Birth asphyxia describes a prolonged lack of oxygen leading up to or during birth, which can result in the baby’s brain being deprived of oxygen. Up to one in ten babies require help to breathe in the first few minutes of life, which often simply involves stimulating the baby to breathe. However, a prolonged loss of oxygen and low blood supply can cause brain damage for a newborn in as little as five minutes. The amount of damage depends on how long the baby is oxygen deprived, how low the oxygen levels go, how quickly intervention takes places and how the infants recover after oxygen supply is restored.
Also known as perinatal asphyxia, when severe this condition kills up to one million babies globally each year and is the most readily identifiable cause of cerebral palsy. Most babies who die in developing countries of severe birth asphyxia were otherwise healthy. Those with mild to moderate birth asphyxia may recover fully but in more serious cases it can cause permanent injury to the baby’s brain and other organs.
Causes of birth asphyxia
In the womb, babies need oxygen that comes via the placenta before and during birth. When oxygen supply is inadequate or interrupted due to maternal, placental or umbilical cord compromise, there is a high risk of brain damage and damage to all vital organs.
A range of complications can cause birth asphyxia including
Inadequate maternal oxygen and/or high or low blood pressure
Umbilical cord issues
Uterine wall tears
A large baby
Long or difficult birth
Serious infection in the mother or baby
Heavy maternal bleeding
Blocked or inadequately formed infant airways
Inadequate oxygen levels in the baby’s blood
Inhaling amniotic fluid and meconium (the baby’s first stool)
Anaemia in the baby.
Signs and symptoms of birth asphyxia
Before delivery the baby may have
An abnormal heart rate or rhythm
Increased acid levels in their blood.
At birth, symptoms vary and can be mild, moderate, or severe, including
A low heart rate
Weak muscle tone and/or reflexes
Bluish or pale skin, a weak cry
Absence of breathing or presence of gasping
Low blood pressure.
Birth asphyxia can develop suddenly without warning but there are risk factors. They include preeclampsia or eclampsia, water breaking more than 12 hours before delivery, fetal heart rate abnormalities, abnormal fetal birth position, pre-birth bleeding, meconium in the birth fluid, infection, prolonged labour, forceps or vacuum delivery, multiple births, low birth weight, no prenatal care, and a history of birth asphyxia.
Medical care, treatment and monitoring before and after birth can help to reduce the consequences of birth asphyxia. Please speak to your doctor or care provider about risk factors and interventions.
Birth asphyxia diagnosis
Birth asphyxia occurs around the time of birth and if moderate to severe may lead to brain damage in the newborn. This condition, diagnosed after birth, is called neonatal encephalopathy (NE) or hypoxic ischaemic encephalopathy.
Several indicators in newborns can help diagnosis at birth including
Low heart rate or absent heart-beat
Absence of breathing
Limpness or poor muscle tone
Low blood pressure
High blood lactic acid levels
Low blood pH
Doctors universally look for high lactic acid and low pH levels of less than 7.00 in the umbilical cord’s arterial blood to assess the severity of the birth asphyxia. Hours to days after birth they look for neurological problems such as seizures, poor muscle tone and brain scans (MRI and ultrasound) to determine the presence of brain injury.
The Apgar test, which is applied to infants at birth and stands for Appearance, Pulse, Grimace, Activity, and Respiration, is also useful. Babies are scored out of 10 on their skin tone, heart rate, muscle tone, reflexes and breathing. While it is not a particularly reliable indicator, a low score (0-3) for longer than five minutes can indicate birth asphyxia.
Treatment of birth asphyxia
Prompt treatment can minimise the effects of birth asphyxia and can completely avoid brain damage, particularly in less severe cases. Before birth, this may include giving the mother extra oxygen or quickly delivering the infant by an emergency caesarean if the baby has an abnormal heart beat pattern.
Immediately after birth, treatment for the infant may simply involve stimulating the baby to breathe in less severe cases. But as severity increases, the baby may require artificial breathing support and in very severe cases the infant may require both artificial breathing support and chest compressions as well as adrenaline administration.
Hudson Institute research is focused on providing support for vulnerable infants as soon as possible after birth to reduce the possibility of long-term damage. Finding ways to improve resuscitation is particularly critical in restoring cardiac function safely and rapidly.
Hours to days after birth, treatments may include reducing the baby’s internal body temperature, medication to support heart function and/or control blood pressure, intravenous nutrition, general anaesthesia to control seizures, or mechanically supporting the baby to breath.
Long term effects of severe birth asphyxia
In babies suspected to have had severe birth asphyxia, doctors or carers will monitor the baby after birth for signs of neonatal encephalopathy (NE). NE is the diagnosis of brain injury and can be defined as mild, moderate or severe.
Babies with mild to moderate NE may recover well and not suffer long term disability. Serious cases of NE can be fatal or result in conditions including brain and other organ damage, developmental delay, cerebral palsy, autism, neurological disorders, seizures, behavioural issues, attention deficit hyperactivity disorder (ADHD), mental health disorders or hearing impairment.
Our birth asphyxia research
Hudson Institute researchers are internationally known for their work in resuscitating infants who do not get enough oxygen at birth and protecting and treating the brains of these babies who are at high risk of developing conditions such as cerebral palsy.
They are investigating the transition to birth, associated breathing difficulties and the potential benefits of delaying umbilical cord clamping, which may help prevent oxygen deprivation in newborns. They are also focusing on improving treatments for infants who have suffered severe birth asphyxia.
Research by Associate Professor Graeme Polglase, outlined in this 7 News feature, has found that newborn babies who need resuscitating at birth could benefit from CPR while their umbilical cord is still attached.
Reducing brain injury in babies born following severe birth asphyxia
Pre-clinical study Scientists are developing innovative new treatments for severe birth asphyxia. Our researchers have found that applying melatonin skin patches can protect the brain against an acute lack of oxygen by reducing harmful free radicals and inflammation, and the addition of melatonin treatment to therapeutic hypothermia (which is standard care) significantly improves outcome. Our researchers are also testing whether umbilical cord blood stem cells administered after birth can reduce the progression of brain injury.
Improving the prognosis of newborns starved of oxygen
Pre-clinical studies. Professor Stuart Hooper and Professor Graeme Polglase are working to improve the initial treatment of newborn infants deprived of oxygen before birth.
They are working with Dr Calum Roberts, neonatologist at Monash Health, on investigating the possible benefits of delayed cord clamping, cord milking, improving resuscitation strategies including chest compressions and optimal ways to give adrenaline, a cardiovascular stimulant.
They ultimately aim to identify treatments which are also suitable for the developing world, where they could significantly reduce death and disability.
Pre-clinical study Most newborn babies smoothly transition to breathing outside their mother’s body. But many don’t, which can be life threatening and cause life-long problems. Professor Stuart Hooper and his team are studying the changes that occur at birth to identify factors that facilitate and impede them to reduce the risks newborn infants face.
A new anti-seizure medication for babies following severe birth asphyxia
Pre-clinical study After severe birth asphyxia babies often experience seizures, and these are strong indicators of damage to brain cells. The anti-seizure medication currently used in babies was discovered over 100 years ago, and is not very effective in infants.
Our scientists are working closely with Monash Health clinicians, Professor Rod Hunt and Professor Michael Fahey on testing an innovative new treatment for neonatal seizures, and comparing its safety and efficacy against treatments that are currently used.