Epidural analgesia and intrapartum fever: placental findings

To assess whether epidural analgesia is associated with fever, independent of maternal infection, by evaluating the relationship between epidural analgesia and inflammation of the placenta.

Placentas collected prospectively from women with singleton gestations, who delivered 6 hours or more after membrane rupture, were evaluated systematically for histologic inflammation by an investigator blinded to all clinical information. Maternal and neonatal markers of infection were assessed in the cohorts who did and did not receive epidural analgesia.

One hundred forty-nine consecutive placentas were analyzed, and 80 (54%) of these women received epidural analgesia. On univariate analysis, significant differences between epidural and no epidural groups were found with respect to maternal fever 38C or greater (46% versus 26%, P = .01), placenta inflammation (61% versus 36%, P = .002), and length of labor (11.8 hours versus 9.6 hours, P = .03). The combination of maternal fever plus placental inflammation was significantly more common in the epidural group (35% versus 17% P = .02). However, maternal fever in the absence of supporting evidence of infection, in the form of placental inflammation, was not increased after epidural analgesia (11% versus 9%, P = .61).

Epidural analgesia is associated with intrapartum fever, but only in the presence of placental inflammation. This suggests that the fever reported with epidural analgesia is due to infection rather than the analgesia itself.