Fever in Labour and Neonatal Encephalopathy: A Prospective Cohort Study

Abstract

Evidence suggests that both infection and fever during labor are closely associated with the later development of cerebral palsy. This seems to be the case for term as well as preterm infants. This prospective cohort study of 4915 low-risk women who entered labor at 36 to 41 weeks' gestation attempted to clarify the association between maternal fever and neonatal encephalopathy and to show whether it is independent of other intrapartum risk factors. The participants were assigned, just after amniotomy, to have or not have cardiotocographic monitoring for 20 minutes. All women in the study were thought to be at low risk of intrapartum fetal distress. Oral temperature was monitored at hourly intervals during labor, and fever was diagnosed if it exceeded 37.5°C. Intrapartum fever developed in 336 women, 6.8% of the total. Sixteen newborn infants developed encephalopathy, and seven of their mothers (44%) had maternal fever. On multiple logistic regression analysis, controlling for nulliparity, gestation, induction of labor, total length of labor, and instrumental delivery, maternal fever was significantly associated with neonatal encephalopathy; the adjusted odds ratio (OR) was 4.7. The adjusted OR for a high base deficit in the presence of maternal fever was 2.2, and for admission to the neonatal unit, 1.78. An association with cord blood acidemia, noted on univariate analysis, was no longer significant. Only 1 of the 16 neonates with encephalopathy had a positive blood culture, and only this infant and one other had an elevated C-reactive protein level. These findings indicate that maternal fever during labor is closely and independently associated with neonatal encephalopathy. Fever is, in fact, a more reliable indicator that a given fetus is at risk of encephalopathy than an abnormal cardiotocographic record. In general, these results support a role for inflammatory mechanisms in the cause of neurological morbidity in newborn infants.