Hypoxic-ischemic encephalopathy (HIE) in newborns

How does this happen?

Brain cells need a steady supply of oxygen. Blood carries it. When either the oxygen or the blood flow drops far enough, cells start to run out of fuel.

The injury happens in two waves. The first wave is the event itself. Cells that lose fuel cannot hold their normal balance of salts and water, and some die within minutes.

The second wave is the one that matters for treatment. Hours after blood flow returns, a chemical cascade starts inside cells that survived the first wave. Over the next one to three days, many of those cells die too. This delayed wave is called secondary energy failure. ⁵

Therapeutic hypothermia works on that second wave. Lowering the body temperature slows the cascade, so more of the injured-but-alive cells recover. That is why the six-hour window exists. Once the second wave is well underway, cooling has less to work with. ¹

Different parts of the brain are hurt by different patterns. A sudden, total loss of blood flow, such as a umbilical cord prolapse or a uterine rupture, tends to injure the deep structures: the basal ganglia and the thalamus. A slower, partial loss over a longer time tends to injure the outer border zones of the brain, called the watershed areas. Radiologists read these patterns on MRI. ⁵

The two waves, drawn out

What causes it?

Two different questions get mixed together here. The first is what leads to this injury in the body. The second is whether anyone could have prevented it. They are not the same question, and the answer to the first does not settle the second.

Happens even with perfect care

Some babies develop HIE when every person in the room did everything right, and on time.

• A placental abruption can happen with no warning. The placenta tears away from the wall of the uterus and oxygen delivery drops in seconds.
• A umbilical cord prolapse can happen the moment the water breaks. There is no way to predict it and often only minutes to act.
• A uterine rupture can occur even in a well-run trial of labor after cesarean. It happens in under 1 percent of these labors. ⁶
• Infection during pregnancy, such as chorioamnionitis, can injure a baby's brain before labor even starts. ⁴
• A stroke, a clotting problem, or a genetic condition can look exactly like HIE in the first days. Professional guidance is explicit that many newborns with neonatal encephalopathy have a cause other than low oxygen during labor. ⁴

This matters for a reason beyond the medicine. Parents carry guilt about this. Nothing you ate, lifted, worried about or failed to notice caused a placental abruption.

Associated with gaps in care

These are situations where published standards say what the care team should watch for and do. A gap here does not prove anyone caused your child's injury. It points to where the medical records will have an answer.

These are the situations where published standards say what the care team should be watching for and what they should do. Finding one of these in your records does not prove that it caused your child's injury. It tells you where to look and what to ask.

• A fetal heart rate pattern that was not acted on. Standards define three categories of tracing. A Category III tracing pattern is abnormal and calls for prompt evaluation and action, which may include delivery. ⁷ Repeated late decelerations and loss of variability are the findings most often at the center of these questions. ⁸
• A delay between the decision to deliver and the delivery. Many hospitals hold themselves to a decision-to-incision time of 30 minutes for the most urgent cesareans. The chart records both times.
• oxytocin pushed too high. tachysystole means more than five contractions in 10 minutes averaged over 30 minutes. Contractions that come too close together leave the placenta less time to refill with oxygenated blood. ⁷
• A shoulder dystocia managed outside the recognized sequence. There is a defined set of maneuvers, starting with the McRoberts maneuver. ⁹
• A resuscitation that did not follow the newborn algorithm, or that was slow to escalate. ¹⁰
• Cooling not offered, or started late, in a baby who met the criteria. The six-hour window is not a suggestion. ¹
• Maternal infection not treated. Untreated Group B strep or chorioamnionitis raises the risk of newborn brain injury, and there are clear standards for screening and for antibiotics in labor. ¹¹
• Signs of trouble in the mother that were not escalated, such as severe preeclampsia or bleeding suggesting placental abruption. ¹²

Whether any of these amounts to a departure from the standard of care is not something a website can decide, and it is not something a single chart entry decides either. It takes a physician expert reading the whole record. What you can do is get the records and read them. The guide to reading your records walks through each document.

What are the signs, by age?

Signs change as a child grows. A newborn cannot show you a walking problem. Some children look fine at first and show differences months later.

At birth and the first hours

• Low Apgar score scores that stay low at 5 and 10 minutes. The score describes the baby at that moment, and by itself it does not predict the future. ¹³
• A need for help breathing at birth, from a mask, a tube, or chest compressions.
• A cord blood gas showing a low pH and a large base deficit.
• Poor tone. The baby feels floppy or, less often, stiff.
• Weak or absent reflexes, including a weak suck.

The first week

• Seizures. In newborns these often do not look like shaking. Watch for lip smacking, bicycling legs, eye deviation, or a pause in breathing. ¹⁴
• Trouble feeding, poor suck, or trouble coordinating suck and swallow.
• An abnormal level of alertness, either very sleepy or unusually irritable.
• Breathing that is irregular or that needs support.

