Newborn Jitteriness: What's Normal And What's Not?

Jitteriness in newborns is characterised by recurrent tremors, which are involuntary, rhythmic, oscillatory movements of equal amplitude. It is a common condition, with up to two-thirds of healthy newborns exhibiting fine tremors in the first few days of life. In most cases, these extra movements are completely normal and harmless, and babies tend to outgrow them by 1-2 months old. However, in some cases, jitteriness can be a sign of an underlying condition, such as hypoglycaemia, hypocalcaemia, sepsis, hypoxic ischemic encephalopathy, intracranial haemorrhage, hypothermia, hyperthyroidism, or drug withdrawal. Therefore, while jitteriness is often benign, it is important to monitor newborns for any other symptoms that may indicate a more serious issue.

Jitteriness is an involuntary movement that is frequent in newborns

Jitteriness is a common condition in newborns, often presenting after the first few hours of life. It is characterised by involuntary, rhythmic, oscillatory movements of equal amplitude, which can be described as either fine or coarse. Fine tremors are of high frequency and low amplitude, while coarse tremors are of low frequency and high amplitude. Jitteriness can be benign or pathological.

In newborns, the pathways that carry signals from the brain to other parts of the body are not yet fully developed, causing jerky and twitchy movements. As the baby's nervous system matures, these movements will become more fluid, usually by around 1 to 2 months old. Jitteriness is often accompanied by other signs of central nervous system excitation, such as hypermotility, hypertonicity, and an ease of being startled.

Jitteriness may be caused by a variety of pre-, peri-, and postnatal factors, and it is the nature and treatability of these that are the major determinants of the ultimate prognosis. For example, coarse tremors are probably more often abnormal than fine tremors and may indicate the later development of a choreiform syndrome. Benign jitteriness can occur in healthy neonates during the first 2 weeks of life and is usually a rhythmic tremor of high frequency and low amplitude, involving the chin and extremities. It is stimulus-sensitive and exacerbated by crying, with normal neurological findings and associated with normal development and neurological outcome.

The evaluation of a jittery infant must be individualised, and management should be aimed at reversing any remediable causes. If a newborn is jittery when not crying, it could be abnormal, and they should be given something to suck on, as normal trembling should stop with sucking. If the jitters get worse or occur when the baby is calm, a doctor should be consulted.

Jitteriness is often accompanied by other signs of central nervous system excitation

Jitteriness in newborns is often accompanied by other signs of central nervous system excitation, such as hypertonicity, hypoglycemia, hypocalcemia, sepsis, hypoxic ischemic encephalopathy, intracranial hemorrhage, hypothermia, hyperthyroid state, and drug withdrawal. These signs can indicate an underlying pathology that requires specific investigations and treatment.

Hypertonia, for example, involves increased muscle tone and can interfere with the infant's ability to feed. Hypoglycemia, or low blood sugar, can cause lethargy and a lack of interest in feeding, while coarse tremors may indicate intracranial pathology such as hypoxic ischemic encephalopathy or intracranial hemorrhage.

In addition to these signs, jittery newborns may also exhibit decreased visual attention and be more difficult to console compared to non-jittery infants. This can impact mother-newborn bonding and may require the implementation of consoling interventions and techniques to improve visual attention.

It is important to differentiate jitteriness from other involuntary rhythmical movements such as myoclonus and seizures. Jitteriness is typically stimulus-sensitive and can be stopped by gentle passive flexion and restraint of the affected limb. It is not usually associated with abnormal eye movements or gaze. On the other hand, seizures may be accompanied by abnormal ocular phenomena, autonomic changes, and inability to suppress the affected body part.

Jitteriness can be caused by a variety of pre-, peri-, and postnatal factors

Jitteriness in newborns is usually a benign condition, but it can be caused by a variety of pre-, peri-, and postnatal factors.

