Hypoxic-Ischemic Encephalopathy Lawyers
Importance of Fetal Circulation and Oxygenation of the Blood
Humans need to breathe. No matter what age you are, blood MUST circulate to deliver oxygen and nutrients to your cells, and remove waste and toxic buildup. Without oxygen, your cells will die. If enough tissues are affected, serious medical conditions or death occur.
Babies are especially vulnerable. During the vital perinatal period - a few weeks to a month before, during, and after birth - any interruption of oxygen to the growing brain is dangerous.
Blood circulation is what supplies the body’s cells with oxygen for proper function. When the brain is deprived of oxygen, severe brain damage or death can occur.
What Happens If a Baby’s Brain Doesn’t Get Oxygen?
The brain uses around 20% of the body’s total oxygen. In the womb, developing babies get oxygen, nutrients and get rid of waste through the umbilical cord that attaches the mother to the baby. Oxygen for breathing is delivered through the mother’s bloodstream. Sometimes, during pregnancy, labor or delivery, this oxygen supply can be diminished or cut off completely. When the supply of blood and oxygen is disrupted, the baby is at risk. That baby can only survive for a short period of time when the flow of oxygen is slowed or stopped.
When starved of oxygen for too long, cells start to die. If too many brain cells die during labor, life-long brain damage occurs. There are several medical terms used to describe this - cerebral asphyxia, hypoxic ischemic injury (HI), hypoxic-ischemic encephalopathy (HIE), perinatal hypoxia, or perinatal asphyxia are the usual descriptors.
What Is Hypoxic-Ischemic Encephalopathy?
Hypoxic-ischemic encephalopathy is a clinical diagnosis of widespread and irreversible damage of the baby’s brain (encephalopathy) due specifically to too little oxygen in the bloodstream (hypoxemia) and/or because the blood flow to the baby was reduced or stopped (ischemia).
There are two different injuries that can occur with HIE: the first involves the oxygen deprivation, which starves the cells of oxygen and nutrients causing injury. The second occurs as blood flow/oxygen is re-circulated into the damaged cells, which causes them to release toxins in what is called "reperfusion injury."
HIE is estimated to occur in approximately 1 - 3 per 1,000 live full-term births. Of these, 15% - 20% of affected newborns will die in the postnatal period, and an additional 25% will develop severe and permanent neuropsychological sequelae (conditions arising from the previous injury), including mental retardation, visual motor or visual perceptive dysfunction, increased hyperactivity and attention disorders, cerebral palsy, autism, epilepsy, etc. Other organs may or may not be damaged along with the baby’s brain; most commonly, the central nervous system, then the kidneys.
Severe cases of HIE are often apparent at the time of birth. There is a range of severity of injury so some injuries may not become apparent until after birth.
Fetal Circulation: How Do Babies "Breathe" During Pregnancy and Labor?
How Does Fetal Circulation Work?
During pregnancy, the baby or "fetus" is not breathing with lungs. Instead, the mother’s placenta (an organ that develops and implants in the womb) and umbilical cord create a channel where blood circulates to and from the baby. All oxygen and nutrition are sent to the baby, while waste products and carbon dioxide are sent back to the mother’s circulation to be eliminated.
"Breathing" or gas exchange (i.e., oxygen for carbon dioxide) happens in the placenta itself in intervillous space. There, oxygenated blood from the mother diffuses into blood vessels in the placenta. The umbilical vein takes this blood to the baby.
The circulating blood bypasses the lungs and enters fetal circulation through special openings called shunts. The purpose of shunts is to bypass developing body parts (specifically, the lungs and liver).
The enriched blood comes through the umbilical cord and enters through a shunt near the baby’s liver called the ductus venosus. Some blood goes into the liver, but most travels on through the inferior vena cava into the right atrium of the heart. It is then pumped out to the rest of the body in a "normal" circulatory pattern.
And when the blood with waste products and carbon dioxide comes back to the heart, instead of being "oxygenated" by the baby’s own lungs, there are two shunts in place: the foramen ovale, which bypasses the lungs, and the ductus arteriosus, which moves blood from the pulmonary vein to the aorta and on to the two umbilical arties, back into the placenta for Mom to deal with.
How Does the Baby Switch to "Normal" Circulation During Birth?
