Birth Asphyxia & Hypoxic-Ischemic Encephalopathy
A lack of oxygen to a baby’s brain, or birth asphyxia, is the most common cause of birth injuries in newborns. Birth asphyxia and decreased blood flow to the baby’s brain can result in a serious condition called hypoxic-ischemic encephalopathy (HIE). HIE can be treated with hypothermia (brain cooling) therapy, but the cooling must begin within 6 hours of the time the birth asphyxia occurred. Treatment may help some babies avoid permanent brain damage. For many babies, however, HIE and other brain injuries cause long-term problems such as the following:
- Periventricular leukomalacia (PVL). HIE usually involves damage to the basal ganglia and watershed regions of the brain, but sometimes also includes PVL.
- Neonatal encephalopathy
- Seizure disorders
- Cerebral palsy (CP)
- Intellectual disabilities
- Developmental delays
- Motor disorders
Causes of Birth Asphyxia
An unborn baby receives oxygen-rich blood through the following pathway: maternal circulation –> uteroplacental circulation –> umbilical vein –> fetal circulation. There are numerous causes of birth asphyxia, but the most common causes include problems with the uterus, placenta, and umbilical cord. A very low blood pressure in the mother is another common cause of birth asphyxia, since it usually results in decreased uteroplacental circulation.
The following is a list of conditions that can cause birth asphyxia if not properly managed. These conditions usually occur during or near the time of delivery:
- Placental abruption. This is where an organ crucial in delivering oxygen-rich blood to the baby – the placenta – separates from the wall of the uterus. Abruption can cause severe bleeding and loss of oxygen to the baby.
- Uterine rupture. This occurs when there is a tear through all the layers of the womb. A ruptured uterus can cause severe hemorrhaging in the mother, and the baby can float out of the womb and into the mother’s abdomen. The rupture may be at a spot that affects the blood circulation between the uterus and placenta, or the hemorrhaging can simply cause the mother to lose so much blood that there is a decreased flow of blood to the baby.
- Umbilical cord problems. These include cord prolapse, nuchal cord, short cord, and true knot. All of these conditions can cause severe oxygen deprivation in the baby.
- Uteroplacental insufficiency/placental insufficiency. When vessels in the uteroplacental circulation are abnormal or compromised, the baby may experience long-term deprivation of nourishment. Uteroplacental insufficiency can cause intrauterine growth restriction (IUGR) /fetal growth restriction (FGR).
- Preeclampsia. This is when the mother has high blood pressure diagnosed during pregnancy, which can cause a decreased flow of blood to the baby and other serious problems, including eclampsia.
- Placenta previa. This is when the placenta grows close to the opening of the uterus, partially or completely blocking the mother’s cervix, which is the opening to the birth canal.
- Stroke. A fetal stroke occurs when blood vessels in the baby’s brain become blocked or restricted. Forceps and vacuum extractors can cause the baby to have a stroke, which can result in severe oxygen deprivation. Hypoxic-ischemic encephalopathy (HIE) and stroke often occur together.
- Premature rupture of the membranes (PROM). PROM occurs when the water breaks before the mother goes into labor. PROM can lead to umbilical cord compression as well as premature birth, and ultimately causes a lack of oxygen to the baby’s brain.
- Prolonged and arrested labor. Contractions during labor are difficult for the baby, and when labor is prolonged, there can be a dangerous lack of oxygen to the fetal brain. Prolonged/arrested labor is often caused by misuse of Pitocin and Cytotec.
- Oligohydramnios (low amniotic fluid). This is a condition in which the mother has low amniotic fluid. Oligohydramnios puts the baby at significant risk of having a prolapsed or compressed umbilical cord. Oligohydramnios can also lead to meconium aspiration, which can cause respiratory distress and oxygenation problems.
- Anesthesia mistakes. Improper use or dosage of anesthesia can cause blood pressure problems – especially low blood pressure – in the mother, and lead to a hypotensive crisis. When a mother’s blood pressure drops too low, there will be a decreased supply of oxygen-rich blood going to the baby.
- Intracranial hemorrhages (brain bleeds), which can be caused by a traumatic delivery. Brain bleeds may be caused by misuse of birth-assisting tools like forceps and vacuum extractors, or misuse of labor induction drugs (Pitocin and Cytotec).They can also be caused by mismanagement of cephalopelvic disproportion (CPD), prolonged or arrested labor, abnormal presentations (face or breech presentation), and shoulder dystocia.
- Failure to quickly deliver the baby when oxygen deprivation (fetal distress) is evident on the heart rate monitor (delayed emergency C-section).
How Does Birth Asphyxia Cause Brain Injuries?
The degree of brain injury a baby experiences when birth asphyxia occurs depends on the severity of the birth asphyxia, how long the asphyxia lasts, the baby’s age and oxygen reserves, and medical management of the baby during and after birth. When a baby is experiencing birth asphyxia, the fetal heart rate monitor will exhibit nonreassuring heart tracings. When these tracings occur, the medical team should perform interventions – such as giving the mother IV fluids, changing the mother’s position, and giving oxygen – designed to increase blood flow and oxygenation in the baby. While these interventions are taking place, the team should also prepare for a prompt C-section delivery. A C-section delivery is usually the fastest and safest way to deliver a baby in distress. The sooner the baby is delivered, the sooner the medical team can directly help them.
