Cerebral haemorrhage is caused by immature blood vessels that can burst during a difficult birth or due to complications in a newborn baby.
Very premature babies are particularly affected by bleeding or haemorrhage in and around the brain. The risk of brain haemorrhage is greatest during the first 5 days of life.
The most sensitive parts of the brain are the areas where nerve cells formed early during the foetal stage. The cells then moved toward the cerebral cortex and left behind structures that are rich in blood vessels and bleed easily. These structures are located close to the ventricles.
The bleeding is called intraventricular haemorrhage and there are four levels of severity. The mildest form, grade 1, is restricted to the growth area and is not strictly intraventricular, i.e., no blood has entered the ventricle. With grade 2 haemorrhage, a small amount of blood has entered the ventricle, and with grade 3 the bleeding is so substantial that it fills over half of the ventricle. Grade 1-3 haemorrhage does not affect the nerve cells in the brain. Grade 4 haemorrhage, on the other hand, involves the brain tissue adjacent to the ventricles and always leads to permanent brain damage.
Grade 1–2 haemorrhages heal spontaneously and very rarely cause neurological problems in the future. After grade 3 haemorrhage, there is a risk that the baby will develop hydrocephalus and its head will increase in size rapidly (see section on hydrocephalus). Babies with grade 4 cerebral haemorrhage have a high risk of developing motor difficulties later in life.
It is standard practice at the neonatal ward to perform ultrasound examinations of the brain on all premature babies to see if there is any bleeding. The first ultrasound is performed during the baby's first few days of life and then regularly thereafter while the baby is a patient at the hospital. For babies born before week 28 of pregnancy, an MRI examination of the brain is performed around the time the baby should have been born, in order to better assess the brain's development and to ascertain if there is any permanent damage.
Cerebral haemorrhage in full-term babies is very unusual.
Text: Kajsa Bohlin Blennow