Germinal matrix hemorrhage is bleeding which occurs inside the brain of a preterm baby. The germinal matrix is an area of the brain which contains many blood vessels. Babies who are born prematurely may be unable to regulate the brain's blood flow adequately, so changes in pressure may occur which burst the germinal matrix blood vessels. Bleeding can damage brain tissue, causing complications such as seizures, abnormal mental development and the neurological condition known as cerebral palsy. The outlook following a germinal matrix hemorrhage depends on the severity of the bleeding, the baby's weight and age.
A germinal matrix hemorrhage is the most potentially serious condition which may affect infants born prematurely. Full-term babies are less at risk because the germinal matrix usually disappears at around 36 weeks of age. Arteries inside the germinal matrix of preterm babies are fragile and this makes them more prone to rupture.
Normally, the blood flow through the brain is controlled by small arteries with muscular walls. Smooth muscle inside the artery walls can relax or contract to keep the brain's blood pressure constant even though pressure may be changing in the circulation through the rest of the body. In some preterm infants, this ability to regulate blood flow is lost, and a germinal matrix hemorrhage may result.
The germinal matrix is an important site for brain development because nerve cells, or neurons, are produced there which go on to form areas such as the cortex, or gray matter. That is why, even in those infants who survive a germinal matrix hemorrhage, damage in this area can sometimes go on to cause long-term problems. Hemorrhages are generally divided into four different grades, with Grade I representing the mildest and Grade IV the most severe. While only a small percentage of babies die from the milder grade hemorrhages, up to half of those with Grade IV germinal matrix hemorrhage do not survive.
Treatment of germinal matrix hemorrhage involves supporting the baby as much as possible and may involve medical care to correct blood imbalances and to maintain blood pressure. Sometimes, a condition known as hydrocephalus develops, where fluid builds up inside the skull, and surgical procedures may be necessary to drain it. As there is no cure, prevention of germinal matrix hemorrhage is very important. Preventive measures may include avoiding breathing problems at birth as far as possible, correcting blood abnormalities and protecting the baby from large changes in blood pressure.