Epidural analgesia in labor and fetal hyperthermia.

Abstract

To assess the effect of epidural analgesia on fetal temperature in labor, contrasting intrauterine with oral thermometry. Fetal skin and maternal uterine wall temperatures were measured with an intrauterine probe in 57 laboring women at term. Maternal oral temperatures were measured in the normal way by birth attendants unaware that their measurements would be examined. Maximum recorded fetal, uterine, and oral temperatures were compared. Epidural analgesia resulted in a significant fetal temperature rise compared with other methods of analgesia. Duration of epidural analgesia correlated with the fetal temperature (R = 0.44, P = .012). Oral thermometry underestimated fetal temperature in 95% of the studies. We estimate that 5% of fetuses reached a core temperature in excess of 40C in this study, all in association with epidural analgesia. We suggest that antipyretic measures be considered after 5 hours of epidural analgesia in ambient temperatures above 24C.