Neonatal Asphyxia
Neonatal asphyxia is a serious medical condition where a baby does not receive enough oxygen before, during, or right after birth. This lack of oxygen can cause damage to the brain and other vital organs, leading to long-term health problems or even death. Understanding this condition is essential for parents and families facing its consequences.
Table of contents
- What is neonatal asphyxia?
- Other names for this condition
- What causes neonatal asphyxia?
- Signs and symptoms
- How doctors diagnose neonatal asphyxia
- Stages of injury
- Treatment and management
- Can babies recover?
- Possible complications
- How common is this condition?
- Related health conditions
What is neonatal asphyxia?
Neonatal asphyxia occurs when a baby’s brain and other organs do not get enough oxygen and blood flow immediately before, during, or right after birth[1]. When oxygen supply is cut off or severely reduced, the baby’s body cannot function properly. This condition is also known as perinatal asphyxia or birth asphyxia[2].
The condition develops when the exchange of oxygen through the placenta before birth or through the lungs after birth is compromised or stops completely[1]. When this happens, there is a partial lack of oxygen (called hypoxia) or a complete lack of oxygen (called anoxia) to vital organs. This leads to progressive hypoxemia (low oxygen in the blood) and hypercapnia (too much carbon dioxide in the blood)[1].
If the oxygen shortage is severe enough, the body’s tissues and vital organs develop an oxygen debt. The body then switches to a different way of producing energy called anaerobic glycolysis, which creates lactic acidosis (a buildup of acid in the blood)[1].
birth asphyxia, perinatal asphyxia, acute neonatal encephalopathy
Other names for this condition
Medical professionals may use different terms when referring to this condition. Besides neonatal asphyxia, you might hear it called birth asphyxia, perinatal asphyxia, or acute neonatal encephalopathy[2].
What causes neonatal asphyxia?
Neonatal asphyxia can result from any condition that affects the flow of blood or oxygen to the baby[1]. The causes can be grouped into problems with the mother’s circulation or oxygen supply, issues with the placenta, or problems with the umbilical cord or the baby itself.
Common causes include problems with the placenta separating from the womb too soon, issues with the womb during labor, or problems with the umbilical cord during delivery[2]. Very long or difficult deliveries can also lead to oxygen deprivation, as can situations where the baby gets stuck during delivery[2].
Other causes include large amounts of blood loss during labor or delivery, high or low blood pressure in the mother, infections in the mother that interfere with oxygen flow, and problems with the baby’s airways being blocked or underdeveloped[8]. Sometimes meconium (the baby’s first feces) in the amniotic fluid can also cause breathing problems[10].
Problems with the mother’s heart and respiratory system can result in a lack of oxygen to the baby, as can uterine rupture or issues like placenta abruption (when the placenta separates from the uterus too early)[8]. Umbilical cord problems such as cord knotting, cord compression, or cord prolapse are also important causes[8].
Signs and symptoms
At the time of birth, babies with asphyxia may show several warning signs. These symptoms can range from mild to severe depending on how long the baby was without adequate oxygen[2].
Common symptoms include not breathing or very weak breathing, skin color that appears bluish, gray, or lighter than normal, and a low heart rate[2]. Babies may also show poor muscle tone (appearing floppy or limp), weak reflexes, and signs of too much acid in the blood (acidosis)[2].
In more severe cases, seizures may occur[2]. Some babies need help to breathe and maintain a heartbeat in the delivery room, a process called resuscitation[2].
After the initial period, babies may have trouble settling and being wakeful at first, but later they may become lethargic and show low muscle tone called hypotonia[8]. They may also have decreased muscle reflexes (hyporeflexia)[8].
Other signs include abnormal eye movements or pupil movements, weak or absent sucking ability, periods where breathing stops (apnea) or very rapid breathing (hyperpnea), and clinical seizures[1].
How doctors diagnose neonatal asphyxia
At birth, doctors and nurses carefully check the baby and rate their condition using a scoring system called the Apgar score[2]. This score rates skin color, heart rate, muscle tone, reflexes, and breathing effort on a scale from 0 to 10[7].
The Apgar score is recorded at 1 minute and at 5 minutes after birth. At 5 minutes, a score of 7 to 10 is considered normal, 4 to 6 is intermediate, and 0 to 3 is low[7]. A very low Apgar score (0 to 5) lasting longer than 10 minutes may be a sign of neonatal asphyxia[2].
Doctors will look for signs of a high level of acid in the blood, which can indicate the baby had low oxygen and blood flow. To check this, the care team will take a sample of the baby’s blood or cord blood at the time of birth or soon after[2].
According to the World Health Organization, neonatal asphyxia is characterized by several features: profound metabolic acidosis with a pH less than 7.20 in umbilical cord blood, persistence of an Apgar score of 3 at the 5th minute, clinical signs of brain problems in the immediate newborn period, or evidence of multiple organ system problems in the immediate newborn period[5].
