Perinatal stroke is a diverse entity that encompasses 6 different disease types. A perinatal stroke is defined as a cerebrovascular event that occurs between 20 weeks gestation and 28 days postnatal. Of note, hypoxic ischemic encephalopathy (HIE) and extra-axial hemorrhage are not classified as perinatal strokes.

The most common type of perinatal stroke is neonatal arterial ischemic stroke (NAIS). In 70%-90% of neonates with symptomatic NAIS, the initial symptom is focal seizure that occurs between 12 and 72 hours of life. Other potential symptoms include abnormal motor tone, apnea, and/or encephalopathy. Seizures may be difficult to control initially but are typically short-lived, with most infants not requiring antiseizure medication upon discharge. The exact pathophysiology is not known, but several studies have assessed maternal, fetal, and placental risk factors. Potential maternal risk factors include nulliparity, preeclampsia, and chorioamnionitis. Potential fetal risk factors include congenital heart disease, thrombophilia, 5-minute Apgar score under 7, hypoglycemia, and infection (eg, bacterial meningitis). Placental abnormalities such as severe fetal chorioamnionitis, avascular villi, or diffuse chorioamniotic hemosiderosis may be associated with increased risk of NAIS.

Arterial presumed perinatal ischemic stroke (APPIS) is presumed to be similar to NAIS in terms of underlying pathophysiology but is not detected until after 28 days of life. APPIS may account for approximately half of all perinatal arterial ischemic strokes. Most children with APPIS present with early hand preference (in the first year of life) or other focal neurologic abnormality, prompting brain imaging that reveals findings consistent with a remote arterial ischemic stroke.

Neonatal hemorrhagic stroke (NHS) is defined by accumulation of blood in the brain parenchyma, either as a primary hemorrhage or secondary transformation of an ischemic stroke. Neonates often present with seizures and encephalopathy, although large hemorrhages may lead to signs of increased intracranial pressure. Causes of NHS include structural lesions (arteriovenous malformation [AVM]; infarction) and bleeding diathesis. Various studies have assessed risk factors for idiopathic NHS; potential risk factors may be related to a difficult transition to postnatal life, although more research is needed in this area. Studies assessing the relationship with intrapartum trauma (eg, instrumental delivery) have not demonstrated a causative association.

Presumed perinatal hemorrhagic stroke (PPHS) is a rare entity diagnosed when a child presents after 28 days of life with brain imaging findings consistent with a remote parenchymal hemorrhage. Clinical presentation may include seizures, developmental delay, or early hand preference.

Periventricular venous infarction (PVI) can occur in term or preterm neonates and occurs as a result of germinal matrix hemorrhage, which typically occurs in utero prior to 32 weeks gestation. Children usually present in infancy with early hand preference or other asymmetric motor development. The leg is more likely to be involved in PVI than in arterial perinatal strokes.

Cerebral sinus venous thrombosis (CSVT) is diagnosed when a thrombus is detected in the cerebral veins or sinuses during the first 28 days of life. CSVT leads to venous infarction in approximately half of cases. Neonates often present in the first days of life with focal seizures. Symptom onset is typically later than in NAIS. Risk factors include infection (eg, sepsis, meningitis), dehydration, congenital heart disease, and mechanical compression of the venous sinuses.