Birth Asphyxia & Hypoxic-Ischemic Encephalopathy

Birth asphyxia, or oxygen deprivation around the time of birth, is a common cause of infant brain damage. Brain damage and other complications arising from birth asphyxia are called “birth injuries.”

If a baby does not have enough oxygen in their blood, or if blood flow to the brain is restricted, they may be born with a serious birth injury called hypoxic-ischemic encephalopathy (HIE). HIE can be treated with therapeutic hypothermia (cooling), but this therapy must begin within six hours of the time the birth asphyxia occurred (1). Therapeutic hypothermia may reduce or prevent permanent brain damage in some babies. For many babies, however, HIE causes long-term problems, such as the following:

Birth Asphyxia and Hypoxic-Ischemic Encephalopathy


Causes of birth asphyxiaBirth asphyxia

To get to an unborn baby, oxygen must travel through the mother’s lungs, heart, vasculature, uterus, and placenta, and then go through the umbilical cord. An issue at any point in this pathway can result in birth asphyxia, especially if the mother and baby do not receive proper medical care. The following are some common causes of fetal oxygen deprivation/birth asphyxia:

  • Placental abruption: This is a complication in which the placenta separates from the wall of the uterus before the baby is born. Abruption can cause severe maternal bleeding and loss of oxygen to the baby (3).
  • Uterine rupture: This occurs when there is a tear in the uterus/womb. A ruptured uterus can cause severe hemorrhaging in the mother and oxygen loss in the fetus (4).
  • Umbilical cord problems: Cord complications include cord prolapse, nuchal cord, short cord, and true knot. All of these conditions can cause severe oxygen deprivation in the baby (5).
  • Placental insufficiency: When vessels in the placenta are abnormal or compromised, the baby may experience long-term deprivation of oxygen and nourishment. In addition to birth asphyxia, they may have intrauterine growth restriction (IUGR) /fetal growth restriction (FGR) (6).
  • Preeclampsia: This occurs 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 (7).
  • Placenta previa: This occurs 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 (8).
  • Stroke: A fetal stroke occurs when blood vessels in the baby’s brain become blocked or restricted. This can be caused by birth asphyxia.   Hypoxic-ischemic encephalopathy (HIE) and stroke often occur together (9).
  • Premature rupture of the membranes (PROM): PROM occurs when the mother’s water breaks before she goes into labor. PROM can lead to umbilical cord prolapse and compression, and ultimately causes a lack of oxygen to the baby’s brain (10).
  • 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 (11).
  • Oligohydramnios: 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, which may lead to birth asphyxia (12).
  • Maternal hypotension: Spinal anesthesia can cause low blood pressure (hypotension) in the mother, and lead to a hypotensive crisis (13). In addition to endangering the mother’s life, this can cause birth asphyxia (14).
  • Failure to quickly deliver the baby when oxygen deprivation (fetal distress) is evident on the heart rate monitor (see our page on delayed emergency C-section for more information).
placenta; fetal oxygenation; pregnancy; umbilical cord

Normal placenta and umbilical cord function


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
  • 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 (15). A hypoxic-ischemic brain injury can progress over over minutes to hours, which is why it is important for the medical team to perform  brain imaging studies on a baby with encephalopathy and quickly intervene.  This often involves providing therapeutic hypothermia, which will be discussed in more detail later.


Signs of birth asphyxia

A baby with birth asphyxia may exhibit the following signs:

  • Cerebral edema
  • 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 (16)
  • Low Apgar scores (17)

Types of birth asphyxia

There are two main patterns of injury caused by birth asphyxia:

  • Acute near total asphyxia: This may also be referred to as basal ganglia-thalamus pattern of injury. It primarily involves the central grey nuclei and perirolandic cortex, and may also affect the hippocampus and brainstem. Acute near total asphyxia most commonly occurs after a major event such as a uterine rupture, placental abruption, or umbilical cord prolapse. This type of brain injury often results in fairly severe cases of cerebral palsy.
  • Partial, prolonged asphyxia: This may also be referred to as a watershed predominant injury pattern. It affects the vascular watershed zones. In more severely affected infants, the overlying cortex may be involved. Partial, prolonged asphyxia is most commonly caused by slower-acting issues such as hypotension, infection, and hypoglycemia. Infants with this type of injury are less likely to develop severe motor impairments, but it often manifests in other issues such as slow head growth, behavior problems, cognitive impairments, and language delays.

Please note that not every patient’s injuries will fit neatly into one of these categories; there are also many other patterns that asphyxia may take (18).


Therapeutic hypothermia for hypoxic-ischemic encephalopathy

Therapeutic hypothermia (brain cooling) is a treatment that can prevent or minimize permanent injury in babies with HIE, provided that it is given within six hours of birth (although some research shows that it may have value if initiated up to 24 hours after birth [19]). Therapeutic hypothermia has been shown to halt almost every injurious process that starts to occur when the brain experiences asphyxia. It may be able to prevent the development of cerebral palsy, or result in a less severe form of cerebral palsy (20).


Other treatments for hypoxic-ischemic encephalopathy

In addition to providing therapeutic hypothermia, the medical team must also carefully monitor the baby’s health and prevent harm from health complications that are often associated with HIE. These include seizures, poor perfusion, imbalances of electrolytes and blood sugar, brain bleeds, respiratory problems, and infections (21).

In the long-term, babies with HIE require frequent follow-ups in order to detect developmental issues/potential disabilities and provide early forms of intervention. These may include physical therapy, occupational therapy, speech therapy, medications, surgeries, and a variety of other options.    


How do you pronounce birth asphyxia?


Award-winning birth asphyxia 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 has been advocating for children with birth injuries stemming from asphyxia and medical malpractice for over three 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 firm has numerous multi-million dollar verdicts and settlements that attest to our success, and you pay us nothing 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.


Sources

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  4. Toppenberg, K. S., & Block, J. W. (2002). Uterine rupture: what family physicians need to know. American family physician, 66(5), 823-828.
  5. Umbilical Cord Complications: Overview, Cord Length, Single Umbilical Artery. (2018, June 01). Retrieved from https://emedicine.medscape.com/article/262470-overview
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  7. Backes, C. H., Markham, K., Moorehead, P., Cordero, L., Nankervis, C. A., & Giannone, P. J. (2011). Maternal preeclampsia and neonatal outcomes. Journal of pregnancy, 2011.
  8. Berhan, Yifru. “Predictors of perinatal mortality associated with placenta previa and placental abruption: an experience from a low income country.” Journal of pregnancy 2014 (2014).
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  16. Hypoxic-Ischemic Encephalopathy Clinical Presentation: History, Physical Examination. (2018, July 26). Retrieved from https://emedicine.medscape.com/article/973501-clinical#b2
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