What Are the Stages of Hypoxic-Ischemic Encephalopathy (HIE)?

The moments leading up to and immediately following the birth of a child are supposed to be the joyous culmination of months of planning, waiting, and hoping. But for some families, that moment takes an unexpected turn. Instead of the reassuring cry of a newborn, there may be urgent medical responses, worried expressions, and unfamiliar terms being spoken by doctors.

A diagnosis of Hypoxic-Ischemic Encephalopathy (HIE) can leave parents reeling. It’s a serious brain injury caused by a lack of oxygen and blood flow to a baby’s brain, often during labor or delivery. By learning about the injury's classification and the stages of HIE doctors use to assess severity, you gain crucial insight into potential treatments, outcomes, and the care your child will need.

At the Brain Injury Law Center, we’ve spent nearly 50 years standing beside families affected by traumatic and birth-related brain injuries. Our mission is to help you understand what you're facing, what your options are, and how to move forward, legally and emotionally.

If you believe medical negligence may have played a role in your child’s HIE diagnosis, or if you simply want to understand your legal options, please contact us at (757) 244-7000 or fill out our online form for a free, confidential consultation. 

Understanding HIE: What Is Hypoxic-Ischemic Encephalopathy?

Hypoxic-Ischemic Encephalopathy (HIE) is a serious birth injury that can impact both premature and full-term newborns. Tragically, studies show that between 40% and 60% of infants diagnosed with HIE either pass away by the age of two or face significant long-term disabilities: 

• Hypoxic: Refers to a lack of oxygen reaching the baby’s organs, including the brain.
• Ischemic: This means "low blood flow." Blood is the vehicle that carries oxygen to every cell in the body. If blood flow is blocked or restricted, oxygen cannot get through.
• Encephalopathy: This is simply a medical term for a disease, damage, or malfunction that affects the brain.

HIE is a type of brain injury that occurs when a newborn’s brain is deprived of an adequate supply of oxygen and/or blood flow. This deprivation, usually happening right before, during, or immediately after birth, causes the death of brain cells.

An infant's brain is incredibly delicate and has a constant, urgent need for oxygen. Even a brief interruption can start a chain reaction of cellular damage that is difficult to stop. The severity of the HIE diagnosis and the long-term prognosis depend almost entirely on two factors: how long the oxygen deprivation lasted and how complete that deprivation was.

What Causes HIE? 

It is important to acknowledge that some cases of HIE may stem from unavoidable complications related to the mother's health or issues with the placenta that develop organically. These might include rare instances of fetal stroke or specific problems with the placenta's ability to transfer oxygen.

However, our focus at the Brain Injury Law Center, and the reason we have dedicated five decades to this work, is that many cases of HIE are preventable. They happen not because of a medical fluke, but because of a failure to follow the established standards of care during the most critical time: labor and delivery.

The vast majority of severe HIE cases we investigate are linked to medical missteps, oversights, or delays during the birthing process. In these cases, it is a matter of medical negligence or malpractice.

• Failure to Monitor Fetal Distress: If the monitoring strip shows a pattern that indicates distress (a change in heart rate that signals a crisis), nurses and doctors are required to act immediately. A delay of just minutes in recognizing or responding to these alarming changes can lead directly to the oxygen deprivation that causes HIE.
• Delayed Emergency C-Section: Many complications, such as the placenta separating from the uterine wall (placental abruption) or a failing heart rate, require the baby to be delivered immediately, usually via an emergency C-section, to restore their oxygen supply. A delay in deciding to perform an emergency C-section, or a delay in carrying out the surgery once the decision has been made, is one of the most common forms of negligence that results in severe HIE.
• Umbilical Cord Complications: The umbilical cord is the baby's lifeline. If the cord is wrapped tightly around the baby's neck or body, or if it slips down into the birth canal ahead of the baby and becomes compressed, the oxygen supply is instantly cut off. Medical staff must recognize these high-risk situations instantly and intervene with speed.
• Mismanaged Maternal Conditions: The medical team must properly manage maternal health issues like high blood pressure or diabetes. Poorly controlled conditions can lead to oxygen deprivation for the baby. Similarly, a failure to recognize or quickly respond to a uterine rupture can cause rapid and fatal blood and oxygen loss to the baby.

When an injury is severe, as HIE often is, the family must know the truth. Was the injury a tragic accident, or was it a preventable error? Our firm is dedicated to securing these answers for you.

Recognizing and Diagnosing HIE

HIE often becomes apparent within minutes or hours after birth.  While some symptoms are clear immediately, others develop as the newborn’s condition evolves. A fast and accurate diagnosis is critical, as early intervention can greatly influence long-term outcomes.

