Hypoxic-ischaemic encephalopathy (HIE)

Find out about hypoxic-ischaemic encephalopathy (HIE), signs and treatment.

What is hypoxic-ischaemic encephalopathy (HIE)?

Hypoxic-ischaemic encephalopathy (HIE) may be diagnosed if your baby’s brain does not receive enough oxygen and/or blood flow around the time of birth. You might hear this being referred to as ‘asphyxia’, ‘birth asphyxia’ or ‘perinatal asphyxia’. Low oxygen and/or blood flow to a baby’s brain happens most commonly before or during birth, but it can also happen shortly after birth.

HIE affects the brain, but the effects of low oxygen or blood flow can also cause problems in the lungs, liver, heart, bowel and kidneys.

When diagnosed, HIE is graded as mild, moderate or severe. Where HIE is graded as moderate or severe, it can result in long-term disability and in some cases can sadly result in death. We have more information about making critical care decisions, palliative care and bereavement, and links to some more sources of support further down this page.

If your baby has been diagnosed with HIE, you are likely to have lots of questions about what caused this, what treatment your baby will need and how the condition may affect them in the long term. Talk to the staff looking after your baby if you have questions or need something explaining again. They will be happy to help.

What causes HIE?

It is not always possible to know what causes HIE. It can be caused by complications around the time of birth, such as the following:

  • The placenta coming away from the uterus wall too soon (placental abruption).
  • Tearing of the uterus (uterine rupture).
  • Having an usually long labour (prolonged labour).
  • Your baby’s shoulders getting stuck behind the pubic bone during delivery (shoulder dystocia).

If you are unsure what may have caused HIE, talk to the team looking after your baby for more information.

What are the signs of HIE?

HIE is usually diagnosed in the first few days after birth. A doctor will make the diagnosis based on certain signs, which are different depending on how severe it is.

Doctors will look for some of the following signs in your baby:

  • Being hyper-alert - they may appear over-awake, even with little sleep.
  • Being irritable – they may start to dislike noise, touch and light.
  • Being overly sleepy.
  • Being floppy or stiff.
  • Having unusual movements or seizures.
  • Having pauses in breathing (apnoea).
  • A reduced level of awareness or responsiveness.

When diagnosed, HIE is graded as mild, moderate or severe. The grade of HIE will determine the treatment that is recommended for your baby.

What tests might my baby have?

If your baby's healthcare team are concerned about or diagnose HIE in your baby, they may arrange further tests.

These might include (but are not limited to) the following:

  • Cerebral Function Monitoring (CFM) – CFM uses sensors to record brain activity. It is used to show the early effects of HIE on your baby’s brain, and can be also used to decide if your baby needs therapeutic hypothermia (cooling) treatment.
  • Head ultrasound scan (cranial ultrasound) – A head ultrasound scan is used to look at images of your baby’s brain. It can be used to show problems such as bleeding, stroke, or swelling.
  • MRI scan – An MRI scan uses magnetism to build up a very detailed picture of areas of your baby’s brain. It is used to see if any damage has been done to your baby’s brain. It is usually performed after cooling treatment (see below).

What treatment is available for HIE?

Most babies with mild HIE recover quickly. If your baby has mild HIE, doctors will monitor them closely to check that they are stable and do not need any more treatment.

If your baby has moderate to severe HIE, there is a risk of death or long-lasting damage to the brain.

To reduce this risk, babies with moderate or severe HIE are likely to receive a treatment called therapeutic hypothermia or cooling, which needs to be started within the first 6 hours after birth. A special cooling mattress is used to lower the baby’s temperature to between 33 and 34 degrees centigrade for 72 hours. The mattress is filled with fluid that can be cooled or warmed according to your baby’s needs.

Your baby’s temperature will be monitored closely to ensure that it stays at the right temperature, and cooling will usually be continued for 72 hours before rewarming. Your baby will be rewarmed over a period of 12 hours. During the cooling period, the team will also closely monitor your baby’s heart rate and blood pressure, perform blood tests and use a CFM. They will also monitor your baby’s medication and give pain relief if needed.