Pre-natal factors

Pre-natal factors that can cause jitteriness include maternal drug use, vitamin deficiencies, and genetic conditions. For example, newborns can experience jitteriness and tremors if their mothers used opioids, selective serotonin reuptake inhibitors (SSRIs), or other prescription or illicit drugs during pregnancy. Additionally, vitamin D deficiency in breastfeeding mothers can lead to persistent jitteriness or chin tremors in their newborns, especially if they have darker skin and live in northern climates. In terms of genetics, hyperekplexia, also known as the "startle disease," is a rare disorder characterised by muscle rigidity, nocturnal myoclonus, and an exaggerated startle reaction to stimuli. This condition is inherited in an autosomal dominant fashion and is linked to a defect on chromosome 5q33-35.

Peri-natal factors

Peri-natal factors that can cause jitteriness include premature rupture of membranes, maternal intra-amniotic infection, colonisation with Group B Streptococcus (GBS), and preterm delivery. Additionally, newborns may exhibit jitteriness due to the immaturity of their nervous systems, which can result in jerky and twitchy movements that usually resolve by 1 to 2 months of age.

Post-natal factors

Post-natal factors that can cause jitteriness include hypoglycaemia, hypocalcaemia, sepsis, hypoxic ischemic encephalopathy, intracranial haemorrhage, hypothermia, hyperthyroidism, and drug withdrawal. For example, neonatal abstinence syndrome, resulting from the sudden discontinuation of fetal exposure to substances, can lead to jitteriness and seizures.

While most cases of jitteriness are benign and resolve within the first few weeks of life, it is important to monitor newborns for any persistent or abnormal jitteriness, as it can be a sign of an underlying medical condition that requires treatment.

Jitteriness can be benign or pathological

Jitteriness in newborns can be benign or pathological.

Benign Jitteriness

Benign jitteriness is a common condition in newborns, typically presenting after the first few hours of life and resolving within the first few months. It is characterised by a rhythmic tremor of high frequency and low amplitude, involving the chin and extremities. It is stimulus-sensitive and exacerbated by crying, with normal neurological findings and associated with normal development and neurological outcome. Benign jitteriness may be caused by an immature nervous system, caffeine in breast milk, or the baby's natural development of fine motor skills.

Pathological Jitteriness

Pathological jitteriness, on the other hand, may indicate an underlying medical condition or pathology. It can be caused by various pre-, peri-, and postnatal factors, including:

• Hypoglycaemia
• Hypocalcaemia
• Sepsis
• Hypoxic ischemic encephalopathy
• Intracranial haemorrhage
• Hypothermia
• Hyperthyroidism
• Drug withdrawal
• Vitamin D deficiency
• Neonatal abstinence syndrome

Additionally, jitteriness may be a sign of seizures or neonatal sepsis, usually accompanied by respiratory distress, heart rate changes, and temperature instability.

Jittery newborns tend to have decreased visual attention and are more difficult to console

Jitteriness is a common condition in newborns, and it typically presents after the first few hours of life. It is characterised by involuntary, rhythmic, oscillatory movements of equal amplitude, which can be described as either fine or coarse. Fine tremors are of high frequency and low amplitude, while coarse tremors are the opposite. Jitteriness is often accompanied by other signs of central nervous system excitation, such as hypermotility, hypertonicity, and an ease of being startled.

It is important to note that while jitteriness is usually benign, it can sometimes be a sign of an underlying condition. For example, excessive tremors and jitteriness have been observed in newborns whose mothers were prescribed opiates or selective serotonin reuptake inhibitors during pregnancy. Additionally, maternal abuse of illicit substances such as marijuana, inhaled volatile substances, and cocaine can cause a withdrawal syndrome in newborns, characterised by coarse tremors. Other causes of jitteriness include hypoglycaemia, hypocalcaemia, sepsis, hypoxic ischemic encephalopathy, intracranial haemorrhage, hypothermia, hyperthyroidism, and vitamin D deficiency.

If you are concerned about your newborn's jitteriness, it is recommended to consult with a healthcare professional, especially if your newborn exhibits other signs of illness or has a history of perinatal complications.

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