The delivery team watches for several key indicators that may suggest a newborn is in distress:

• Low Apgar Scores: The Apgar test is performed at 1 and 5 minutes after birth and evaluates five key functions: skin color, heart rate, reflexes, muscle tone, and breathing. A score below 7 may signal distress, and a score of 3 or lower, especially if it remains low after 5 or 10 minutes, raises concerns about oxygen deprivation.
• Need for Immediate Resuscitation: Babies with HIE may not breathe on their own or may have a very weak cry. If a newborn requires assisted ventilation or CPR shortly after birth, doctors may suspect that the brain was deprived of oxygen.
• Poor Muscle Tone: Normal newborns typically show resistance when limbs are moved and exhibit spontaneous movements. In contrast, babies with HIE may be still, weak, or unreactive.
• Abnormal Reflexes: Certain reflexes are expected at birth, such as grasping a finger placed in the palm, a startled response when the baby feels like they are falling, and the sucking reflex. When these are absent, weak, or exaggerated, it may indicate neurological issues.
• Seizures: Seizures may appear as jerky movements, twitching, lip-smacking, or even subtle eye movements. Early seizures are a strong sign of brain dysfunction or injury.
• Changes in Alertness: Babies with HIE may be unusually sleepy, difficult to wake, or entirely unresponsive.

If a baby shows any of the signs above, doctors will typically begin a series of diagnostic evaluations to determine whether HIE is present and its severity, including:

• Umbilical Cord Blood Gas Analysis: This test measures the pH of the baby’s blood right after birth. A very low pH level is a strong signal that the baby was deprived of oxygen during labor or delivery.
• Neurological Examination: A detailed physical exam allows doctors to assess the baby’s tone, reflexes, responsiveness, eye movements, and level of consciousness. Abnormal results may point to signs of brain injury.
• MRI: This is the most reliable imaging method for detecting brain damage from HIE. MRIs typically take place a few days after birth and can show both the location and extent of injury to the brain tissues.
• CT Scan: Sometimes used in urgent cases where an MRI isn't immediately available. CT scans are faster but less detailed, and may be useful in the earliest hours of life.
• EEG: Continuous EEG monitoring may be used in the NICU to evaluate ongoing brain function.

At the Brain Injury Law Center, we have spent nearly five decades supporting families affected by brain injuries, including HIE. This is not just one of the many types of cases we handle; it’s our sole focus. Our team works alongside families to help secure the financial support needed for therapy, equipment, long-term care, and peace of mind.

If you have questions about your child’s diagnosis or believe that medical negligence may have played a role, we’re here to help. Call us at (757) 244-7000 or fill out our online form for a free, private consultation.

What Are the Stages Of Hypoxic-Ischemic Encephalopathy?

HIE stages of development are divided into three categories: Stage 1 (Mild), Stage 2 (Moderate), and Stage 3 (Severe).

The staging is based on a baby’s physical symptoms, reflexes, muscle tone, and neurological exam results shortly after birth. Knowing what are the stages of HIE is vital because a child’s prognosis is closely tied to the stage they are placed in.

Stage 1: Mild HIE 

In the first stage of HIE, symptoms may seem subtle or even counterintuitive. Instead of being sleepy or unresponsive, babies with mild HIE often appear unusually alert or jittery. They may have an exaggerated startle reflex, be more sensitive to touch or sound, or display tremors. 

Feeding may be difficult due to irritability or inconsistent sucking. While muscle tone is generally close to normal, some babies might appear slightly stiff or shaky.

These symptoms typically emerge within the first few hours after birth and often resolve on their own within 24 to 48 hours.

Most babies with Stage 1 HIE recover fully without long-term effects. However, some recent research suggests that even mild cases should be followed closely, as subtle developmental or cognitive differences can emerge later in childhood. 

Stage 2: Moderate HIE

Stage 2 represents a more serious degree of brain injury and is often marked by noticeable changes in behavior and responsiveness. 

Babies in this stage tend to be very sleepy or lethargic. They may have difficulty waking, weak or absent reflexes, and poor muscle tone, meaning they appear limp or floppy when held. Seizures are a key sign of moderate HIE and often occur within the first 24 hours of life. Feeding problems are also common, especially due to a weak or absent sucking reflex.

At this stage, babies may show irregular breathing patterns, decreased responsiveness to touch or sound, and limited or absent reflexes.

These symptoms typically persist for several days to two weeks. The long-term effects of moderate HIE vary. Some children recover well with no lasting impairments, while others may face developmental delays, motor challenges, or a diagnosis of cerebral palsy (CP) later in life. 

Stage 3: Severe HIE

Stage 3 is the most serious form of HIE and typically involves widespread brain dysfunction. Babies in this stage may appear deeply unresponsive or comatose. They often do not respond to pain, sound, or light. 

Breathing may be irregular or absent, requiring mechanical ventilation. Muscle tone is profoundly reduced, and the baby may appear entirely limp. Reflexes are often absent, including essential ones like sucking, swallowing, and blinking.

