Hypoxic-Ischemic Encephalopathy (HIE)

Hypoxic-ischemic encephalopathy (HIE) is a permanent neonatal brain injury caused by oxygen deprivation and/or limited blood flow to the brain at or near the time of birth. When this happens, brain cells die off in a cascade reaction, causing widespread damage. Hypoxic-ischemic encephalopathy is preventable in the vast majority of cases. Moreover, doctors may limit the long-term damage caused by HIE by performing therapeutic hypothermia (also known as ‘brain cooling’). If doctors suspect that a baby has HIE, it is mandatory that they provide therapeutic hypothermia. Other terms for HIE are perinatal asphyxia, birth asphyxia, intrapartum asphyxia, and neonatal encephalopathy.

Hypoxic Ischemic Encephalopathy (HIE)

What is hypoxic-ischemic encephalopathy (HIE)?

(HIE) Hypoxic Ischemic Encephalopathy Definition | Infographic

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Hypoxic-ischemic encephalopathy is a newborn brain injury caused by oxygen deprivation to the brain around the time of delivery. HIE is estimated to occur in about 1.5 per 1,000 live births, although this estimate may be imprecise (1). Neonatal encephalopathy is a broad term used to describe any disturbed neurological function in a newborn baby. HIE is a common type of neonatal encephalopathy. It accounts for 23% of neonatal deaths worldwide, and babies that survive may develop cerebral palsy (CP), intellectual and developmental disabilities (I/DDs), epilepsy, and many other associated conditions (2).

For babies with HIE, the seriousness of the brain damage (and the likelihood of subsequent disabilities) depends on the following conditions:

  • The severity of the oxygen deprivation
  • The length of time that the baby was deprived of oxygen
  • The condition of the baby prior to the oxygen deprivation
  • The management of the baby by the medical team after the oxygen-depriving event occurred

Breaking down ‘hypoxic-ischemic encephalopathy’: what is a hypoxic-ischemic brain injury?

A hypoxic-ischemic brain injury is a brain injury caused by a lack of oxygen (hypoxia) and a lack of blood flow (ischemia) to the brain. There are multiple causes of HIE. In older children and adults, HIE may result from anything that causes a lack of oxygen to the brain including a heart attack, stroke, trauma to the head, carbon monoxide poisoning, drug overdose, or near drowning (3, 4). In babies, HIE can be due to problems during pregnancy, labor, and delivery, or shortly after birth. See “Causes of hypoxic-ischemic encephalopathy (HIE) and birth asphyxia” for more information.

Frequently asked question: how long can a baby survive without oxygen?

The questions about how long an unborn baby can survive without oxygen is a complex one. First, there is the distinction between survival with adverse health effects (such as brain damage) versus survival without adverse health effects. Second, it depends on the severity of the oxygen deprivation. If the baby is receiving no or very little oxygen, they could die or become seriously brain injured in a matter of minutes. Based on animal models, brain injury occurs when there is lack of oxygen over 10 to 25 minutes. Often, the safest and quickest way to save a baby that is being deprived of oxygen is via emergency C-section.

Guidelines from the American College of Obstetricians and Gynecologists (ACOG) state that an emergency C-section must be performed within 30 minutes from the time it is determined to be necessary. However, there are many situations in which this is not fast enough, and it is against standard of care to delay an emergency C-section more than is absolutely necessary. In many  cases, the decision-to-delivery interval should only be a few minutes (5).

Frequently asked question: can hypoxia cause seizures?

Yes, hypoxia can cause seizures. When the brain is deprived of oxygen, it means that brain cells are deprived of one of the key components they need to function. When these cells die, the complex connections that help different parts of the brain communicate are disrupted. This can result in seizures, which are abnormal electrical discharges in the brain.