Doctors will also examine the baby for signs of abnormal brain function[2]. Additional tests may include magnetic resonance imaging (MRI) to look for characteristic findings that indicate brain damage[1].
Stages of injury
When a baby experiences neonatal asphyxia, the injury can happen in two stages[2].
The first stage happens within minutes if blood flow is low and cells do not get enough oxygen. During this initial phase, immediate damage begins to occur to brain cells and other organs[2].
The second stage is called reperfusion injury and can last for days or even weeks[2]. After the brain starts getting normal levels of blood and oxygen again, the damaged cells release chemicals that cause additional harm. This is why quick treatment is so important, as it can help limit damage during both stages.
Treatment and management
Treatment begins immediately in the delivery room following standard resuscitation guidelines. Medical staff pay close attention to ensuring appropriate oxygen delivery, maintaining proper blood flow (perfusion), avoiding low blood sugar (hypoglycemia) and high blood sugar (hyperglycemia), and preventing the baby from getting too warm (hyperthermia)[17].
For babies born after 35 weeks of pregnancy who have moderate or severe asphyxia, whole-body cooling (also called therapeutic hypothermia) is currently the only treatment proven to improve outcomes[2]. This treatment must be started within 6 hours after birth[17].
During cooling therapy, the baby’s core body temperature is lowered to 33.5°C and maintained at that level for 72 hours[15]. After the cooling therapy is completed, the baby is gradually rewarmed to a normal temperature of 36.5–37°C[15]. This cooling helps slow down or stop the damaging effects of asphyxia on the brain[2].
Supportive care is also critical and includes ensuring adequate oxygen levels, proper breathing support, careful fluid management, and treatment of seizures if they occur[1]. Babies may need medications to help their heart function and a mechanical ventilator to support their breathing[7].
Newborns with asphyxia often require care in the neonatal intensive care unit (NICU)[7]. If blood loss was rapid, babies may be in shock and need fluids given through a vein, and sometimes a blood transfusion or plasma[7].
Can babies recover?
The outcome for babies with neonatal asphyxia depends on several factors, including how long the baby did not get enough oxygen and how quickly the baby received proper treatment[2].
Babies with mild or moderate asphyxia may recover fully[2]. Infants who have no or minimal brain injury may have no ongoing health problems[7].
If the cells did not get enough oxygen for a longer time, a baby may have permanent injury affecting their brain, heart, lungs, kidneys, or other organs[2]. Those who have moderate to severe brain injury may have permanent developmental issues, ranging from mild learning disorders to delayed development to cerebral palsy[7].
Most organs damaged by birth asphyxia recover over a week, but brain damage may persist in some infants[7]. In the most severe cases, asphyxia can lead to organ failure and death[2]. Some infants with severe asphyxia do not survive[7].
Possible complications
Neonatal asphyxia can cause injury to one or more organ systems in the baby’s body[7]. The most serious complication is brain damage, specifically a condition called hypoxic-ischemic encephalopathy (HIE), which refers to the neurological damage resulting from lack of oxygen and blood flow to the brain[1].
The heart may be affected, leading to poor color and low blood pressure[7]. The lungs may experience difficulty breathing and low oxygen levels[7]. Brain complications can include lethargy, seizures, or even coma[7].
The kidneys may show reduced output of urine[7]. The liver may have difficulty making proteins that are needed for blood to clot normally[7]. The intestines may have difficulty digesting milk[7]. The blood-forming system may show low platelet count and bleeding problems[7].
Long-term complications can include developmental delays, intellectual disability, physical problems such as spasticity (muscle stiffness), cerebral palsy, and epilepsy[3].
How common is this condition?
Neonatal asphyxia is a significant global health problem. The World Health Organization estimates that birth asphyxia accounts for an estimated 900,000 neonatal deaths yearly, representing 38% of deaths of children under 5 years of age[5].
Worldwide, 23% of neonatal deaths and 10% of all deaths in children under 5 years of age are estimated to occur because of birth asphyxia[15]. Neonatal asphyxia happens in 2 to 10 per 1,000 newborns that are born at term, and the rate is higher for those born prematurely[5].
Related health conditions
Neonatal asphyxia can lead to or be associated with several related health conditions. The most closely related condition is hypoxic-ischemic encephalopathy (HIE), which specifically refers to brain damage caused by oxygen deprivation and reduced blood flow[1].
Other conditions that may result from or be related to neonatal asphyxia include cerebral palsy, a group of disorders affecting movement and muscle tone caused by damage to the developing brain[3]. Seizures and epilepsy may also develop as consequences of the brain injury[2].
In preterm births, neonatal asphyxia can be a cause of intraventricular hemorrhage (bleeding in the brain)[5].
