Perinatal stroke is a neurological event that occurs in the developing brain around the time of birth. Unlike strokes in older adults, this condition impacts fetuses and newborns, affecting approximately 1 in every 1,000 to 2,800 live births. It is the most frequent type of stroke in childhood. This event involves a disruption of blood flow that leads to brain injury. Timely recognition and management are essential for affected infants.
Defining Perinatal Stroke and Timing
The term “perinatal” specifies the timeframe during which this injury takes place, generally defined as occurring from the 20th week of gestation up to the 28th day after birth. Strokes occurring in the first 28 days of life are sometimes called neonatal strokes.
Perinatal strokes are broadly categorized into two main types based on the affected blood vessel. The most common is Arterial Ischemic Stroke (AIS), which happens when an artery is blocked, preventing oxygenated blood from reaching brain tissue. Less frequently, a Cerebral Sinovenous Thrombosis (CSVT) occurs, involving a blood clot that forms in the brain’s venous sinuses, which drain blood away from the brain.
Causes and Specific Risk Factors
The precise cause of a perinatal stroke often remains unknown, but the event is associated with various conditions that predispose the infant to clotting or disrupted blood flow. Maternal factors can increase the risk, including preeclampsia, infections, or inherited blood clotting disorders. These issues can favor the formation of blood clots within the mother’s or baby’s circulatory system.
Placental complications are also frequently linked to perinatal stroke, as the placenta acts as the life support system for the fetus. Problems such as placental infarction or abruption, where the placenta separates from the uterine wall prematurely, can lead to the formation of small blood clots that travel to the fetal circulation and eventually lodge in the brain. These clot fragments, known as emboli, are thought to be a significant cause of arterial ischemic strokes.
Neonatal or fetal risk factors include congenital heart defects, which can allow clots to bypass the lungs and travel directly to the brain. A difficult delivery resulting in birth asphyxia, or severe oxygen deprivation, is also a major risk factor. The resulting stress and changes in blood pressure can damage blood vessel linings, contributing to clot formation or vascular injury.
Recognizing the Signs and Symptoms
Recognizing a perinatal stroke can be challenging because the symptoms in newborns are often subtle and non-specific, unlike the sudden signs seen in adults. The most common acute sign is the occurrence of seizures, which typically appear between 12 and 72 hours after birth and may affect a specific part of the body. These focal seizures can manifest as repetitive twitching movements in an arm, leg, or one side of the face.
Other immediate symptoms include excessive sleepiness or lethargy, poor feeding, and a general lack of alertness. The infant may also exhibit signs of weakness or abnormal movements that favor one side of the body, a condition called hemiparesis. A significant number of perinatal strokes are not diagnosed immediately because the infant is initially asymptomatic.
When symptoms are not immediately apparent, the condition is often diagnosed retrospectively, sometimes months or years later, when developmental problems begin to emerge. Parents might first notice a consistent preference for using one hand over the other before the age of one year, known as pathological handedness. This asymmetry in motor function is a delayed indicator of weakness on the opposite side of the body, which prompts further investigation and brain imaging.
Diagnosis and Initial Medical Intervention
When a perinatal stroke is suspected, prompt neuroimaging is the immediate next step to confirm the diagnosis and determine the type and extent of the injury. Magnetic Resonance Imaging (MRI) of the brain is considered the gold standard for diagnosis in newborns. Specific MRI sequences, such as Diffusion-Weighted Imaging (DWI), are highly effective at detecting acute ischemic injury, which is essential for accurate diagnosis.
Sometimes, a Computed Tomography (CT) scan or cranial ultrasound may be used as a preliminary screen, especially if an MRI is not immediately available or if a hemorrhage is suspected. A negative ultrasound or CT scan does not definitively rule out an arterial ischemic stroke, and an MRI is typically required for precise confirmation. The imaging helps to distinguish between an ischemic blockage and a hemorrhagic bleed, which guides the acute care strategy.
Initial medical intervention focuses primarily on supportive care and preventing secondary brain injury. Immediate management includes controlling seizures with anticonvulsant medications, ensuring the baby maintains adequate oxygenation, and correcting metabolic disturbances. Unlike adult stroke treatment, clot-busting drugs (thrombolytics) are not recommended due to the unique physiology of the newborn brain and a lack of supportive evidence.
The medical team will also conduct an assessment to search for underlying causes, such as blood clotting disorders or congenital heart problems, to prevent a recurrence. Close monitoring in a neonatal intensive care unit (NICU) allows for the stabilization of the infant and the continuous observation for any signs of worsening neurological status or increased pressure within the skull.
Long-Term Outlook and Rehabilitation
The long-term outlook following a perinatal stroke is variable and largely depends on the size and location of the brain injury, as well as the brain’s capacity for plasticity. Unfortunately, most survivors experience some degree of long-term neurological consequence, with motor, cognitive, and behavioral functions potentially being affected. Perinatal stroke is recognized as the most common cause of hemiparetic cerebral palsy, which is a condition characterized by muscle weakness or paralysis on one side of the body.
Beyond motor deficits, children may face a higher risk of developing epilepsy, with nearly half of those affected experiencing seizures later in life. Cognitive and learning difficulties, speech and language delays, and issues with visual processing are also common long-term outcomes that may become more apparent as the child grows. The developing brain can sometimes reorganize functions to undamaged areas, but children often “grow into” their deficits as they reach developmental milestones that require the injured parts of the brain.
Rehabilitation and early intervention therapies are important to maximize recovery and functional independence. Physical therapy, occupational therapy, and speech therapy should be initiated as early as possible to capitalize on the brain’s neuroplasticity. These therapies focus on strengthening the affected side of the body, improving fine motor skills, and addressing language development. A multidisciplinary team approach ensures a comprehensive and tailored management strategy for the child’s developmental journey.