Some parents are worried that they will not be able to hold or have skin-to-skin with their baby during cooling treatment. You may be able to hold or touch your baby during cooling, but this depends on how unwell your baby is and how much equipment is attached to them. Talk to your baby’s doctor or nurse if you have any questions or concerns.

During this time, you can also help your baby by expressing breastmilk and talking and reading to your baby.

Research shows that cooling can benefit some babies with moderate or severe HIE who are born after 36 weeks, and reduces the risk of long-term disability. We understand that knowing your baby is going to have this treatment can be frightening.

You might want to ask the team looking after your baby the following questions:

  • What does cooling involve?
  • What are the benefits of cooling?
  • Are there any risks of cooling, and how likely are they to happen?
  • What care will my baby need after the treatment?
  • What might happen if my baby doesn’t have the treatment?
  • How will treatment affect my baby’s ongoing development?

It is always important to talk to the team looking after your baby if you have any concerns or questions. They are there to help.

What are the long-term effects of HIE?

While some babies with HIE recover fully and have no long-term problems, others may develop difficulties that need help and support from healthcare professionals, such as physiotherapists or speech and language therapists.

If your baby has had cooling treatment, you will meet with your baby’s doctor to talk about your baby’s MRI scan results. They will also talk to you about your baby’s behaviour and progress. This will be used to make a plan for further assessment and follow-up. The amount of appointments your baby will have will depend on their needs.

All babies who have been affected by HIE will need their development monitored closely, particularly during the first 2 years of their life.

When your baby is between 18 months and 2 years old, a healthcare professional will look at your baby’s progress in the following areas of their development:

  • Motor (your baby’s ability to move around and hold and grasp objects).
  • Sensory (your baby’s sight, touch, taste, smell and hearing).
  • Language (your baby’s ability to communicate and understand language).
  • Cognition (how your baby learns to think and reason).

This assessment can help to provide a better understanding of how your child is developing and can help to answer any concerns that you may have.

Some babies will develop cerebral palsy, which is a physical condition that affects movement, posture and co-ordination . Some babies may develop problems with their eyesight and hearing, or have learning or behavioural difficulties. Some babies will go on to develop epilepsy, which is a condition that affects the brain and causes seizures.

Knowing that your baby could have long-term problems as a result of their HIE can be frightening and overwhelming at first, but there is support available. At the bottom of this page we have listed some organisations and sources of support that can help.

Sadly, some babies will die of HIE. We have more information about making critical care decisions, palliative care and bereavement, and link to some more sources of support further down this page.

Where can I get more help and support?

Having a baby in intensive or special care can be a stressful experience. Having a baby who is unwell can make you feel out of control of your situation. Some parents feel grief or loss as they lose or let go of hopes and plans they had. Having a baby with HIE is always unexpected.

How you feel and process what has happened to you might be different to others who face these challenges. Feeling this way is very common.

If you are unsure about any part of your baby’s diagnosis, treatment or care, the staff on the unit will help you in any way they can. It is okay to ask again if you need information repeated or made clearer. The team will understand and want to support you.

We have included some links to charities and organisations who can provide more support. Social media websites such as Facebook may also be able to provide information about local support groups and charities where you can talk to other parents who have a baby with HIE. Your unit may also be able to provide you with this information. If you need someone to talk to, you can also contact us on hello@bliss.org.uk or arrange a video call with one of our volunteers.

  • Peeps HIE charity – Provides support to parents affected by HIE, and raises awareness.
  • The Birth Trauma Association – Provides support to women who have had a traumatic birth experience.
  • The Rainbow Trust – Provides emotional and practical support to families who have a child with a life-threatening or terminal illness.
  • Sands - A charity that supports anyone affected by the death of a baby.
  • Scope - A charity that supports disabled people and their families through practical information and support, particularly at the time of diagnosis.
  • Together for Short Lives – A charity for children with life-threatening and life-limiting conditions.
  • Epilepsy Action – Provides advice and support to anyone affected by epilepsy.