Up until the umbilical cord is clamped at birth, the baby is still "breathing" through the mother’s umbilical cord. After the cord is cut, babies have to breathe on their own, with oxygen sucked in through the nose or mouth and pulled into the lungs. With the first breaths of air, the baby’s lungs expand, and the alveoli in the lungs are cleared of fluid. The resulting increase in the baby’s blood pressure and reduction in the pulmonary pressure promotes the closure of the ductus arteriosus. That in turn increases pressure on the left atrium of the heart and decreases pressure in the right atrium, which stimulates the foramen ovale to close.
With these shunt closures, the baby’s circulation and blood flow through the heart just like a person. Sensors in the brain, carotid artery, and aorta detect the carbon dioxide and oxygen levels in the newborn’s blood and send the data up to the brain stem, which regulates breathing. Other sensors in the airways, lungs, and muscles also contribute to respiration.
During delivery, a number of factors can affect a baby’s ability to get oxygen.
How Can the Baby’s Circulation Be Disrupted During Birth?
During birth, HIE is possible through several different avenues: lack of oxygen, untreated jaundice, maternal infections, physical trauma, and even low glucose levels.
Lack of circulated oxygen can be the result of uterine contractions, compression or kinking of the umbilical cord, dangerous conditions such as uterine rupture or placental abruption, poor oxygen exchange or delivery from the mother to the baby through the placenta, as well as other conditions. When there is a condition causing lack of oxygen to the baby, the resulting "asphyxia" may be classified as "near total asphyxia" or "partial prolonged asphyxia" depending on the whether the oxygen deprivation was severe and happened quickly or acutely ("near total asphyxia") or the oxygen deprivation was less severe but happened over a longer period of time ("partial prolonged asphyxia").
When a baby doesn’t get enough oxygen and is asphyxiated, the baby can develop a condition called metabolic acidosis. Metabolic acidosis is a biochemical abnormality that develops when a baby suffers lack of oxygen either by hypoxia or ischemia or both for a sufficient length of time and magnitude to require anaerobic metabolism in the cells - metabolism without the normal amount of oxygen. Anaerobic metabolism produces lactic acid, which can accumulate and destroy brain cells, causing brain injury. Metabolic acidosis is associated with neurological impairment and multi-organ dysfunction in hypoxic-ischemic encephalopathy and cerebral palsy. Metabolic acidosis is detected by sampling the arterial blood from the umbilical cord and measuring the pH and base excess of the umbilical cord arterial blood.
Here are lists of some of the known causes of HIE:
Maternal Causes (conditions involving the mother which affect the flow of blood and oxygen to the baby):
- Hypotension (low blood pressure)
- Hypertension (high blood pressure)
- Infertility treatments
- Vascular or blood disorders
- Thyroid disorders
Placenta & Umbilical Cord Causes:
- Umbilical cord problems
- Uterus problems
- Placental problems
Fetal Causes (problems with the baby):
- Fetal intolerance to labor
- Blocked airways
- Severe circulatory insufficiency
- Severe respiratory distress syndrome (RDS)
Labor Room Causes:
- Delay in performing Cesarean section
- Physical trauma during labor and delivery including the use of forceps or a vacuum extractor
- Getting stuck in the birth canal
- Excessive pulling
- Breech extraction
- Dropped glucose levels
- Untreated jaundice
Many of these problems can be prevented if the healthcare provider is diligent in monitoring and treating the baby QUICKLY.
What Are the Symptoms of HIE?
Hypoxic-ischemic encephalopathy depends on three factors: the severity, timing, and duration of the "insult" (cause of the injury). Here are some signs that a baby is suffering from a neurological injury to the brain:
The First 24 Hours
- Baby is not breathing or baby’s heart is not beating at birth
- Not easily awakened or stimulated
- Apnea (temporary stops in breathing)
- Bradycardia (abnormally slow heartbeat)
- Eye responses may be intact, with or without spontaneous eye movements
- Hypotonia or low muscle tone, "floppy baby syndrome"
- Jitteriness or seizures (some of them only detectable by EEG)
- Skin color may be "cyanotic" (blue) or very pale
- Morro, grasp, suck, and swallow reflexes may be absent or "depressed" (reduced)
- Apgar score of less than three lasting longer than five minutes
12 - 24 Hours
- Apparent increase or decrease in level of alertness
- Jitteriness and limb weakness
- Exaggerated Morro and deep tendon reflexes
- Shrill and monotonous cry
24 - 72 Hours
- Level of consciousness deteriorates
- Can experience respiratory arrest
- Signs of brainstem dysfunction: absent doll’s eyes, fixed or dilated pupils
Mild hypoxic-ischemic encephalopathy may resolve. Moderate cases may or may not recover. Severe cases include:
- Stupor or coma; the infant may not respond to any physical stimulus except the most noxious;
- Breathing may be irregular, and the infant often requires breathing support;
- Generalized hypotonia and depressed deep tendon reflexes are common;
- Neonatal reflexes (sucking, swallowing, grasping, Morro) are absent;
- Disturbances of eye motion;
- Pupils may be dilated, fixed, or poorly reactive to light;
- Irregularities of heart rate and blood pressure are common during period of reperfusion injury, as is death from cardiorespiratory failure.
