Data abstraction.

A single pediatric nurse professional medical record analyst abstracted demographic and clinical data from electronic and traditional medical records onto standardized forms. Race/ethnicity was self-described by parents. Infarct characteristics and location were determined by review of radiology reports. Neonatal seizures were either clinically suspected or EEG-confirmed seizures that occurred within the first 28 days of life.¹³ Risk factors for perinatal AIS were defined as the following, when documented in the medical record. Operational vaginal delivery included history of forceps delivery or vacuum-assisted delivery. Primiparity included the stroke patients who were the first live birth for the mother. Hypoxic-ischemic encephalopathy included hypoxic ischemic encephalopathy or birth asphyxia. Preeclampsia included history of preeclampsia or pregnancy-induced hypertension. Chorioamnionitis included chorioamnionitis, endometritis, or maternal fever (>101°F or 38.5°C) in the 24 hours prior to delivery. Prolonged rupture of membranes was rupture of membranes >24 hours prior to delivery. Prolonged second stage of labor was a second stage of labor >2 hours. Measures of epilepsy severity included frequency of seizures and number of maintenance anticonvulsants prescribed in the month prior to last available follow-up and total number of emergency medical encounters for seizure. A neurologist reviewed all abstracted data for accuracy. Follow-up time was calculated from stroke (assumed as the time of birth) for the patients with PPIS and the acutely recognized neonatal stroke groups, and is equivalent to the age at last follow-up for both groups.