Intraventricular hemorrhage (IVH) is a condition where bleeding occurs in the germinal matrix, a fragile area near the ventricles (fluid-filled spaces) in a premature baby’s brain. This bleeding can extend into the ventricles. Premature infants are particularly at risk because their brain structures and blood vessels are still immature and fragile.
Why does IVH happen?
There are several risk factors for IVH:
- Prematurity: The most significant risk factor for IVH is being born prematurely. Preterm infants, particularly those born before 32 weeks of gestation, have underdeveloped brain structures. The germinal matrix, a region in the brain, is highly vascularized, meaning it has a lot of blood vessels. This region is prone to bleeding because the blood vessels are immature and delicate in preterm infants. The risk of IVH is particularly high in very preterm infants. Studies show that around 1 in 4 very preterm infants may develop some degree of IVH.
- Respiratory distress: Preterm infants often experience respiratory distress syndrome (RDS) because their lungs are underdeveloped. This condition can lead to low oxygen levels, which puts additional stress on the infant’s body and brain. The mechanical ventilation that infants with RDS need to support breathing also puts stress on the body and causes changes in blood pressure.
- Unstable blood pressure: Preterm infants commonly have unstable blood pressure, which can cause fluctuations in the brain’s blood flow. These fluctuations can stress the fragile blood vessels in the germinal matrix, making them more susceptible to rupture and bleeding. Both low blood pressure (hypotension) and high blood pressure (hypertension) are problematic. Hypotension can lead to inadequate blood flow and oxygen delivery to the brain, while hypertension can cause increased pressure within the delicate blood vessels, leading to rupture and bleeding.
- Other contributing factors: Infections, both in the mother and baby, can contribute to the risk of IVH. This is because the body’s response to infection can weaken blood vessels and make them more prone to bleeding. Preterm infants may also have immature blood clotting mechanisms, which can increase the risk of bleeding in various parts of the body, including the brain. Smoking or substance use during pregnancy can also contribute to the risk of preterm birth and IVH.
When does IVH happen in infants?
More than 90% of intraventricular hemorrhage (IVH) cases occur within the first three days after birth, with approximately half of these bleeds happening within the first 24 hours. This initial period is critical for preterm infants, so many neonatal care centres will quickly implement specialized care bundles designed to protect the fragile, developing brain and prevent IVH as much as possible.
While it is rare, IVH can sometimes begin after the first week of life or even before birth. The same risk factors that contribute to early IVH apply to these less common cases. It is important to understand that even preterm infants who appear to be growing and developing well or who are >32 weeks are not entirely free from risk. The likelihood of IVH can increase significantly following episodes of infection or serious illness. These infants may need closer monitoring and follow-up to ensure any potential complications are detected and managed promptly.
How is IVH diagnosed?
In most cases, the IVH does not cause any clinical findings and is called “silent” IVH. Most bleeds are only visible on head ultrasound scans. Because premature babies are known to be at risk of developing IVH, all premature babies born before 32 weeks and some premature babies born after 32 weeks will typically have brain ultrasounds in the first week of life. Babies will then have repeat ultrasounds at regular intervals to monitor for complications of IVH.
Grades of IVH
The severity of IVH can vary. The condition is classified into grades based on the extent of the bleeding:
- Grade I: Bleeding is seen in the germinal matrix only.
- Grade II: Bleeding extends into the ventricles (fluid-filled spaces of the brain) but does not cause them to enlarge.
- Grade III: Bleeding occurs inside the ventricles and causes them to enlarge.
- Periventricular hemorrhagic infarction (PVHI; previously called “Grade IV”): Bleeding also involves the brain tissue surrounding the ventricles. It is important to note that the name Grade IV is no longer used.
Each grade of IVH impacts brain development differently and has different potential outcomes. Grades I and II IVH are often considered less severe and may have minimal long-term effects on brain development. However, babies with Grades I and II IVH still need to be carefully monitored throughout childhood.
Grade III IVH can lead to post-hemorrhagic ventricular dilation (PHVD), where the ventricles become enlarged due to the build-up of cerebrospinal fluid (CSF) that cannot be properly reabsorbed. PHVD can increase the pressure within the brain, potentially leading to further brain injury. Babies with PVHD may need interventions such as serial lumbar punctures or ventriculoperitoneal shunting to relieve the pressure.