How Is HIE Diagnosed?
Any signs of brain injury or abnormal neurologic function should be identified after birth. Signs may include:
- Metabolic or mixed academia in the umbilical artery blood sample;
- A low or abnormal Apgar score
- Newborn neurologic sequelae (like seizures, coma, hypotonia);
- Multiple organ involvement.
There are several tools used to diagnose. Sarnat Staging, for example, is based on the baby’s appearance:
Laboratory tests include those for arterial blood gas, coagulation system, cardiac and liver enzymes, renal (kidney) function, and electrolyte levels.
Neuroimaging through cranial ultrasonography (US), echocadiography, and magnetic resonance imaging (MRI) is increasingly vital for an early diagnosis. Of those three, MRI is probably considered the most valuable.
Electroencephalograms (EEGs) - since seizures are common in HIE, this is a valuable tool.
Hearing and eye exams may also be performed.
What Can Be Done for HIE?
Any type of fetal distress before, during, or after birth should be handled swiftly by medical providers. When a baby isn’t getting enough oxygen, every minute matters. Doctors, nurses, and midwives should know the signs that the baby isn’t getting enough oxygen and should be prepared to act quickly to protect the baby from injury and to prevent and mitigate brain injury and hypoxic-ischemic encephalopathy.
In cases of umbilical cord compression, prolapse, or nuchal cord (when the cord is wrapped around the baby’s neck), the doctor may need to do a Cesarean section delivery to get the baby out quickly, getting him or her breathing as soon as possible. When the baby’s oxygen supply is diminished or cut off, it only takes minutes before long-term damage can occur.
Mothers are usually at the mercy of their doctors, nurses, and hospitals. But that doesn’t mean they’re helpless. Here are a few things that may help:
- Be aware of the risks associated with birth and delivery.
- Be observant during the birth process.
- Ask questions. Ask to talk to the nurses and doctors about concerns.
- Insist on testing if anything seems off.
- If HIE is diagnosed, find out exactly what caused it.
Medical support provided to stabilize and treat HIE includes ventilation, perfusion blood pressure management (to prevent a "reperfusion injury" after the initial oxygen deprivation), fluid management, avoiding hypoglycemia and hyperglycemia, avoiding overheating, treating seizures, and therapeutic hypothermia (~33°C for 72 hours).
Early intervention is vital.
Do You Have Questions About a Birth Injury Diagnosis?
If your child has sustained a birth injury due to negligence, you may be entitled to compensation from the responsible party. However, you are understandably feeling hesitant about pursuing litigation. Most hospitals and medical insurance companies are powerful entities with the resources to employ upper-tier legal squads. At Birth Injury Safety, we help babies and their families. We investigate what happened and if we believe the injury was avoidable and should have been prevented, we stand ready to go up against even the largest of hospital corporations or insurance companies. Years of devoted practice have instilled us with confidence and experience and the skills to match. Please call us at (214) 974-4121 today and let Texas birth injury attorney Laura Brown protect your rights and the rights of your child.
Glossary of Medical Terms Used
- Hypoxemia: Low oxygen in the blood.
- Ischemia: Diminished/blocked blood flow to a part of the body.
- Hypoxia: Low oxygen in the tissues, representing a dangerous loss of oxygen to the brain or other body part.
- Anoxia: Complete lack of oxygen reaching the tissues; severe hypoxia.
- Asphyxia: Lack of total gas exchange (oxygen and carbon dioxide) causing suffocation.
- Perinatal asphyxia: Condition during labor in which impaired gas exchange leads to fetal hypoxemia and hypercarbia.
- Hypercarbia or hypercapnia: Elevated carbon dioxide levels in the blood.
- Perinatal/Neonatal depression: Condition of infant within one hour of birth - includes depressed mental status, muscle hypotonia, and possible disturbances in spontaneous respiration and cardiovascular function.
