Risk factors for fever in labor

OBJECTIVE: To identify risk factors for fever in labor. METHODS: A retrospective case-control study was conducted. Maternal sublingual temperature was measured every 2-4 hours during labor in 3109 of 3860 consecutive term parturients presenting from September 1992 through December 1993. Women who had fever (at least one recorded temperature of 38C or more, n = 72) during labor were compared with those who remained afebrile (n = 3037). Furthermore, a matched-pair case-control study was conducted, involving 250 women at term who developed fever in labor and 250 controls matched for parity and duration of labor; all delivered between January 1989 and December 1993. A conditional multiple logistic regression analysis was used to identify independent risk factors for fever during labor. RESULTS: In the case-control study, fever was associated with epidural analgesia, nulliparity, and a long duration of labor. These three variables were also related among themselves. However, multiple regression analysis showed that all three variables were independently associated with maternal temperature. In the matched-pair study, epidural analgesia, rupture of membranes longer than 24 hours, latency phase exceeding 8 hours, and a temperature in the upper normal range (37.5-37.9C) at admission were independent risk factors for developing fever in labor. CONCLUSION: Epidural analgesia, duration of labor, and a long interval from rupture of membranes to delivery were independent risk factors for maternal fever in labor.