Women in labour may have had their pain relief reduced unnecessarily due to an out-of-date practice, a new study suggests.
Researchers have found that epidurals do not slow labour.
There is a long-held belief that epidurals - a type of local anaesthetic - slow the second stage of labour.
Because a longer duration of this stage of labour is associated with adverse outcomes, obstetricians routinely reduce or discontinue epidural pain management in an effort to expedite this main stage of labour, researchers said.
But they suggest that this practice could be out of date.
The new study, published in the journal Obstetrics & Gynecology, found that an epidural has no effect on duration of second stage of labour - the stage which starts when a woman's cervix has dilated 10cm and ends when her baby is born - compared with placebo.
Researchers from the Beth Israel Deaconess Medical Center in Boston in the US compared the effects of low-concentration epidural anaesthetic with a saline placebo among 400 healthy first-time mothers.
"We found that exchanging the epidural anaesthetic with a saline placebo made no difference in the duration of the second stage of labour," said senior author Philip Hess, associate professor of anaesthesia and obstetrics at Harvard Medical School and director of obstetric anaesthesia at the Beth Israel Deaconess Medical Center.
"Not even the pain scores were statistically different between groups. However, pain scores in women receiving the saline placebo increased over time, as would be expected."
An epidural is an injection in the back to stop you feeling pain in part of your body.
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