Seizures may be severe, frequent, or difficult to control, sometimes appearing 24–48 hours after birth. Eye movements can be abnormal, pupils may be fixed or dilated, and vital signs may be unstable. These signs indicate serious disruption of the brain’s ability to regulate basic bodily functions.

Sadly, Stage 3 HIE carries the highest risk of long-term disability or death. Many infants who survive will experience severe cognitive and physical challenges. The risk of profound cerebral palsy, epilepsy, or other significant impairments is high. 

Knowing what are the stages of Hypoxic-Ischemic Encephalopathy is the first step toward understanding the long-term needs and legal options for your child.

Stages of Hypoxic-Ischemic Encephalopathy and Their Long-Term Effects 

The outcome for a child diagnosed with HIE is a spectrum. As we have seen, the prognosis is directly tied to the severity of the initial injury, as classified by the HIE stages of development, and how quickly effective treatment was initiated.

For families whose children were diagnosed with moderate or severe HIE (Stages 2 and 3), the effects can be life-changing and often result in lifelong medical conditions:

• Cerebral Palsy (CP): This is the most common long-term diagnosis following HIE. CP is a disorder of movement, muscle tone, or posture that is caused by damage to the developing brain. Depending on the area of the brain affected by oxygen deprivation, CP can range from mild walking difficulties to profound motor impairment requiring a wheelchair and constant assistance.
• Epilepsy/Seizure Disorders: Since the brain tissue was damaged, the child may develop chronic electrical instability that results in recurrent seizures.
• Developmental and Cognitive Delays: This can include learning difficulties, language and speech delays, memory problems, and issues with attention or executive function.
• Vision and Hearing Impairments: Damage to the occipital lobe of the brain (vision) or the areas that process sound can lead to permanent vision loss or hearing deficits.

The emotional toll of these diagnoses is immeasurable. The financial costs are equally daunting. The needs of a child with severe cerebral palsy or intellectual disabilities require specialized equipment, round-the-clock care, accessible housing, continuous therapy, and potentially a lifetime of lost parental income.

Treatment Options for HIE

When a newborn is diagnosed with HIE, quick and carefully coordinated medical care can make a lasting difference. In the hours, days, and even years that follow birth, a variety of treatments can help protect the baby’s brain, manage symptoms, and support the best possible outcome.

Therapeutic Hypothermia (Cooling Therapy)

For babies with moderate to severe HIE, cooling therapy is often the first and most urgent intervention.

Doctors gently lower the baby’s body temperature to around 92.3°F to 93.2°F using a special cooling blanket or cap. This treatment lasts for 72 hours and is designed to reduce swelling and prevent further brain cell damage during a critical window of time. Cooling therapy must begin within six hours of birth to be effective.

Cooling therapy doesn’t undo damage that has already occurred, but it can slow the secondary wave of injury. By slowing the brain’s metabolism, cooling gives the brain a better chance to heal.

Once the initial crisis has passed, care shifts to long-term management and rehabilitation, which can continue for months or even years. Every child’s needs are different, but common treatments include:

Seizure Management

Seizures are common in HIE, especially in the first few days of life. Doctors may use anti-seizure medications to prevent seizures from causing additional harm. Some babies may need long-term seizure control as they grow.

Nutritional and Feeding Support

Some babies with HIE have trouble sucking, swallowing, or coordinating breathing while feeding. A feeding tube may be used to ensure proper nutrition, especially early on. Over time, feeding therapy can help babies learn these skills as their nervous system develops.

Physical, Occupational, and Speech Therapies

These therapies are often the foundation of a child’s developmental progress:

• Physical therapy helps improve strength, coordination, and motor skills.
• Occupational therapy focuses on daily activities like grasping, playing, and dressing.
• Speech and language therapy helps with communication and, in some cases, feeding skills.

When HIE Should Never Have Happened

A diagnosis of HIE doesn't just affect your child’s brain. It shatters the future you imagined for them. The first words. The first steps. The first day of school. All the hopes you quietly carried during pregnancy may now feel uncertain, or painfully out of reach.

And when HIE was caused by medical negligence, the heartbreak is magnified by injustice. 

Beyond the emotional toll, the financial cost of caring for a child with HIE can be staggering:

• Lifelong therapy and medical equipment
• Around-the-clock care
• Home modifications
• Lost income from leaving work to become a full-time caregiver

Most families simply aren’t prepared for this level of expense. That’s why seeking legal accountability is critical.

Why Families Trust the Brain Injury Law Center

At the Brain Injury Law Center, brain injury law isn’t a side practice. It’s all we do. 

We work with top medical experts, dig into every page of the medical record, and identify exactly where the standard of care failed your child. If negligence caused this injury, we will fight to hold those responsible accountable and help secure a future where your child’s needs are fully funded for life.

If your child was diagnosed with HIE and you suspect it was preventable, call the Brain Injury Law Center today at (757) 244-7000 or fill out our online form. Your consultation is completely free and confidential