- Hypotonia: "Floppy baby syndrome" is a state of low muscle tone with very little flex or resistance in the muscles.
- Hypothermia: Having a body temperature greatly below normal.
- Encephalopathy: A disease, disorder, or syndrome of overall effects on the function or structure of the brain.
- Neonatal encephalopathy: Clinical term that describes an irreversible injury-induced abnormal neurobehavioral state (decreased level of consciousness, signs of brain stem and/or motor dysfunction).
- Hypoxic Ischemic (HI) brain injury: Injury due to hypoxia and/or ischemia (evidenced by biochemical, electrophysiological, neuroimaging, or pathologic (postmortem) abnormalities).
- Hypoxic-Ischemic Encephalopathy (HIE): Encephalopathy with proof of damage specifically from a hypoxic and/or ischemic cause.
- Reperfusion injury: When blood flow/oxygen is re-circulated into damaged cells, which causes them to release toxins that harm the tissues.
- Sequela: A medical condition or disorder that comes as a result of a previous injury or illness. From the Latin word meaning "that which follows, consequence."
Oxygen Deprivation and Your Newborn
Hypoxia means “oxygen deficiency.”
Hypoxia is a serious medical condition where the body is deprived of oxygen.
In the context of pregnancy, labor, and delivery; hypoxia, hypoxemia, ischemia, and asphyxia are all medical terms that refer to situations in which the baby did not get enough oxygen to function properly. This oxygen deprivation can result in severe damage to the brain called hypoxic-ischemic encephalopathy or HIE. It only takes a short time without adequate oxygen for brain cells to start to die, resulting in permanent injury.
During labor and delivery, it is critically important for hospitals, doctors, and nurses to carefully monitor whether the baby is receiving enough oxygen and is tolerating labor. When there are signs that the baby is not receiving enough oxygen, it may be necessary to deliver the baby quickly, either vaginally or by Cesarean section, to prevent injury to the baby.
Early Diagnosis and Treatment: Electronic Fetal Heart Monitoring
An unborn baby is often referred to as a "fetus," so the term "fetal heart rate" refers to the heart rate of the unborn baby.
Hospitals, doctors, and nurses monitor the fetal heart rate during labor and delivery with an electronic fetal heart monitor or EFM. The electronic fetal heart monitor attaches to the mother’s abdomen and traces the baby’s heart rate. The tracing is displaced either electronically on a monitor or on a printed graph. If a baby becomes hypoxic, or progresses to acidosis, the baby’s heart rate is affected. There are abnormal fetal heart rate patterns which sign that the baby isn’t getting enough oxygen and may need help.
Causes of Hypoxia
Hypoxia or inadequate oxygen to the baby can result from a number of different known complications during pregnancy, labor, and delivery.
Umbilical cord problems:
The mother provides oxygen and nutrients to the baby in the blood that flows through the umbilical cord. If the umbilical cord is compressed or kinked, the flow of blood between the mother and the baby is either reduced or stopped entirely.
The uterus is the organ of the mother’s body that houses the baby during pregnancy. The uterus is a muscular organ that can contract and relax. There are different types of complications involving the uterus that can affect flow of blood and oxygen to the baby.
- Uterine rupture
- Uterine hyperstimulation or tachysystole
- Uteroplacental insufficiency
The placenta is an organ of the mother’s body that is created during pregnancy. It exists inside the mother’s uterus. The placenta attaches to the inside of the uterine wall and attaches to the baby by the umbilical cord. The exchange of oxygen, carbon dioxide, and nutrients between the mother and the baby happens in the placenta. There can be complications with the placenta that deprive the baby of adequate oxygen.
These are some examples of common complications that occur during labor and delivery which cause hypoxia. Medical professionals must be well-trained to recognize these complications and to act quickly to protect the baby. When hospitals employees, nurses, and doctors fail to recognize the abnormal fetal heart rate patterns and take action, this is a form of medical negligence which can result in a birth injury.
According to a recent study published in Acta Obstetricia et Gynecologica Scandinavica, human error is the most common cause of hypoxia and infant asphyxiation. Examples of preventable medical errors include failure to train employees on fetal heart monitoring and interventions for hypoxia, inadequate fetal heart monitoring, failure to communicate timely and appropriately between medical professionals, etc.
Consequences of Hypoxia
Hypoxia is extremely dangerous and can lead to life-threatening conditions.
