What is Hypoxic-ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is a type of brain injury, it occurs when both oxygen and blood supply to a baby’s brain is restricted or interrupted during childbirth (perinatal asphyxia) which causes brain cells to die after short periods.

Hypoxic means not enough oxygen. Ischemic means not enough blood flow. Encephalopathy means brain disorder.

HIE may develop during pregnancy or labor and delivery. It is also possible postnatal. 

Some children will experience only mild or moderate effects from HIE. Others have severe and permanent disabilities. Developmental delay, cerebral palsy,; epilepsy or cognitive impairment are all common.

When the blood or oxygen supply to the brain is interrupted, the rest of the body may not be getting the oxygen it needs. As a result, there may be damage to organs, such as the heart, liver, kidneys and bowels. These organs usually return to normal function. The length of time the brain was without oxygen usually determines the severity of the damage.

Causes of HIE

Problems that can cause HIE during pregnancy include:

  • Problems with blood flow to the placenta
  • Preeclampsia
  • Maternal diabetes with vascular disease
  • Congenital fetal infections
  • Drug or alcohol abuse
  • Severe fetal anemia
  • Heart disease

Potential causes of HIE during labor and delivery can include:

  • Umbilical cord problems
  • Abruption of the placenta 
  • Rupture of the uterus
  • Excessive bleeding from the placenta
  • Abnormal fetal position, such as the breech 
  • Prolonged late stages of labor
  • Very low blood pressure in the mother

Problems after delivery can include:

  • Severe prematurity
  • Severe lung or heart disease
  • Serious infections
  • Trauma to the brain or skull
  • Very low blood pressure in the baby
  • Respiratory failure or cardiac arrest

Hypoxic-ischemic Encephalopathy Symptoms

Symptoms of HIE vary based on the severity and extent of the brain injury. What areas of the brain were affected also impacts the symptoms. 

  • Floppy 
  • Unreactive to sights or sounds or stronger reaction to stimulation than a healthy newborn
  • Abnormal movements or seizures
  • Have feeding problems due to weak muscles in their mouth and throat
  • Have a weak cry
  • Show signs of organ dysfunction, especially of the heart, lungs, kidneys, liver and blood


HIE may be suspected if there was fetal distress or low heart rate during labor and delivery, or if the baby needed help with breathing or low heart rate after delivery.

A neurologist examines the baby, who will be monitored by an electroencephalogram for seizures and signs of brain dysfunction and undergo neuroimaging tests, such as magnetic resonance imaging (MRI), to check for signs of brain injury.

Treatment of Hypoxic-ischemic Encephalopathy

Brain Cooling

Infants born with HIE get a brain cooling treatment. Research has shown that when the brain is cooled just a few degrees below normal body temperature soon after birth, it can stop the death of brain cells and reduce the amount of damage.

In addition to the cooling treatment, your baby may receive therapies to support any organs that have been affected by HIE. This may include:

  • Supporting the heart 
  • Maintaining healthy blood pressure
  • Sustaining kidney and liver function
  • Mechanical ventilation (breathing tube) 
  • Medications for seizures

There are treatments that help the child as they age. If milestones aren’t met and new symptoms are discovered, the care plan changes. A combination of approaches, including medical, physical and occupational therapies can be beneficial.

Devices like the Trexo gait training system help children walk, when they previously wouldn’t have been able to.

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