What is brain haemorrhage in pre-term babies?
Babies born more than eight weeks prematurely (at 32 weeks of pregnancy or earlier) face several particular threats to life in their early days. One is brain haemorrhage, or the leaking of blood from the blood vessels inside the skull into the brain tissues or around them.Small bleeds are commonplace in premature babies, occurring in 10 to 15 per cent of such babies - and doctors would expect the majority to resolve with few long term problems. Most haemorrhages occur within 72 hours of birth and up to 50 per cent have no symptoms.
But if the bleeding is anything more than minor, the blood may fill the chambers of the brain called the ventricles, which are normally full of cerebrospinal fluid. These more severe ‘intraventricular’ haemorrhages or IVH cause the ventricles to swell inside the brain, putting pressure the brain tissue, and so can lead to long term brain damage.
Causes and risk factors
Bleeding occurs in preterm or premature babies primarily because their body has not developed sufficiently to function effectively outside the womb.In particular the blood vessels are small, thin and fragile and more likely to tear or split. The brain has high demands for oxygen so it requires an excellent blood supply. As a result some parts have large numbers of tiny blood vessels which penetrate the brain tissue, leaving the brain especially vulnerable to haemorrhage.
Simply being born premature is a major risk factor but the more premature the baby, the greater the risk of a significant haemorrhage into the brain, or IVH.
Anything which puts additional strain or pressure on the baby (especially on its head) can increase the risk. So a vaginal delivery, especially if it is prolonged or difficult, increases the risk of haemorrhage because the baby’s head must push and squeeze through the birth canal (a Caesarean delivery is often recommended for very premature labour).
Other complications of prematurity such as respiratory problems also increase the risk of IVH.
Symptoms
Small haemorrhages may have no symptoms, whereas a larger bleed can cause the baby to collapse suddenly. The baby may:- Stop breathing
- Become pale or blue
- Have a poor suck or high pitched cry
- Have a seizure or fit
- Become limp and floppy
- Develop a paralysis of one or more limbs
An ultrasound scan is used to make a formal diagnosis, and many premature babies are given this check during their first week.
Brain haemorrhages can cause a variety of long term complications, including severe neurodevelopmental disabilities such as cerebral palsy. Some are fatal.
Water on the brain
One potentially dangerous complication of bleeding is hydrocephalus, or ‘water on the brain’. This possibly happens because large clots or scarring resulting from the bleeding interfere with the normal flow of cerebrospinal fluid, which then begins to gather in inside the skull. Over time, this can place the brain under great pressure, and cause damage.The only treatment for hydrocephalus is an operation performed by a neurosurgeon to drain the cerebrospinal fluid, and relieve the pressure.
Treatment and prevention
The most effective strategy for IVH is to prevent premature delivery, and reduce the risk of the bleed happening in the first place. The longer the baby can be safely kept in the womb, the less likely IVH is to occur - particularly at its most severe grades.Advances in neonatal intensive care technologies and techniques have reduced the risk of IVH in recent years, and there is some medication, which, if given to the baby, may slightly reduce the chances of a bleed. However, once a premature baby has been born, and an IVH detected, doctors can do little to directly tackle the problem, and must hope that the bleeding resolves itself.
Some new research is looking at a technique to irrigate or wash out the blood filled ventricles. The treatment looks promising but it is very early days.
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