Hypoxia during birth can progress to asphyxia (absence of oxygen), acidosis, and brain injury including hypoxic-ischemic encephalopathy (HIE).
Infants with hypoxic-ischemic encephalopathy typically have depressed neurologic function after birth, requiring medical support for breathing and maintaining blood pressure and cardiac activity. Many have seizures. Those who survive may experience mental retardation, epilepsy, or cerebral palsy. Some symptoms occur right away while others may not exhibit until later in life, making HIE difficult to diagnose.
Legal Rights of an Injured Baby
If your child was born with a serious birth injury, it may be in your child’s best interest to research your legal options. If the negligence of a medical professional caused your baby's injury, the law may permit recovery of damages for medical bills, hospitalization, surgeries, rehabilitation, cost of future treatment and care, and pain and suffering. Providing your child with the treatment and quality of life he or she needs can get extremely costly. Not all medical or rehabilitation costs may be covered by medical insurance. Children who have suffered severe, irreversible brain damage due to hypoxia may require round-the-clock treatment and care.
You may have to act quickly to hold the at-fault party accountable because there is a statute of limitations on all birth injury cases. If you wait too long to file a claim, you may not be able to recover the financial support your child needs. Birth Injury Safety will fight to protect your child's rights and ensure that you are fairly and fully compensated for your losses. Please contact us at (214) 974-4121 for a free consultation and comprehensive case evaluation.
Did Your Baby Suffer an Asphyxial Injury?
Birth (or perinatal) asphyxia is a medical term used to describe the time period at which a baby suffered an asphyxial injury - an injury due to a lack of oxygen. "Birth asphyxia" refers to a lack of oxygen specifically at the time of labor and delivery.
Injuries to the baby’s brain can be caused by lack of oxygen during labor and delivery either by decreased blood flow to the brain (ischemia) or by diminished oxygen content in the blood flowing to the brain (hypoxia). Diagnoses commonly given to babies who have experienced birth or perinatal asphyxia are "neonatal encephalopathy" and "hypoxic-ischemic encephalopathy" or "HIE."
Causes of Birth Asphyxia
Asphyxia is caused by a lack of oxygen. Without enough oxygen, cells cannot function properly and acidic waste products can build up in the cells, causing temporary or permanent damage. Birth asphyxia occurs when the infant’s brain or other organs are oxygen-deprived before, during, or shortly after birth.
Common causes of birth asphyxia include:
- Prolonged or difficult delivery;
- Insufficient oxygen in the mother’s blood before or during birth;
- Umbilical cord problems during delivery;
- Serious infection in the mother or infant;
- Placental abruption or separation of the placenta from the uterus too soon;
- Uterine rupture
- High or low blood pressure in the mother;
- Infant’s blood cells cannot carry enough oxygen due to anemia;
- Infant’s airways are blocked; or
- Meconium aspiration at the time of delivery.
Birth Asphyxia Symptoms
It is important for physicians and other attending medical professionals to recognize the symptoms of birth asphyxia and act immediately to provide emergency medical treatment. Symptoms of asphyxia at the time of birth may include:
- Not breathing, or breathing is weak;
- Pale or bluish skin color;
- Low heart rate;
- Poor muscle tone or weak reflexes;
- Acidosis (excess acid in the infant’s blood); or
- Amniotic fluid stained with meconium.
Monitoring for Birth Asphyxia
At birth, the doctor should carefully evaluate the baby’s condition and assign an Apgar score. The Apgar score is a subjective rating of the baby’s heart rate, skin color, reflexes, muscle tone, and breathing effort. The doctor or nurse assigns a number from 0 to 2 for each item. The highest overall score is 10. A low Apgar score can indicate birth asphyxia.
An infant who has been deprived of blood flow and oxygen may have poor circulation, lethargy, abnormal breathing, blood-clotting abnormalities, and lack of urine output. Physicians must act quickly to provide the proper treatment to help prevent further injury to the child.
Birth Asphyxia Treatment
Treatment for birth asphyxia depends on the severity. Babies born with mild asphyxia are provided with breathing support until they are breathing well on their own, and then monitored closely.
Infants with more serious birth asphyxia may need a breathing machine, respiratory therapy, and fluid and medications to prevent seizures and control blood pressure. Feedings may need to be delayed until the baby’s bowels recover.
Advanced treatment options for birth asphyxia include:
- High frequency ventilation: This is a gentler form of mechanical ventilation that sends small puffs of air rapidly into the baby’s lungs. Unlike high-pressure conventional breathing machines, this type of breathing assistance is intended to protect a newborn’s fragile lungs from damage.