Around 3 months

• Stiffness or floppiness that does not settle.
• Fisted hands that stay closed past 3 months.
• Poor head control when pulled to sit.
• Feeding that stays hard, or long feeds, or frequent coughing during feeds.
• Little interest in faces, or eyes that do not follow.

Around 6 months

• Not rolling over. ¹⁵
• Using one hand much more than the other. A clear hand preference before 12 months is not typical and is worth raising. ¹⁶
• Pushing back or arching when held.
• Not bringing hands together at the middle of the body.

Around 12 months

• Not sitting without help. ¹⁵
• Not pulling to stand.
• Stiff legs that cross, or toes that point down.
• No babbling, and no response to their name.

Toddler years

• Late walking, or walking on toes, or an uneven gait.
• Few words, or words that are hard to understand.
• Trouble with cups, spoons, and small objects.
• Seizures that appear or return in this period.

School age

• Learning differences, attention difficulties, and slower processing, even in children who walk and talk typically.
• Vision problems that come from the brain rather than the eye, called cortical visual impairment.
• Fatigue, because movement takes more effort than it does for other children.

How is it diagnosed?

HIE is diagnosed by putting several things together. No single test makes the diagnosis. ⁴

The examination

A doctor examines the baby and stages the encephalopathy using Sarnat staging. They look at alertness, tone, reflexes, posture, the pupils, heart rate and breathing. ³

The stage is decided in the first hours, and it can change. Ask which stage was recorded and at what time. It appears in the chart.

Blood and cord tests

A cord blood gas is drawn from the umbilical cord at birth. It shows how much acid built up in the baby's blood, which reflects the oxygen supply near the end of labor. A pH below 7.0 with a base deficit of 12 mmol/L or more is one of the findings that professional guidance associates with an acute event around the time of birth. ⁴

A normal cord gas makes an injury during labor much less likely, and that is useful information in both directions.

Brain monitoring

aEEG is a simplified brain monitor placed at the bedside. Full EEG uses more leads and is the only reliable way to tell whether a newborn is seizing, because many newborn seizures are electrical only and produce no movement you can see. ¹⁴

Imaging

MRI is the most useful scan, and timing matters. diffusion-weighted imaging shows fresh injury best in roughly the first four to five days, and it can normalize after that even though the injury is still there. A scan around days 4 to 10 shows the pattern and extent most clearly. ⁵

MR spectroscopy measures chemicals in brain tissue. A raised lactate peak in the deep gray matter is one of the strongest early predictors of later outcome. ⁵

cranial ultrasound is done first in many units because it is quick and can be done at the bedside. It is much less sensitive than MRI for this kind of injury.

The placenta

The placental pathology report can show infection, clots, or long-standing poor blood flow. It often answers questions nothing else can, because it is a record of the months before birth. Ask whether the placenta was sent to pathology. If it was not, that is worth noting.

What is the treatment?

Therapeutic hypothermia, and the six-hour window

The baby's body temperature is lowered to about 33.5 degrees Celsius for 72 hours, then warmed slowly. It is done with a cooling blanket or cap, in a NICU, with continuous monitoring.

It is offered to babies born at or near term with moderate or severe encephalopathy, and it is started within six hours of birth. ¹

In the Cochrane review of 11 trials covering 1,505 babies, cooling reduced the combined outcome of death or major disability at 18 months. ¹

Seizure treatment

Seizures are treated with medicine, usually phenobarbital first. Because many newborn seizures cannot be seen, treatment decisions are guided by EEG. ¹⁴

Supporting the rest of the body

Low oxygen affects more than the brain. The team watches the kidneys, the liver, the heart, the gut and the clotting system. Many babies are kept NPO at first and fed through an IV. Blood sugar is kept in a narrow range, because both low and high sugar make brain injury worse. ¹⁷

After the NICU

Therapy usually starts before discharge and continues at home through early intervention. Federal law entitles a child under 3 with a diagnosed condition or a delay to an evaluation at no cost to you. ¹⁸ You can refer your own child. You do not need a doctor's referral and you do not need a diagnosis.

Early, specific therapy matters. Evidence supports starting intervention as soon as a child is identified as high risk rather than waiting for a confirmed diagnosis. ¹⁶

What is the long-term outlook?

Outlook depends most on the stage and on what the MRI shows. Ranges are more useful than averages here, so this section gives ranges.

