What is Birth Asphyxia?
Perinatal asphyxia happens when there is a lack of blood flow or gas exchange to or from a baby just before, during, or after birth. This lack of oxygen can have serious effects on the baby’s overall health and brain function due to a lack of blood flow and oxygen to the baby during the time around birth. When the placenta (before birth) or the lungs (just after birth) can’t exchange gases like they should, or if this process stops completely, there isn’t enough oxygen getting to the vital organs. This can cause a condition where the body lacks enough oxygen (hypoxemia) and a buildup of carbon dioxide in the blood (hypercapnia). If the lack of oxygen is severe, important organs like the muscles, liver, heart, and brain won’t get enough oxygen. The body will attempt to produce energy without oxygen, which results in lactic acidosis, a condition where there’s too much lactic acid in your body. Neonatal hypoxic-ischemic encephalopathy is a specific term used to describe the effects on the brain from a lack of oxygen during childbirth.
In order to diagnose neonatal hypoxic-ischemic encephalopathy, the following factors are considered:
* Metabolic acidosis with pH less than 7.0 (in the umbilical cord or baby’s blood sample)
* Base Deficit – a measure of imbalance in the body’s acidity and alkalinity – of less than -12.
* A score of five at 10 minutes on the APGAR test, a quick assessment of the newborn’s health, with a need for more help to breathe or maintain vital signs.
* The presence of multiple organ failures.
* Signs of brain damage like a lack of muscle tone, abnormal eye or pupil movements, a weak or absent sucking reflex, difficulties with breathing, or seizures.
* The brain symptoms can’t be linked to any other cause like a metabolic disorder, genetic disorder, congenital brain disorder or the effects of medication.
What Causes Birth Asphyxia?
Perinatal asphyxia is a condition that can happen around the time of birth when a baby doesn’t receive enough oxygen. This can be caused by several factors related to the mother’s blood flow (due to a rare, serious condition called amniotic fluid embolus), the uterus (such as a rupture, which is a break or tear), or issues with the placenta or umbilical cord (like the placenta detaching too early or if the umbilical cord gets knotted or squeezed). An infection can also cause perinatal asphyxia. The oxygen deprivation may happen before the baby is born, or right after birth if the newborn is not well and needs help to start breathing.
Most of the time, perinatal asphyxia happens during childbirth. Still, about 20% of cases occur before birth, and others can take place shortly after birth. Various scenarios can lead to perinatal asphyxia. These might include the mother experiencing a sudden severe blood loss, an amniotic fluid embolism (a rare but serious condition where amniotic fluid enters the mother’s bloodstream), the placenta detaching too early (known as acute abruption), the uterus tearing (known as a rupture), or problems with the umbilical cord (like if it’s wrapped too tightly around the baby’s neck or if it comes out of the womb too soon). An infection during labor that causes the mother to have a fever can also lead to perinatal asphyxia. Doctors carefully review the mother’s pregnancy and birth history to figure out what might have caused the asphyxia.
Risk Factors and Frequency for Birth Asphyxia
Perinatal asphyxia, a condition that occurs at birth, varies in prevalence depending on the country. It affects two out of every 1000 births in developed countries. However, in developing countries, the rate can be tenfold due to limited access to care during pregnancy and after birth. Unfortunately, 15-20% of infants affected by this condition do not survive the neonatal period (the first month after birth). Moreover, up to 25% of the babies who do survive are left with long-lasting damage to their nervous system.
Signs and Symptoms of Birth Asphyxia
Perinatal asphyxia, also known as neonatal asphyxia, can lead to harmful effects on the newborn’s body, including neurological damage, issues with breathing, high blood pressure in the lungs, and dysfunction in the liver, heart, and kidneys. Based on the severity and timing of the low oxygen level, a newborn experiencing brain damage due to neonatal asphyxia can show different neurological symptoms. Doctors often use the Sarnat Staging for understanding the severity of the encephalopathy.
- In Sarnat Stage I, which is the least severe, the newborn may appear overly alert with increased periods of wakefulness, large pupils, and heightened reflexes.
