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Benign neonatal convulsions

What is a syndrome?

A syndrome is a group of signs and symptoms that, added together, suggest a particular medical condition. In epilepsy, examples of these signs and symptoms would be things like the age at which seizures begin, the type of seizures, whether the child is male or female and whether they have physical or learning disabilities, or both. The results of an electroencephalogram (EEG) are also used to help identify epilepsy syndromes.

Epilepsy Action has more information about seizure types, learning disabilities, and the EEG.

If you would like to know more about an epilepsy syndrome, please speak to your doctor. If you would like to know more about epilepsy in general, please contact Epilepsy Action.

Benign neonatal convulsions

Benign neonatal convulsions (BNC) is a relatively uncommon type of epilepsy that happens in babies and very young infants. The seizures, or convulsions, usually start between three and 14 days after the baby has been born. Because many start on the fifth day of life, they used to be called ‘fifth day fits’. The seizures affect girls and boys equally.

There are two types of BNC:
• Benign familial neonatal convulsions
• Benign non-familial (also called sporadic) neonatal convulsions

In the first type, benign familial neonatal convulsions, someone else in the family must have had similar convulsions and this is usually one of the baby’s parents. It may be hard for the parents to know whether they had convulsions as a baby, because they won’t remember themselves! Therefore, if possible, the baby’s grandparents should be asked if they can remember whether the baby’s parents had convulsions or ‘fits’ at the same age. A genetic fault that causes benign familial neonatal convulsions has been found in some genes, which are part of chromosome number 8 and also chromosome number 20.

In the second type, benign non-familial (also called ‘sporadic’) neonatal convulsions, there is no history of convulsions at a similar age in other members of the family.


The seizures can appear in different forms

  • An arm or leg stiffens and then jerks rhythmically for some seconds or up to a minute (called a clonic seizure)
  • The head turns to one side and then jerks a few times. This can be followed by a clonic seizure affecting either the right or left side of the body
  • The arms, legs or all four limbs may jerk at the same time
  • There are repeated cycling or punching movements of the legs or arms 
  • Rarely, the whole body goes stiff and then all four limbs jerk (called a ‘tonic-clonic’ seizure)

Most seizures last less than two minutes. The seizures are more likely to happen when the baby or infant is sleepy or has just woken from sleep. The babies are otherwise normal and will have been feeding and behaving normally before the seizures started. Their birth will usually have been normal.


BNC is diagnosed when the doctor takes a careful history of when the seizures started and also a careful family history. Seizures that start on the fifth to fourteenth day after birth in otherwise normal babies are important clues as to the correct diagnosis. Results of tests such as blood tests and such as computed tomography (CT) or magnetic resonance imaging (MRI) are usually normal. The EEG may be normal or show only minor abnormalities.

There are many other causes for seizures, and other epilepsy syndromes that might also start at the same age. Causes can include low levels of glucose, calcium or magnesium in the blood, serious infections such as meningitis or encephalitis or abnormalities in the brain. Because of this, it is often important for the doctor to rule out these other causes. This may include tests such as a lumbar puncture to look for meningitis or encephalitis, and a more detailed brain scan, the MRI scan.

Blood tests can also be done to look for the genetic fault called a ‘mutation’. This mutation is found in children with benign familial neonatal convulsions. This is called a mutation in the KCNQ2 and KCNQ3 genes. No genetic fault has yet been found in benign non-familial (also called sporadic) neonatal convulsions.

Epilepsy Action has more information about diagnosis.


Treatment is not always necessary because the seizures may only happen for a few weeks. However, sometimes epilepsy medicine is prescribed, particularly if the seizures continue to happen. Commonly used epilepsy medicines)
include carbamazepine (Tegretol), sodium valproate (Epilim) or much less commonly, phenobarbital. The newer drugs such as levetiracetam (Keppra) may also be effective. The medicine is usually given for six or occasionally 12 months and then slowly discontinued.

Epilepsy Action has more information of the treatment of epilepsy.

Prognosis (outlook)

In most babies or infants, the seizures usually stop after a few days, weeks, or, rarely, months. About one in 10 children who have benign familial neonatal convulsions may start having other types of seizures in late childhood or, more commonly, in adulthood. However, the risk is much lower in benign non-familial (also called sporadic) neonatal convulsions. In this group, only one or two children in every 100 will develop epilepsy in adulthood. If this happens, the seizures are usually controlled with epilepsy medicines.

Babies feed normally, behave normally and develop normally. They usually don’t have learning disabilities or need extra care/support in the future.


Contact a Family
Freephone helpline (UK only): 0808 808 3555
Website: cafamily.org.uk
Email: info@cafamily.org.uk 

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Our thanks

Epilepsy Action would like to thank:
• Dr Richard Appleton, and Dr Rachel Kneen, consultant paediatric neurologists at Alder Hey Children’s Hospital, Liverpool, UK and
• Dr Stewart Macleod, consultant paediatric neurologist at Royal Hospital for Sick Children, Glasgow, UK.
They have kindly prepared the information on this page. It is based on their own research, experience and expertise.

This information is exempt under the terms of The Information Standard.

  • Updated June 2012
    To be reviewed June 2015

Comments: read the 2 comments or add yours


This is wonderful information. I had these seizures as an infant passed down from my grandma's father and on. My daughter had them recently as an infant and was on phenobarbital until she was 8 months old. The doctors who helped us had a hard time finding resources on this rare genetic condition, so thank you for helping me find a helpful resource for the doctors we've been working with. The information seems accurate with what we experienced and seen in the 5 generations of us who started having seizures at 5 days old. Thank you!

Submitted by Amy Butler on

Hello Amy

Thanks for your comment. It’s great to know our materials help.

We also have some information about epilepsy and inheritance which may interest you.



Advice & Information Team

Submitted by Sacha-Epilepsy ... on

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