Maternal and infant characteristics associated with perinatal arterial stroke in the infant

Perinatal arterial ischemic stroke (PAS) is the most common cause of hemiplegic cerebral palsy, but its cause is not well understood, nor have risk factors been clearly defined. This case-control study was nested within acohort of 199,176 infants born in the years 1997-2002 in a managed care organization providing care to residents of northern California. Each of 40 cases, diagnosed by cranial magnetic resonance imaging or computed tomography scanning, was paired with 3 controls randomly chosen from the study population. The population prevalence of PAS was 20 per 100,000 live births. There were only 6 preterm births, and all 40 cases were singleton gestations. Nearly 60% of cases presented in the acute neonatal period. Term infants often presented with seizures. Factors found more commonly in case than in control infants included primiparity (73% vs. 44%); fetal heart rate abnormality (46% vs. 14%); emergency cesarean delivery (35% vs. 13%); chorioamnionitis (27% vs. 11%); a prolonged second stage of labor (25% vs. 4%); vacuum extraction (24% vs. 11%); cord abnormality (22% vs. 6%); preeclampsia (19% vs. 5%); and oligohydramnios (14% vs. 3%). On multivariate analysis, risk factors independently associated with PAS included a history of infertility (odds ratio [OR], 7.5; 95% confidence interval [CI], 1.3-45.0); preeclampsia (OR, 5.3; 95% CI, 1.3-22.0); prolonged rupture of membranes (OR, 3.8; 95% CI, 1.1-12.8); and chorioamnionitis (OR, 3.4; 95% CI, 1.1-10.5). The risk of PAS increased markedly in the presence of multiple risk factors. This study revealed several independent maternal risk actors associated with PAS. How these factors may affect the placenta and fetus so as to increase the risk of PAS remains to be determined.