Epidurals and labor progress

Erin Luben

Epidurals and labor progress

Hi Henci,

Could you share some thoughts on the research about epidurals prolonging labor by only 15-30 minutes.  From my experience as a doula, I see many labors stall for hours, regardless of how dilated the mother is when she gets it.  I have seen plenty moving fast, get an epidural at 8 cm, and then need pitocin hours later to get labor started again.   Of course, there are also those who benefit from the relief, relax, and dilate very quickly after an epidural.

I haven't done a lot of research, but I'm finding it difficult to tease out how many of these women have pitocin already or end up getting it, which would definitely have an effect on whether or not labor slows.  What are your thoughts on this?

Henci Goer

RE: Epidurals and labor progress
(in response to Erin Luben)

The most comprehensive data come from the Cochrane systematic review of epidural vs. non-epidural analgesia, which analyzes the randomized controlled trials. The review found almost no difference in length of 1st-stage labor, but the problem with the RCTs is the huge degree of crossover between arms. In most of the trials, large percentages of women allocated to the "no epidural" group had an epidural. RCT analyses keep participants with their original group regardless of the treatment they actually received ("intent to treat") because to do otherwise would undo the value of random allocation, which is that it eliminates bias. (For example, without random allocation, you can't tell whether epidurals lengthen labor or women having more difficult labors were more likely to request epidurals.) With a modest amount of crossover, analysis according to "intent to treat" is fine, but when crossover rates are high, it diminishes differences between groups. All this is a long way of saying that the trials aren't very helpful at establishing the effect of epidurals on labor duration.

I would argue, though, that the effect on labor duration isn't all that important. The real issue is: Does it affect mode of delivery? Even with the high degree of crossover, RCTs find that epidurals increase the likelihood of instrumental vaginal delivery. Among other harms, instrumental vaginal deliveries increase the likelihood of severe genital injury, including--and especially in combination with midline episiotomy--anal sphincter injury. It also increases likelihood of the woman experiencing the birth as emotionally traumatic. The RCTs don't find an increase in cesarean surgery, which is curious because epidurals have been shown to increase likelihood of persistent occiput posterior baby and need for oxytocin, both of which are associated with an increase in cesarean. I think the explanation is this: In cases where the care provider has the goal of vaginal birth whenever safely possible, having an epidural doesn't make a difference. In cases where the care provider doesn't think it matters whether the woman has a vaginal birth or a cesarean delivery, cesarean rates will be high, and again, having an epidural doesn't make a difference.

~ Henci 

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