Epidurals Don’t Prolong Labour, Research Claims

Epidurals Don’t Prolong Labour, Research Claims

Epidurals are the most common form of pain relief women use during labour.

More than half of women giving birth hospital have one.

An epidural is the injection of anaesthetic into the space around the spinal cord.

The anaesthetic blocks the nerve impulses from the lower spine, and reduces the pain messages being sent to the brain.

To understand more about how epidurals work, you can read Epidural During Labour – Everything You Need To Know.

Epidurals Don’t Prolong Labour, Research Claims

However, there have been concerns about epidurals prolonging the time it takes for a mother to push her baby out.

Poor outcomes linked to epidurals include:

  • Fetal distress
  • Forceps
  • Episiotomy
  • C-section.

Women are usually advised to wait until they are in active labour or at least 5cms dilated before having an epidural.

Some care providers turn off epidurals when women are in the second stage, to prevent prolonged labour or failure to progress.

However, new research from the United State is challenging this widely held belief.

The research suggests epidurals have no effect at all on how long labour lasts.

How Was The Study Performed?

The research involved 400 healthy women giving birth to their first baby.

The first time mothers had a patient-controlled epidural analgesic pump in the first stage of labour.

All the women had pain medication during this first stage.

Once the women had reached the second stage of labour, they were randomly assigned to receive pain medication or a saline placebo.

The research was a double-blinded study. Neither the women nor their care providers knew who had received active pain medication or saline placebo.  

This type of study tends to enhance reliability and avoid bias.

Women in extreme pain were knowingly given pain medication, as directed by their obstetricians. The doctors could also choose to stop epidural infusion, based on clinical indicators.

What Did The Research Find?

The researchers found the length of the second stage was similar in both groups.

For women given active pain medication, second stage was about 52 minutes. For those with the placebo, about 51 minutes.

Of the 400 women in the study, 38 had their epidural infusions stopped by their obstetricians because of failure to progress. Of these women, 21 were in the active medication group, and 17 in the saline placebo group.

The study reported the active pain medication had no effect on:

  • The health of the newborn babies
  • Normal vaginal birth rate
  • Position of baby at birth
  • Any other measure of fetal wellbeing.

The researchers also compared pain scores reported by the women, and satisfaction with pain control.

Not surprisingly, the women who had no epidural pain medication experienced increasing levels of pain as their labour progressed.

Twice as many women given the placebo reported lower satisfaction with their pain relief, compared with those women provided with active pain medication.

What Should We Know About This Research?

It is important to note the study was very small. Also, it did not compare women who had an epidural with women who did not.

All the women in the study had an epidural during the first stage of labour. The effect of the original epidural was already in place before they had more pain relief or a placebo.

Hannah Dahlen, Professor of Midwifery at the University of Western Sydney, comments:

“This study is not saying epidural does not have an effect, as all the women had one. There wasn’t a non-epidural control which you would expect to answer this question.

“The study only showed that when they stopped the drugs in the epidural in second stage (right at the end of labour) there was not a difference in outcome, compared to if they kept the drugs in the epidural going.

“This is not saying epidural has no effect and a large Cochrane review has shown epidurals indeed do have an effect compared to no epidural”.

Do Epidurals Slow Labour Down?

There is already available evidence showing epidurals do affect the progress of labour. As Professor Dahlen mentions, the Cochrane review found there were many negative effects of epidurals, including a longer second stage of labour.

This study looked at the length of labour in 42 000 women who did or didn’t have epidurals.

The outcome of the study showed:

First time mothers with an epidural had longer second stage than those without (2.5 hours).

This is an incredibly big difference – and vastly greater than the one minute difference cited in the first study. It certainly highlights the importance of not drawing a conclusion based on one study alone.

In a normal labour, a first time mother will experience a second stage of at least one hour.

How Do Epidurals Prolong Labour?

How epidurals can slow down labour isn’t really well understood. It’s thought the epidural affects the production of oxytocin, the hormone responsible for uterine contractions.

During the first stage, levels of oxytocin increase over time. This speeds the tempo and intensity of contractions.

During the second stage, when the cervix is completely dilated, expulsive contractions push the baby from the uterus and through the vagina.

If an epidural is interfering with oxytocin levels, contractions might be less effective. Over time labour can take longer.

During the second stage, oxytocin and adrenaline are responsible for the fetal ejection reflex. This is the strong compulsive contractions which push the baby out.

However, with an epidural in place a mother might not experience the urge to push out her baby.

How Could This Research Change Things?

Senior research author Philip E. Hess, MD, Director of Obstetric Anesthesia at BIDMC, indicated while the study shows no negative effects of epidural analgesia in the second stage, it remains controversial and needs further research.

Women might feel reassured by research suggesting an epidural won’t prevent them from pushing out their baby.

However, the study doesn’t look at the differences between women who have and those who have not had epidurals. The women in this study had the same treatment until second stage.

Choosing To Have An Epidural

If you’re thinking about having an epidural, it’s important to consider all the available research.

Women who request epidurals usually do so because they are anxious about labour pain. Good birth education and support can help women to overcome this. 

Some women want an epidural because they are in excessive pain. A doula or well informed birth support person can help with coping skills during labour. 

Maternal requests for epidurals occur for many reasons, and women should know the full implications for their labour.

This small study doesn’t show us new information about the effect of epidurals on second stage. 

Rather, maternity providers should encourage women to research their options for pain relief, and to be aware of the potential risks of epidurals.

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Sam McCulloch enjoyed talking so much about birth she decided to become a birth educator and doula, supporting parents in making informed choices about their birth experience. In her spare time she writes novels. She is mother to three beautiful little humans.

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