- In Sarnat Stage II, the newborn might seem sluggish or unresponsive with low muscle tone, strong flexion in the distal parts of the body (hands and feet), and overall lowered body functions like small pupils, slow heart rate, and increased secretions. Seizures may also occur in this stage.
- In Sarnat Stage III, the most severe stage, the baby might show a significantly reduced level of consciousness, weak muscle tone, decreased reflexes, and extremely abnormal EEG (a test to detect electrical activity in the brain). Although seizures are less common in this stage, the brain injury is usually profound and prevents the occurrence of clinical seizures.
Testing for Birth Asphyxia
Your doctor may suggest certain tests if they think there might be issues with your baby’s health soon after birth. A chest X-ray can help determine if the baby needs help breathing or a surfactant treatment, which is a type of therapy that can help immature lungs to work better. An arterial blood gas test is beneficial in diagnosing problems with the body’s acidity or oxygen levels.
In addition, doctors can check the baby’s liver health by looking at the levels of certain enzymes in the blood, as well as the functioning of the baby’s blood clotting system. The troponin and CK-MB tests can help determine if there has been heart injury, while creatinine and blood urea nitrogen tests can assess the kidney’s health.
A newborn may rapidly use up their glucose (sugar) stores, especially if they are physically stressed, leading to significantly low blood sugar levels, a condition known as hypoglycemia. That’s why doctors recommend frequent blood sugar checks during the critical period when a newborn needs to be resuscitated.
Treatment Options for Birth Asphyxia
Therapeutic hypothermia, or cooling therapy, is a treatment used for newborn babies who have suffered from a lack of oxygen and glucose (sugar) to the brain, a condition known as neonatal hypoxic-ischemic encephalopathy. After this event happens, doctors usually observe a quiet period of up to six hours before a second phase of injury begins. During this second phase, damaged cells burst and release harmful substances into the brain.
The aim of cooling therapy is to step in during this quiet period and lessen the damage from the second phase. If started within six hours of the injury, cooling therapy can reduce death and severe disability from 62% to 48%. It can also increase the chances of survival with a normal outcome from 24% to 40%. This means that for every six to seven babies treated, one will benefit.
There are two ways to provide cooling therapy: cooling the whole body or just the head. While whole body cooling appears to be more effective at preventing death, both methods can effectively reduce severe disability and the combined risk of death and severe disability. Babies with a moderate version of the condition (referred to as Sarnat Stage II) seem to benefit most from cooling therapy. Importantly, cooling therapy doesn’t appear to reduce the number of deaths while increasing severe neurological damage in survivors.
However, cooling therapy does have potential side effects. These can include constriction of the blood vessels in the body’s outer extremities, increased urine production, heart problems, abnormal blood clotting, low blood platelets, loud breathing, white blood cell dysfunction, high blood pressure in the lungs, and fat cell death in the skin (which can lead to calcium deposits in the skin). Despite this, the therapy can be safely given using specific equipment and carefully monitored in advanced medical centers.
If babies have breathing difficulties, high blood pressure in the lungs, abnormal blood clotting, and heart dysfunction, these conditions are managed supportively. Babies with breathing difficulties and high lung blood pressure may require procedures like intubation (inserting a tube into the windpipe to assist with breathing), surfactant administration (a substance to help the lungs inflate easily), oxygen therapy, and inhaled nitric oxide treatment. Clinicians usually carefully use blood products to treat abnormal blood clotting, to improve oxygen transport, and to aid coagulation (blood clotting). Heart dysfunction might need treatment with medicines that help control blood pressure and blood flow. If the baby’s kidney function is impaired, making the baby produce less urine or no urine, fluids and blood products must be used with caution.
What else can Birth Asphyxia be?
There are several conditions and factors that can cause various health issues. These include:
- Brain tumors
- Developmental defects
- The genetics of Methylmalonic acidemia, a rare metabolic disorder
- The genetics of Propionic acidemia, another rare metabolic condition
- Infections
- Neuromuscular disorders like neonatal myopathy, a muscle disorder present at birth