PVHI (formerly called Grade IV IVH) is the most severe form of IVH and involves bleeding into the brain tissue itself, which can cause significant damage. PVHI can have important implications for a baby's neurodevelopment, leading to motor deficits (reduced motor or movement skills), cognitive impairments (problems with thinking and memory) and other long-term neurodevelopmental issues. PVHI can also impact a baby's overall brain development and long-term outcomes. Early detection and intervention can minimize any potential brain injury and support their overall recovery and development.
How is intraventricular hemorrhage (IVH) treated?
In most cases of mild IVH, the bleeding gradually stops, the blood vessels heal themselves, and there are no immediate treatments necessary. Once your baby is admitted to the NICU, the health-care team will initiate a comprehensive care plan that includes several key components. For IVH, interventions focus on stabilizing the baby’s condition, managing symptoms and preventing further complications. This may involve monitoring and managing blood pressure, ensuring your baby has enough oxygen and ventilation, and providing supportive care to maintain stable blood flow to the brain. In more severe IVH, treatment is focused on managing the complications that develop (PVHD and brain injury).
How to prevent IVH
Many neonatal care centres have specialized care bundles designed to protect the fragile, developing brain of preterm infants and prevent IVH as much as possible. These care bundles include several important steps to help keep babies stable and healthy. This includes minimizing how much they are handled and keeping their head in the midline position that helps blood flow properly. The babies are kept in incubators to control their surroundings, including temperature and noise, so they stay as calm and comfortable as possible. Optimal nutrition is another key part of these care bundles, with early and appropriate feeding to support their growth and prevent issues such as low blood sugar. Sometimes, certain medications, such as antenatal steroids, are given before and after birth to help reduce the chances of brain bleeding. Additionally, all staff members receive training and follow standardized procedures to ensure they provide the best care.
The NICU team will make sure that the baby's blood pressure stays steady to avoid causing any extra strain on their delicate brain. This involves closely watching their heart and blood flow and using medications if needed. The team will also carefully manage the baby's breathing by providing enough oxygen without using too much pressure. Health-care providers often use the gentlest breathing modes possible to support the preterm infant’s breathing.
What are the complications of IVH?
The complications of IVH are more likely to occur with higher grades. There are two types of complications of IVH.
- IVH may affect the flow of CSF in the ventricles causing a condition called post-hemorrhagic ventricular dilatation (PVHD).
- IVH may also cause damage to brain tissue close to the ventricles. The areas of the brain that are often affected by IVH—those adjacent to the ventricles—are responsible for important brain functions. Long-term effects of IVH will often depend on the location, extent and severity of the bleeding. Babies with severe IVH are more likely to develop neurodevelopmental impairment.
After your baby leaves the NICU, it is very important to keep up with regular check-ups at the Neonatal Neurodevelopmental Follow-Up Clinic. These visits are crucial for keeping track of your baby's growth and development. Your baby’s health-care team will schedule regular appointments to see how your baby is developing, ensuring everything is on track.
Next steps and long-term follow-up
Neonatal neurodevelopmental follow-up clinics are primarily for the surveillance of the baby’s progress in terms of their growth and development. In general, visits to a follow-up clinic are scheduled at four, eight, 12-, 18-, 24- and 36-months corrected age, meaning the age of the baby if they had been born at the expected time. Extremely premature babies and babies who experienced more serious complications may be followed more frequently and for longer periods of time.
Babies with more severe IVH may also need assessment by other specialists, including neurologists and neurosurgeons.
Follow-up visits aim to identify potential problems as early as possible. Since the long-term effects of some injuries and complications common to premature babies and babies with certain medical conditions at birth are reasonably well anticipated, regular follow-up visits provide an opportunity to identify these potential problems as they develop. This allows for intervention at the earliest possible moment. It is known that long-term effects of many complications, especially those affecting the brain, can be minimized by early therapy and other early interventions.
At SickKids
At SickKids, every baby is cared for by a large team of dedicated experts from various disciplines. This includes neonatologists, neurologists, nurses, respiratory therapists, occupational and physical therapists, social workers and other specialists. Each member of the team plays an important role in each baby’s care, bringing their expertise and compassion to support your family during this challenging time. They work closely together to provide comprehensive, coordinated care that addresses all aspects of every baby’s health and development.
