A stroke occurs when blood flow to a part of the brain is interrupted, either by a blockage or a rupture of a blood vessel, causing brain injury. A perinatal stroke is this same event, but it happens specifically around the time of birth, affecting a developing fetus or newborn infant. This brain injury can have lasting effects, impacting movement, learning, and behavior as the child grows. Perinatal stroke is a leading cause of neurological disability in children.
Defining the Perinatal Stroke Timeframe and Types
The “perinatal” period is a specific window that begins in the late stages of pregnancy and extends shortly after birth. This timeframe generally spans from the 20th to the 28th week of gestation through the 28th day of postnatal life. Strokes that occur within this period are classified based on the mechanism of injury to the brain’s blood vessels.
The two primary categories are Ischemic Stroke and Hemorrhagic Stroke. An Ischemic Stroke, such as Perinatal Arterial Ischemic Stroke (PAIS), occurs when a blood clot blocks a vessel, cutting off the blood and oxygen supply to a region of the brain. Conversely, a Hemorrhagic Stroke involves the rupture of a blood vessel, causing bleeding into the brain tissue.
The timing of the injury also helps categorize the stroke: prenatally (fetal stroke), during the birth process (intrapartum), or in the first four weeks of life (neonatal stroke). Arterial Ischemic Stroke is the most common form, with an estimated incidence of about 1 in 4,000 live births. Some strokes may not produce noticeable symptoms at birth and are only diagnosed months or years later when developmental delays become apparent; these are often referred to as presumed perinatal strokes.
Identifying Causes and Risk Factors
The cause of a perinatal stroke is often not definitively known, but a combination of factors can increase the risk. Maternal conditions that affect the pregnancy environment are one set of risk factors. These include pre-eclampsia, which involves high blood pressure and organ damage, and infections like chorioamnionitis, an inflammation of the fetal membranes.
The placenta, which provides oxygen and nutrients to the fetus, can also be a source of risk if it is abnormal or insufficient. Placental disorders like placental abruption, where the placenta separates from the uterine wall too early, can disrupt blood flow. In many cases, the placenta is suspected to be the source of a blood clot that travels to the fetal brain.
Complications that arise around the time of delivery can also contribute to the risk. These may involve birth trauma, mechanical injury to the head or neck, or a lack of oxygen, known as birth asphyxia. Fetal conditions, such as congenital heart disease or specific blood clotting disorders, are also associated with a higher likelihood of perinatal stroke.
Recognizable Signs and Diagnostic Methods
Recognizing the signs of a perinatal stroke in a newborn can be challenging because the symptoms are often subtle and non-specific. The most common sign in the acute neonatal period is the occurrence of seizures. These seizures are typically focal, affecting only one part of the body, such as repetitive twitching in an arm or leg, and usually appear between 12 and 72 hours after birth.
Other initial signs can include general neurological difficulties, such as lethargy, poor feeding, or poor muscle tone (hypotonia). In some instances, the signs are not immediately obvious and only become apparent months later when the child begins showing motor asymmetry. This asymmetry, such as favoring one hand much earlier than is typical or noticeable weakness on one side of the body, can be a delayed indicator of an injury that occurred around birth.
Diagnosis relies on specialized brain imaging to confirm the injury and its location. While a cranial ultrasound or computed tomography (CT) scan may detect an acute stroke, Magnetic Resonance Imaging (MRI) is considered the best method for confirming the diagnosis and determining the extent of the injury. Specific MRI techniques, such as magnetic resonance angiography (MRA) and magnetic resonance venography (MRV), can also be used to visualize the arteries and veins to identify blockages or ruptures.
Management and Long-Term Outlook
Acute management of a perinatal stroke primarily involves supportive care to stabilize the newborn. This includes managing immediate complications, such as using anticonvulsant medications to control seizures. For a hemorrhagic stroke, surgery may be necessary to remove pooling blood and reduce pressure on the brain.
Long-term management focuses on neurorehabilitation to maximize the child’s functional abilities. Early intervention services are initiated soon after diagnosis, including physical therapy, occupational therapy, and speech therapy. These therapies leverage the developing brain’s plasticity—its ability to rewire itself—to help recover function in the areas affected by the stroke.
The long-term outlook for children who have had a perinatal stroke is highly variable, depending on the stroke’s severity and location. A significant number of survivors will experience lifelong neurological issues. The most common long-term complication is cerebral palsy, specifically weakness on one side of the body (hemiparesis). Other potential complications include epilepsy, cognitive and learning difficulties, and language delays. Early and consistent rehabilitation can significantly improve outcomes and quality of life.