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Oxygen Deprivation at Birth

Oxygen deprivation at birth occurs in 2 to 10 out of every 1,000 full-term births and more frequently in premature births, according to a study published in the American Journal of Neuroradiology. The World Health Organization additionally estimates that 4 million neonatal deaths occur annually because of oxygen deprivation.

For those children who survive, oxygen deprivation can cause significant and long-term disabilities, developmental delays, and conditions such as cerebral palsy and epilepsy.

Birth Asphyxia

Oxygen deprivation is also known as asphyxia, which is defined as a lack of oxygen and blood flow to the brain. According to the Seattle Children’s Hospital and Foundation, “birth asphyxia happens when a baby’s brain and other organs do not get enough oxygen and nutrients before, during, or right after birth.” Without oxygen and nutrients, the brain and other organs can’t work correctly.

Birth asphyxia can be divided into two major types: acute near-total asphyxia and prolonged partial asphyxia. Acute near-total asphyxia starts abruptly, typically lasts between five and 30 minutes, and causes “complete or near-complete cessation of blood flow to the fetus.” Partial prolonged asphyxia occurs more slowly, over one or more hours.

Causes

Birth asphyxia occurs for many reasons. Some causes of asphyxia before and during birth are:

  • Placental abruption (when the placenta separates from the uterus before delivery)
  • Obstruction of blood flow from the umbilical cord
  • Poor oxygen levels in the mother’s blood
  • A genetic or other fetal abnormality
  • Poor placenta function
  • The mother’s exposure to certain drugs before birth
  • Severe maternal illness or hemorrhage
  • Severe fetal infection
  • Low maternal blood pressure
  • Failure of the uterus to relax correctly during the birth process, which prevents the flow of oxygen to the placenta

According to UCSF Benioff Children’s Hospital, factors that can cause a lack of oxygen after birth may include:

• Severe anemia, or a low blood cell count
• Shock or low blood pressure
• Respiratory problems
• Cardiovascular disease

In some cases, the exact cause of birth asphyxia can not be identified.

Sign and Sympstons

Birth asphyxia, also called perinatal asphyxia, is sometimes hard to detect, with symptoms of asphyxia varying from one infant to another. However, in many cases, the affected newborn will appear pale and lifeless.

Health care professionals may need to revive the newborn immediately after delivery using a resuscitation bag and mask to push air into the lungs. Alternatively, medical staff may insert a breathing tube in the newborn’s throat. If rapid blood loss is the cause of the asphyxia, the newborn can go into shock, requiring intravenous fluids and, sometimes, a blood transfusion. Some newborns may require medications or a ventilator to help them breathe.

Symptoms of birth asphyxia include:

• Low muscle tone, poor reflexes, and a weak cry
• Having too much acid in the blood, otherwise called acidosis
• The amniotic fluid is stained with meconium, or the baby’s first stool
• Occurrences of seizures

Source: Seattle Children’s Hospital
Babies with asphyxia may also show damage to one or more organ systems, such as the heart, lung, brain, kidneys, liver, intestines, and blood-forming system.

Diagnosis

Doctors and nurses will evaluate the baby based on the appearance of their skin, heart rate, muscle tone, reflexes, and the effort required to breathe. Based on this evaluation, the baby will be given an Apgar score from 0 to 10. A low score, 0 to 3, for longer than five minutes, may indicate birth asphyxia.

Treatment

Treatment varies depending upon the symptoms and the seriousness of asphyxia. Babies with mild asphyxia receive temporary breathing support until they can breathe fully on their own.

According to Seattle Children’s Hospital, babies with more severe cases need the support of a machine to breathe and may also require nitric acid through a heart-lung pump or breathing tube. They may also need to have their body temperature lowered through hypothermia during the second stage of the disease. The hypothermia treatment is most effective in reducing brain damage if started six hours or fewer after birth and is only used on babies that are at least 35 weeks gestation.

Babies with asphyxia may require medicine to treat blood pressure or seizures, dialysis to support their kidneys, or intravenous nutrition.

Extracorporeal life support (ELCS) is an advanced treatment that uses a heart-lung pump to support the baby temporarily. The pump draws in oxygen-poor blood, removes carbon dioxide, then adds oxygen and returns the blood to the baby’s body. Babies on ECLS are sedated, and both a nurse and an ECLS specialist monitor the infant closely during the treatment.

Effects of Birth Asphyxia

Some babies who survive mild birth asphyxia will recover quickly with no long-lasting effects. Others may suffer various levels of brain damage, learning disabilities, delayed development, and other neurological disorders, such as cerebral palsy. Severe cases of asphyxia can lead to neonatal death.

Hypoxia

Hypoxia is “a state in which oxygen is not available in sufficient amounts at the tissue level to maintain adequate homeostasis.” Like asphyxia, hypoxia involves a lack of oxygen. The difference is that asphyxia is caused by injury to or obstruction of the airway, and hypoxia is due to inadequate function of the body’s tissues, including “low blood flow to the tissue or low oxygen content in the blood.” Hypoxia can be local, affecting only one part of the body, or general, affecting the entire body. Asphyxia can cause generalized hypoxia.

Hypoxia can impair the body’s metabolic activities. The body then will compensate in specific ways, including:

• Increased heart rate
• Shortness of breath, wheezing
• Sweating
• Blue discoloration of the mucosal membrane, which lines many of the body’s structures
• Skin color changes, ranging from blue to cherry red

Severe hypoxia can interfere with clotting mechanisms, which introduces the risk of excessive bleeding. According to an article in the Journal of Clinical Pathology, hypoxia has also been associated with intraventricular hemorrhage. Studies also link severe hypoxia to necrotizing enterocolitis, a dangerous condition that inflames the intestines of premature babies and may cause a hole to form in the intestines through which bacteria can enter.

HIE and Brain Damage

Hypoxic-ischemic encephalopathy (HIE) is a severe birth complication that affects full-term infants. According to an article published in Newborn and Infant Nursing Reviews, 40% to 60% of infants affected by HIE die by two years of age or have severe disabilities.

HIE can be mild, moderate, or severe. Some children experience no health issues in mild cases or only minor ones. In cases of HIE, a child may develop cerebral palsy, epilepsy, learning disabilities, or other neurological disorders. In severe cases of HIE, a child may develop a more serious disorder or, possibly, multiple neurological problems. The brain damage caused by HIE can be fatal.

Long-Term Effects of Oxygen Deprivation

While many children survive asphyxia with few effects, a lack of oxygen at birth can cause significant long-term problems for others. The brain may not recover as quickly as other organs, which typically resume normal function after treatment for oxygen deprivation.

Even a mild brain injury can have lifelong effects on a child. HIE is one cause of cerebral palsy, which the Centers for Disease Control and Prevention define as “a group of disorders that affect a person’s ability to move and maintain balance and posture.” Cerebral palsy can affect a person’s mobility, speech, vision, hearing, and learning over the long term.

Learning disabilities, such as ADHD, dyslexia, autism, and intellectual disabilities, affect children throughout their lives. Oxygen deprivation may also cause permanent blindness or visual impairments. Epilepsy, another result of oxygen loss, can become a lifelong condition.

Educational interventions can help some children with cognitive abilities improve their quality of life. Occupational and physical therapy, medications, and assistive devices also can help. Finally, in some severe cases, doctors may recommend surgery to relieve pressure on the brain for some children suffering from the long-term effects of lack of oxygen.