Last updated November 6, 2018 at 4:04 pm
UK study suggest switching standard pain relief drug, pethidine, to remifentanil to bring greater relief to mothers.
Childbirth can be a painful and dangerous process. Epidurals can often bring relief but due to side effects is not always the first line of treatment for pain relief.
Epidurals are injections of pain relief drugs around the spinal cord. Whilst effective, they can increase the need for instrumental delivery during birth, which comes with its own potential long-term side effects for the mother, such as risk of physical trauma, incontinence, and sexual dysfunction.
There are a number of other drugs that are used as alternatives, such as pethidine and remifentanil, with the former being the standard first line option.
In a trial of 400 women from around the UK, researchers found that remifentanil could half the number of women needing an epidural.
It could potentially open up improved standards of care during labour.
Better or worse
Although pethidine is more widely used, “previous studies have shown that at least one in three women given pethidine to manage pain during labour require a subsequent epidural as the drug is not always effective,” says lead author Dr Matthew Wilson, University of Sheffield, UK.
“It also has unwanted side effects such as sedation and nausea for the mother, and it may pass into the baby’s bloodstream through the placenta.”
Halving the need for epidurals
In the study, women in labour were randomly assigned pethidine – the current standard of care – or remifentanil, both with the option for an epidural if the pain relief was insufficient.
Due to the way the drugs are administered, study participants were not hidden from the treatment they received. Remifentanil was given as a patient-controlled drip and women could receive 40µg of the drug every two minutes by pressing a hand held device, whereas pethidine was given as an injection of 100mg of the drug into a muscle up to every four hours with a maximum of 400mg in 24 hours.
They also had the option to request an epidural before their assigned drug could be administered. Once a women requested an epidural, it would have been unethical to withhold it.
Half as many women in the remifentanil group went on to have an epidural (19%) than in the pethidine group (41%). This result remained the same even when the women who did not receive the drug they were meant to were excluded.
On average, women in the remifentanil group rated their pain as less severe than women in the pethidine group. They also experienced greater satisfaction with their pain relief compared to pethidine.
Women given remifentanil were also less likely to need forceps and vacuum during labour than women given pethidine (15% vs 26%).
However, remifentanil was associated with twice as many mothers having low oxygen levels than pethidine (14% vs 5%), and more women in the remifentanil group were given supplementary oxygen. Whilst the authors are optimistic about their results, they caution that more research needs to be carried out to understand this.
Sweet, sweet relief
There are a number of reasons that those in labour may want an epidural. The author’s acknowledge that the higher number of women seen in the pethidine group immediately requesting an epidural could be due to preconceptions about pethidine’s effectiveness.
“Our findings challenge the routine use of pethidine for pain relief during labour. Remifentanil reduced the need for an epidural by half and there were no lasting problems for the mothers and babies in our trial, although the effect of remifentanil on maternal oxygen levels needs to be clarified in further studies,” says Wilson.
Using a more effective pain relief drug like remifentanil would reduce the need for epidurals, instrumental deliveries and any associated co-morbidities.
Now that’s a relief for any future mothers.