Mild, stage 1. Most babies with mild encephalopathy that resolves within 24 hours do well. Follow-up still matters, because a share of these children show learning or attention differences at school age. ⁵

Moderate, stage 2. This is the group where cooling changes the picture most. Outcomes range widely, from no lasting effects to cerebral palsy with significant needs. MRI findings in the first two weeks predict outcome better than the birth history does. ⁵

Severe, stage 3. The risk of death or major disability is high, and it stays high with cooling. Cooling improves the odds; it does not remove them. ¹

Two things are true at once. HIE is the most common single cause of cerebral palsy that begins at birth in babies born at term, and most children with cerebral palsy did not have HIE. ⁴

Ask for a clear answer to this question: what did the MRI show, and which part of the brain is affected? A radiology report that describes normal deep gray matter carries very different information from one that describes injury there.

What does daily life look like?

This section is what nobody tells you in the NICU.

Therapy load. A child with moderate effects may have physical therapy, occupational therapy and speech-language pathology weekly, sometimes more. Add travel, and it becomes a part-time job for one parent. Many families ask for therapy at home or at daycare rather than at a clinic, which the early intervention program can often do.

Feeding. Feeding is frequently the hardest part of the first year. Some children need thickened liquids, some need a G-tube. A G-tube is often described as a step backward. In practice families often describe it as the thing that ended the daily fight over food and let them enjoy their child again.

Equipment. Over the first years this can include a supportive seat, a stander, a walker, ankle-foot orthoses, a bath chair, and a wheelchair. Most are covered by insurance or Medicaid with a prescription and a therapist's letter of medical necessity.

Sleep. Many children with brain injury sleep poorly. This is real, it is common, and it is treatable. Raise it with your child's doctor rather than absorbing it.

School. From age 3 the school system takes over from early intervention through an IEP. Read the IEP guide before the first meeting, not after.

Your own life. Parents of children with disabilities have higher rates of depression, anxiety and post-traumatic stress. This is a known clinical finding, not a personal failing. ¹⁹ The parent's own health guide is on this site for a reason.

What does care cost over a lifetime?

Nobody publishes a current, condition-by-condition lifetime cost for HIE, so anyone quoting you a precise figure is estimating.

What does exist is a CDC study that estimated lifetime costs for people born in 2000 with certain conditions, in 2003 dollars. For cerebral palsy, which is the most common lasting outcome of moderate to severe HIE, the estimate was about $921,000 per person. That figure covers direct medical costs, direct non-medical costs, and lost productivity. ²⁰

Three things to hold in mind about that number:

1. It is in 2003 dollars. Medical prices have risen a great deal since.
2. It is an average across all severities. A child at GMFCS level I and a child at level V do not have similar costs.
3. It counts lost productivity for the individual. It does not count a parent leaving work, which is one of the largest real costs families face.

A lifetime cost estimator on this site shows ranges built from that study with the sources attached. It is a planning aid, not a valuation.

If a legal case is filed, cost is estimated by a life care plan written for your child specifically. That is the only version of this number that is about your child rather than about a population.

What can you do this week?

1. Ask what the MRI showed and when it was done. Ask for a copy of the radiology report, not a summary of it.
2. Ask which Sarnat stage was recorded, and at what time. Ask whether cooling was considered, and what the reason was for the decision either way.
3. Request the complete records for you and your baby. Do it now, while the hospital's own copies are fresh and complete. The records request builder writes both letters for you, with your state's fee limit and deadline.
4. Write down what you remember about the labor, hour by hour. Memory fades faster than you expect. The delivery timeline builder prompts you for the details that turn out to matter.
5. Refer your child to early intervention. You can do this yourself today, before any diagnosis is confirmed. Use the early intervention finder.
6. Ask whether the placenta was sent to pathology, and request that report separately. It is often filed apart from the rest of the chart.
7. Start a binder. The NICU binder pack prints out with tabs and daily log sheets.

What should you ask each specialist?

Take these with you. Write the answers down in the moment, because you will not remember them later.

For the neonatologist

• Which Sarnat stage was my baby, and at what time was that recorded?
• Was therapeutic hypothermia considered? What was the decision, and why?
• What were the cord blood gas results, including pH and base deficit?
• What did the MRI show, and which areas of the brain are involved?
• Was an EEG done, and did it show seizures that we could not see?
• Was the placenta sent to pathology? Can I have that report?
• What are you watching for in the next 48 hours?

For the pediatric neurologist

• Based on the MRI, which functions are most likely to be affected?
• What would you expect to see by 6 months if things are going well? What would concern you?
• Does my child need seizure medicine at home, and for how long?
• How often should we come back, and what will you check each time?
• Which parts of the outlook are genuinely uncertain right now?

For the developmental pediatrician or the therapy team

• Which therapies do you recommend, how often, and what is the goal of each?
• What should we practice at home between sessions?
• How will we know whether therapy is working?
• When should we look at equipment, and who prescribes it?
• Who coordinates all of this, and how do I reach that person?

You can also build a printable list with the question generator.