Chorioamnionitis and cerebral palsy in term and near-term infants.
BACKGROUND
Half of all cases of cerebral palsy (CP) occur in term infants, for whom risk factors have not been clearly defined. Recent studies suggest a possible role of chorioamnionitis.


OBJECTIVE
To determine whether clinical chorioamnionitis increases the risk of CP in term and near-term infants.


METHODS
Case-control study nested within a cohort of 231 582 singleton infants born at 36 or more weeks' gestation between January 1, 1991, and December 31, 1998, in the Kaiser Permanente Medical Care Program, a managed care organization providing care for more than 3 million residents of northern California. Case patients were identified from electronic records and confirmed by chart review by a child neurologist, and comprised all children with moderate to severe spastic or dyskinetic CP not due to postnatal brain injury or developmental abnormalities (n = 109). Controls (n = 218) were randomly selected from the study population.


METHODS
Association between clinical chorioamnionitis and increased risk of CP in term and near-term infants.


RESULTS
Most CP cases had hemiparesis (40%) or quadriparesis (38%); 87% had been diagnosed by a neurologist and 83% had undergone neuroimaging. Chorioamnionitis, considered present if a treating physician made a diagnosis of chorioamnionitis or endometritis clinically, was noted in 14% of cases and 4% of controls (odds ratio [OR], 3.8; 95% confidence interval [CI], 1.5-10.1; P =.001). Independent risk factors identified in multiple logistic regression included chorioamnionitis (OR, 4.1; 95% CI, 1.6-10.1), intrauterine growth restriction (OR, 4.0; 95% CI, 1.3-12.0), maternal black ethnicity (OR, 3.6; 95% CI, 1.4-9.3), maternal age older than 25 years (OR, 2.6; 95% CI, 1.3-5.2), and nulliparity (OR, 1.8; 95% CI, 1.0-3.0). The population-attributable fraction of chorioamnionitis for CP is 11%.


CONCLUSIONS
Our data suggest that chorioamnionitis is an independent risk factor for CP among term and near-term infants.
Wu
Yvonne W
YW
Department of Neurology, University of California, San Francisco 94143, USA. wuy@peds.ucsf.edu
Escobar
Gabriel J
GJ
Grether
Judith K
JK
Croen
Lisa A
LA
Greene
John D
JD
Newman
Thomas B
TB
D001238:Asphyxia Neonatorum; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000145:classification / Q000453:epidemiology / Q000209:etiology*; D002821:Chorioamnionitis / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011247:Pregnancy; D012307:Risk Factors