When birth asphyxia occurs, the baby becomes hypoxic (has insufficient oxygen) and usually hypercarbic (has high carbon dioxide in the blood). Hypoxia causes anaerobic metabolism and lactic acid production. When a lot of acid builds up in the baby’s blood, it is called acidosis. Acidosis and hypoxia can decrease heart function, which can cause the baby to have very low blood pressure (hypotension) and insufficient blood flow in the brain (ischemia). Ischemia then further impairs oxygen delivery to the baby. Hypoxia and ischemia also result in a cascade of events that disrupt metabolic pathways. Prolonged birth asphyxia causes the baby to have a hypoxic-ischemic state, which causes the brain to be deprived of glucose and all other nutrients as well as oxygen. In addition, the process of waste-removal is disrupted, which causes more metabolic issues and other health problems. Typically, the longer a hypoxic-ischemic state continues, the more injury there will be to the brain.
If a hypoxic-ischemic event is severe enough to damage the brain, the baby will usually develop cerebral edema within 12 – 24 hours. A baby with HIE may exhibit the following signs:
- Seizures, especially within the first 24 – 48 hours of life
- Hypotonia (baby is floppy/limp)
- Poor feeding
- Depressed level of consciousness
- Multiple organ problems
- Breathing problems
- An abnormal response to light
At birth, babies with HIE may also have had the following:
- A need for resuscitation
- A low Apgar score for longer than 5 minutes
- An acidic umbilical cord blood gas (profound metabolic or mixed acidosis)
The type of brain damage a baby experiences depends on the type and extent of birth asphyxia:
- Total/near total asphyxia: Usually the deep gray matter is injured. This may include structures like the basal ganglia, thalamus, and brain stem.
- Partial, prolonged asphyxia: this mainly leads to cortical injury in the watershed and parasagittal regions, with relative sparing of damage to the deep gray matter.
Babies can also experience more than one type of asphyxia, which causes a mixed brain injury pattern.
Hypoxic-Ischemic Brain Injury Is an Ongoing Process
Hypoxic-ischemic encephalopathy (HIE) is an evolving process. In addition to the first set of injurious events that start to occur when there is a hypoxic-ischemic/asphyxic insult, there is also a delayed cascade of molecular events triggered by the initial insult. For example, MRI studies show that the size of abnormal tissue (lesion size) increases over the first few days after injury. Within the first few hours after a baby experiences near total asphyxia, findings on MRI are usually subtle and are often only seen on a specific type of MRI called diffusion weighted imaging. This type of imaging typically shows initial small lesions in the putamen and thalami that usually progress over the next 3 – 4 days to involve more extensive regions of the baby’s brain.
Research shows that during this period of days after the initial asphyxic insult, many neurons and other cells are programmed to die or survive. Research has also helped scientists understand the progression of energy failure in the cell, as well as the severe cell swelling and accumulation of intracellular calcium that cause cell death. A hypoxic-ischemic brain injury can progress over days and weeks, which is why it is important for the a medical team to perform regular brain imaging studies on a baby with encephalopathy.
Hypothermia Treatment for Hypoxic-Ischemic Encephalopathy
Hypothermia (brain cooling) treatment for HIE has been shown to halt almost every injurious process that starts to occur when the brain experiences a hypoxic-ischemic/asphyxic insult. Scientists think that one of key reasons this treatment protects the brain is that it stops the signaling events inside the cells that initiate a cell death cascade. Hypothermia treatment can minimize the extent of permanent brain injury in a baby who has HIE. This treatment can help prevent a baby with HIE from developing cerebral palsy, or the baby may have a less severe form of CP.
Hypothermia treatment must, however, be given within 6 hours of the time the baby experienced the birth asphyxia, which often means that babies must receive the treatment within 6 hours of birth. Most hospitals have methods in place to quickly assess a baby’s eligibility for hypothermia treatment.
Other Treatments for Hypoxic-Ischemic Encephalopathy
When a baby has HIE, the medical team must make sure that there is no further disruption in oxygen and blood flow to the brain. In addition, they must ensure that the baby has good blood pressure, perfusion, oxygenation, ventilation, and acid content.
Seizures in the neonatal period are caused by abnormal brain activity, which can be from HIE. Seizures can cause brain injury and worsen existing brain damage, so they must be promptly diagnosed and treated. Many neonatal intensive care units throughout the U.S. have the ability to perform continuous electroencephalography (EEG), which is the recording of electrical activity in the brain. When a baby is suspected of having hypoxic-ischemic encephalopathy, they should have continuous EEG monitoring, if possible, or frequent EEG testing. Often, EEG results are the only indication a baby is having seizures.
Other signs of seizure activity include the following:
- Apnea (periods of breathing cessation)
- Repetitive facial movements, such as sucking, chewing, or eye movements
- Unusual bicycling or pedaling movements
- Clonic seizure activity, which consists of rhythmic jerking movements that may involve the muscles of the face, tongue, arms, legs, or other body regions
- Myoclonic seizure activity, which consists of quick, single jerks involving one arm or leg, or the entire body
- Tonic seizure activity, which involves stiffening or tightening of muscle groups; the head or eyes may turn to one side, or the baby may bend or stretch one or more arms or legs
If there is a metabolic or other underlying medical problem that may be causing the baby to have seizures, the problem should be promptly treated. Phenobarbital is the medication physicians usually give first to babies experiencing seizures.
How Do You Pronounce Birth Asphyxia?
Award-Winning Hypoxic-Ischemic Encephalopathy Attorneys
If you are seeking the help of a lawyer, it is very important to choose a lawyer and firm that focus solely on birth injury cases. Reiter & Walsh ABC Law Centers is a national birth injury law firm that has been helping children with birth injuries for almost 3 decades.
We have helped children throughout the country obtain compensation for lifelong treatment, therapy and a secure future, and we give personal attention to each child and family we represent. Our nationally-recognized birth injury firm has numerous multi-million dollar verdicts and settlements that attest to our success, and no fees are ever paid to our firm until we win your case. Contact us today for a free legal consultation:
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The information presented above is intended only to be a general educational resource. It is not intended to be (and should not be interpreted as) medical advice.
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