- Inhaled nitric oxide: This is used to treat respiratory failure and pulmonary hypertension (high blood pressure in the lungs). The nitric oxide goes directly into the windpipe through a breathing tube to help dilate blood vessels in the lungs so they can carry blood and oxygen to the body.
- Hypothermia: Cooling the infant’s internal body temperature to approximately 91 degrees Fahrenheit for up to 72 hours can help prevent brain damage during the second stage of asphyxia. This is the stage known as "reperfusion," when normal blood flow and oxygen are restored to the brain. The treatment works best when started within six hours after birth. To qualify for hypothermia treatment, the infant must not be more than four weeks early.
- Extracorporeal membrane oxygenation (ECMO): A heart-lung pump is used to provide temporary life support when the child’s heart and lungs are not functioning properly. The baby’s blood is drawn into a machine that adds oxygen, removes carbon dioxide, and returns the oxygen-rich blood to the body. An infant on ECMO is sedated and closely monitored.
Birth Injury Damages
Although birth injuries happen in the earliest stages of life, they can result in damages that last for a lifetime. The expenses associated with long-term medical treatment for a birth injury are usually very extensive and can devastate the family’s finances. If your child is a birth injury victim, you should get in touch with birth injury attorney Laura Brown as soon as possible. We will use the full scope of our legal skills and knowledge to help you attain a fair settlement from the liable party that will sufficiently cover all of your child’s needs. To learn more, contact our office at (214) 974-4121.
Ischemia – Lack of Blood Flow
Ischemia refers to a lack of blood flow or reduced blood flow to an organ or part of a body.
Since unborn babies do not "breathe" through their lungs, the oxygen that they need to survive is in their mothers’ blood. A mother provides oxygen and nutrients to her baby in the blood that flows through the placenta and the umbilical cord. When this blood flow is reduced or stopped, the baby’s brain and other organs are deprived of vital oxygen and nutrients.
Ischemia can result in hypoxia (lack of oxygen) to the brain, which may then lead to acidosis, birth asphyxia, brain cell death, and permanent brain injury.
Causes of Ischemia:
Internal problems that often cause ischemia include:
- Uterine rupture
- Placental abruption
- Umbilical cord compression/umbilical cord prolapse
- Placenta previa
Immediate Action to Protect the Baby
Lack of adequate blood flow to a baby can be an emergency. Hospitals, doctors, and nurses should carefully monitor the baby’s heart rate for signs that the baby isn’t getting enough oxygen, so that the medical team can act quickly to protect the baby if needed.
Contact Birth Injury Safety If You Need Help
Birth injury cases are a type of medical malpractice. The medical issues involved in birth injury lawsuits can be complex. Attorney Laura Brown has spent years researching and representing babies who have suffered birth asphyxia, hypoxic-ischemic encephalopathy, and cerebral palsy. Please call (214) 974-4121 or email Laura at Brown@TrialFirm.com if you would like to talk to her about what happened in your delivery and find out if your baby’s injury was preventable.
- Asphyxia Blogs
- Do You Have A Legal Claim if Your Child Was Deprived of Oxygen at Birth?
- Survival Rate for Newborns with Birth Asphyxia Improved by Head Cooling Treatment
- American Heart Association: Fetal Circulation
- Stanford Children's Healh: Blood Circulation in the Fetus and Newborn
- Universities of Fribourg, Lausanne and Bern (Switzerland): Embryo-fetal Circulation System - Changes at Birth
- International Brain Injury Association: Hypoxic-ischemic Brain Injury
- Radiological Society of North America: Hypoxic-Ischemic Brain Injury: Imaging Findings from Birth to Adulthood
- Medscape: Hypoxic-Ischemic Encephalopathy
- WebMD: Hypoxia and Hypoxemia
- National Center for Biotechnology Information: Five Cases of Brain Injury Following Amniocentesis in Mid-Term Pregnancy
- CDC: Achievements in Public Health, 1900-1999: Healthier Mothers and Babies
- National Heart, Lung and Blood Institute: What Controls Your Breathing?
- Princeton Brain & Spine: Brain Anatomy
- National Center for Biotechnology Information: Perinatal Hypoxic-Ischemic Encephalopathy
- National Center for Biotechnology Information: Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. - Hypoxic Encephalopathy
- Youtube: HIE Presentation by Dr. Sonali Paradhi Mhatre