is making new grunting or moaning noises
• Blue or gray coloring is appearing around the baby's mouth, signaling breathing troubles

A Word From Verywell

The first time you notice your baby twitching in their sleep or see their chin quivering while they are crying, it can be alarming. But these behaviors are usually just a normal part of early nervous system development, especially for preemies.

Sometimes, there is a medical explanation for twitching or jitteriness, including electrolyte imbalances, mineral or vitamin deficiencies, or less commonly, neonatal seizures. If you suspect one of these reasons for your baby's twitchy or shaky behavior, don't hesitate to seek out medical help. Doctors will likely reassure you that these behaviors are normal, but if they are not, you'll be helping your baby get the care they need.