Visualizing HIE and neonatal brain injury

HIE and diminished blood flow

Hypoxic Ischemic Encephalopathy (HIE), Birth Asphyxia, Neonatal Encephalopathy

Terms and definitions for HIE

Understanding HIE - Hypoxic Ischemic Encephalopathy Core Terms - Infographic

Causes of hypoxic-ischemic encephalopathy (HIE) and birth asphyxia

A number of complications and medical mistakes can cause or increase the risk of hypoxic-ischemic encephalopathy. These include, among others:

For more detailed information about the causes and risk factors for hypoxic-ischemic encephalopathy, please click here.

Signs and symptoms of hypoxic-ischemic encephalopathy

Signs of hypoxic-ischemic encephalopathy (HIE) at birth may include the following:

  • Breathing problems/need for resuscitation of the newborn
  • Low APGAR Scores. An APGAR score assesses the overall health of a newborn over the first few minutes of life. It assigns scores to conditions such as the baby’s skin color and complexion, pulse rate, reflexes, muscle tone, and breathing.
  • Seizures shortly after birth
  • Difficulty feeding, including the inability to latch, suck, or swallow
  • Absence of other neonatal reflexes (e.g. the baby fails to respond to loud sounds or movement, does not grasp onto objects such as a finger, etc.)
  • Profound metabolic or mixed acidemia in an umbilical artery blood sample (the baby’s blood is acidic/has a low ph)
  • Hypotonia (low muscle tone/limpness)
  • Multiple organ problems (e.g., the involvement of the lungs, liver, heart, intestines)
  • Coma/altered consciousness

Diagnosing hypoxic-ischemic encephalopathy

Hypoxic-ischemic encephalopathy is confirmed through tests and neuroimaging studies, including the following:

  • CT scans
  • PET scans
  • MRIs
  • Blood glucose tests
  • Umbilical cord and arterial blood gas tests
  • EEGs
  • Ultrasounds

In order to perform these tests, doctors must first suspect that a difficult or traumatic birth has occurred. If delivery was traumatic, oxygen-depriving complications occurred, or signs for HIE are present in the baby, medical professionals should begin the diagnostic process.

It is important to note that a newborn may have sustained a hypoxic-ischemic injury, but not show signs of it until later in childhood, when they exhibit delayed developmental milestones (including problems with motor skills, growth, cognitive function, etc).

HIE can cause numerous health conditions, including:

Treatment for hypoxic-ischemic encephalopathy (birth asphyxia)

HIE treatment before the advent of therapeutic hypothermia

Traditionally, babies with HIE have been treated with supportive care to limit brain damage and prevent further injury. Specifically, HIE treatment has included conventional measures such as ventilation, NICU care, controlling or preventing seizures, maintaining blood glucose and blood pressure, minimizing cerebral swelling, and receiving care from specialty physicians.

Treating HIE today: therapeutic hypothermia (brain cooling)

More recently, a newer treatment called therapeutic hypothermia (also known as brain cooling) has been introduced specifically for the treatment of hypoxic-ischemic encephalopathy. Therapeutic hypothermia has shown promising results in improving the outcome of babies with HIE by reducing the severity of neurological injury.

The treatment consists of lowering a newborn’s body temperature to around 91-95 degrees Fahrenheit for a period of about 72 hours. Lowering the baby’s temperature slows the metabolic rate, allowing cells to recover over a longer period of time. This avoids further damage that can occur if normal oxygenation or blood flow is restored too quickly to injured cells. Once hypoxic-ischemic encephalopathy is diagnosed, it is critical that therapeutic hypothermia begins as soon as possible (it is most effective if begun within the first six hours after injury), as long as all indications for the treatment are met (6). Failure to perform therapeutic hypothermia on a newborn baby who is eligible and in need of the treatment is an instance of medical malpractice.

Therapeutic Hypothermia - Body Cooling for Babies with Hypoxic-Ischemic Encephalopathy (HIE)

Preventing hypoxic-ischemic encephalopathy

Prevention of birth asphyxia and HIE boils down to two major factors:

  1. Closely monitoring the mother and baby so that fetal distress or impending distress is recognized
  2. Quickly delivering the baby when fetal distress or impending distress are present.

