A study from the August issue of Anesthesiology provides evidence contrary to prior reports that fever in laboring women is associated with epidural analgesia.

In recent years, maternal temperature elevations during labor have been observed in the absence of an infection. Many have speculated about an association between maternal intrapartum fever (MIF) and several other non-infectious factors, including epidural analgesia, medications that affect body temperature, and internal and external heat production.

"Our primary research focused on studying maternal temperature individually and as a group," said lead study author Michael Frölich, M.D., M.S. "We wanted to determine whether MIF during labor is a real phenomenon and whether it is caused by non-infectious causes."

Methodology and Findings

Researchers at the University of Alabama at Birmingham investigated the potential causes of non-infectious MIF changes in 81 laboring women. All but three participants received epidural analgesia. The temperatures in the women prior to receiving epidural analgesia were compared with their temperatures after it was administered.

More than half of participants showed a small positive temperature increase. Findings showed a significant number of women with maternal temperature elevations either had a considerably longer delivery or a higher body mass index. Epidural analgesia showed no effect on MIF.

"Long labor sustains an inflammatory process that may result in a temperature elevation. Also, the same mechanism may be responsible for patients who are overweight, since the link between obesity and inflammation is well established," said Dr. Frölich.

The study authors believe future research to better identify the exact causes of non-infectious MIF will help identify and treat women who are more prone to fever during labor, including those who experience a longer delivery or have a greater body mass index.