Warming epidural local anaesthetic cut intrapartum fever

Design

Double-blind randomised controlled trial

Population

220 nulliparous women receiving epidural labour analgesia

Primary outcome

Incidence of intrapartum fever (38 degrees or more)

Effect

Fever 15.5% vs 30.9%, relative risk 0.5 (95% CI 0.30 to 0.84)

Epidural labour analgesia is associated with intrapartum fever, which triggers maternal and neonatal sepsis evaluations. This double-blind randomised trial in 220 nulliparous women tested whether warming the local anaesthetic to body temperature reduces it, comparing 0.075% ropivacaine with sufentanil at 37 degrees against the same solution at 22 degrees.

Fever (temperature of 38 degrees or more) occurred in 15.5% of the warmed group versus 30.9% of the room-temperature group — a relative risk of 0.5 (95% CI 0.30 to 0.84). Maximum temperature was also modestly lower. However, the 50% reduction fell short of the 60% the trial had set as clinically meaningful, and shivering, labour duration and neonatal outcomes did not differ.

Warming the solution is a simple, low-cost adjustment that approximately halved fever incidence here. It is a reasonable step where epidural fever and its downstream workups are a concern, with the caveat that this single trial did not meet its own prespecified bar.

• Double-blind randomised trial, 220 nulliparous women, warmed (37 degrees) vs room-temperature (22 degrees) epidural solution.
• Intrapartum fever occurred in 15.5% vs 30.9%; relative risk 0.5 (95% CI 0.30 to 0.84).
• Maximum temperature was modestly lower with warming (median difference 0.2 degrees).
• Shivering, labour duration and neonatal outcomes did not differ.
• The 50% reduction fell short of the trial's preset 60% threshold for clinical meaningfulness.

Why it matters

Epidural-associated fever drives maternal and neonatal sepsis workups, so a simple way to reduce it has downstream value.

Don't overread it

A single-centre trial that did not meet its prespecified threshold; it supports warming as reasonable, not as established practice.

The statistics, in plain English

A relative risk of 0.5 with an interval below 1.0 is a real halving of fever; the result is statistically significant but missed the larger effect the trial was designed to detect, so the benefit may be smaller than hoped.

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