During pregnancy, the mother and baby should have regular prenatal tests to help ensure fetal health. If the pregnancy is high risk, more frequent prenatal testing is required and the mother should be referred to a maternal-fetal specialist. As soon as the mother is admitted to the labor and delivery unit, a fetal heart monitor should be attached to her body and the baby’s heart rate should be continuously monitored.

The point of a fetal heart monitor is to alert the medical team of fetal distress. If a baby is experiencing a lack of oxygen to the brain, this will result in nonreassuring heart tracings on the fetal monitor. When nonreassuring tracings occur, the medical team may try resuscitative maneuvers which are aimed at increasing blood flow and oxygen to the baby. These maneuvers may include IV fluids, giving oxygen to the mother, or changing the mother’s position. However, there is no guarantee that resuscitative maneuvers will relieve fetal distress. In fact, distress caused by certain obstetrical conditions, such as a complete umbilical cord compression or complete placental abruption may not be affected by in-utero resuscitation; babies experiencing these conditions must be delivered within a matter of minutes.

When fetal distress occurs or is impending (i.e. a pregnancy/delivery complication has been identified), the medical team should make preparations for a possible emergency C-section while doing in-utero resuscitation maneuvers. It is very important to have skilled members of the healthcare team involved in labor and delivery. It takes skill to interpret fetal heart tracings, and these tracings are often the only indication that a baby is experiencing birth asphyxia and HIE. The team also must be well-coordinated so that preparations and execution of a C-section delivery are fast. A delay in performing a necessary C-section can cause hypoxic-ischemic encephalopathy and permanent brain damage in the baby.

How do you pronounce hypoxic-ischemic encephalopathy?

Video: our Michigan hypoxic-ischemic encephalopathy lawyers discuss HIE

In this video, hypoxic-ischemic encephalopathy lawyers Jesse Reiter and Rebecca Walsh discuss the causes of and treatments for HIE.  Negligence by the medical team is often the cause of HIE and birth asphyxia.

Legal help for children with HIE and birth injuries

Hypoxic-ischemic encephalopathy cases require specific, extensive knowledge of both law and medicine. For the best case outcomes, it’s critical to find an attorney and a law firm that focus specifically on HIE cases. At ABC Law Centers, our hypoxic-ischemic encephalopathy lawyers have been focusing their careers on birth injury and HIE cases, and they consistently secure multi-million dollar settlements for their clients.

Our office is in Michigan, but we handle cases throughout the United States. Our birth injury team is also equipped to handle cases involving military medical malpractice and federally-funded clinics.

Phil Review of Reiter and Walsh

Contact us today to begin your free case review. Free of charge and obligations, we will answer your legal questions, determine the negligent party, and inform you of your legal options. Moreover, you pay nothing throughout the entire legal process unless we win or favorably settle your case. Our team is available to speak with you to set up an appointment in any of the following ways:

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Related reading from our hypoxic-ischemic encephalopathy lawyers


  1. Kurinczuk, J. J., White-Koning, M., & Badawi, N. (2010). Epidemiology of neonatal encephalopathy and hypoxic–ischaemic encephalopathy. Early human development, 86(6), 329-338.
  2. What is the global prevalence of hypoxic-ischemic encephalopathy (HIE)? (2018, July 26). Retrieved November 15, 2018, from https://www.medscape.com/answers/973501-106461/what-is-the-global-prevalence-of-hypoxic-ischemic-encephalopathy-hie
  3. Heinz, U. E., & Rollnik, J. D. (2015). Outcome and prognosis of hypoxic brain damage patients undergoing neurological early rehabilitation. BMC research notes, 8(1), 243.
  4. (n.d.). Retrieved November 15, 2018, from https://www.uptodate.com/contents/hypoxic-ischemic-brain-injury-in-adults-evaluation-and-prognosis
  5. Reiter, J., P.C. (2008, July). Emergency Cesarean Sections: When 30 Minutes Is Not Fast Enough. BTLG Newsletter.
  6. (n.d.). Retrieved November 15, 2018, from https://www.uptodate.com/contents/clinical-features-diagnosis-and-treatment-of-neonatal-encephalopathy#H16