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.
However, maternal care providers have long been concerned about epidurals prolonging the time it takes for a mother to push her baby out.
A longer pushing stage is linked to poor outcomes such as fetal distress, forceps delivery, episiotomy and c-section.
Women are usually advised to wait until they are in active labour or at least 5cms dilated before having an epidural.
Many obstetricians will turn off epidurals, or reduce the dosage, while women are in the second stage, to prevent prolonged labour or failure to progress.
Epidurals Don’t Prolong Labour, Research Claims
New research from the United States, however, is challenging this widely held belief, suggesting epidurals have no effect at all on how long labour lasts.
What Did The Research Find?
Scientists at Beth Israel Deaconess Medical Center (BIDMC) believe their research shows the practice of delaying epidurals until a certain point could be outdated and misguided.
The research, published in the journal Obstetrics & Gynecology, involved 400 healthy women giving birth to their first baby.
The first time mothers were provided with a patient-controlled epidural analgesic pump in the first stage of labour, and given active pain medication during this early stage.
Once the women had reached the second stage of labour, they were randomly assigned to receive either pain medication or a saline placebo.
The study was double-blinded, which means neither the women nor their care providers knew whether they had received the active pain medication or the 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.
The researchers found the duration of the second stage was similar in both groups. For women given active pain medication, it 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, or 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 whose epidural pain medication was halted 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 BIDMC study was very small. Also, it failed to 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. It wasn’t until they reached the second stage they were randomly assigned to have active pain medication or a saline placebo. The effect of the original epidural was already in place.
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”.
Typically, when a woman has an epidural during active labour, the medication wears off around the second stage, so she is able to push actively. This is likely to have occurred in the case of the women in the saline placebo group.
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 was startling: first time mothers who had an epidural took almost 2.5 hours longer to go through the second stage than women who didn’t have an epidural.
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 physiological labour, a first time mother will experience a second stage of at least one hour. Prolonged second stage is usually associated with adverse outcomes for both mother and baby.
However, the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) have issued guidelines stating labouring women should have additional time to push, considering vaginal birth rates are high and overall rates of complications are low.
How epidurals can slow down labour isn’t really well understood. It is 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 level, contractions might be less effective, and over time labour can take longer.
During the second stage, oxytocin and adrenaline are responsible for the fetal ejection reflex, the strong compulsive contractions which push the baby out.
With an epidural in place, however, a mother might not experience the irresistible urge to push out her baby and have to rely on adrenaline instead.
How Could This Research Change Things?
Senior research author Philip E. Hess, MD, Director of Obstetric Anesthesia at BIDMC, has 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 in the second stage, between women who have and those who have not had epidurals.
If women are deciding whether or not to have an epidural, they should take into consideration the other research which clearly indicates a longer second stage.
Women who request epidurals usually do so because they are anxious and fearful of labour pain. They might have little knowledge or support to overcome their fear.
Other women might opt to have an epidural because they are experiencing excessive pain, which can occur when they aren’t being well supported or experiencing hostile care.
An epidural may be considered in some situations – when labour is very long, or the mother is too exhausted to continue. She might need good quality rest and be able to continue to labour once the epidural has worn off.
Maternal requests for epidurals occur for many reasons, and women are entitled to know the full implications for their labour.
This small study isn’t grounds for suggesting previous guidelines for epidural use are outdated or misguided. Rather, maternity providers should be working further to encourage women to research their options for pain relief, and to be aware of the potential risks of epidurals.