A drug rarely offered to women in labour is better at relieving pain than the more commonly-used alternative and makes women less likely to need an epidural, a new study suggests.
Remifentanil, a strong opioid painkiller that you can control yourself using a machine, is more effective than the commonly-used opioid pethidine, which is given to more than 250,000 women each year, according to the findings from the University of Sheffield.
A study involving 400 women found that half as many who were given remifentanil needed a subsequent epidural, compared to those who were given pethidine.
Epidurals, which are given as injections around the spinal chord, can provide total pain relief by blocking sensation, but can often lead to a forceps or vacuum delivery and more problems for mothers later down the track.
Authors say the study is the largest and most rigorous trial of its kind and found: “Remifentanil is currently offered as standard care in very few UK hospitals but could significantly reduce the number of women requiring an epidural.”
Remifentanil has some advantages compared to pethidine: remifentanil is given via a drip and women can control it themselves, while pethidine is given as an injection that lasts for up to four hours and the effects can’t be lessened once it’s been given. Both can make women feel nauseous or out of control.
All opioids pass through the placenta to a baby and can occasionally make them slower to breathe at birth, but this effect is less likely with remifentanil because the drug is active in the body for a shorter amount of time.
However, remifentanil must be given by an anaesthetist and it can’t be used for a home birth or in a midwife-led unit or Birth Centre.
Half of those involved in the trial, which was conducted across 14 maternity units, were given remifentanil while the rest were given pethidine. Some 19% of those in the remifentanil group went on to have an epidural, compared to 41% in the pethidine group.
Women given remifentanil rated their pain as less severe, and were also less likely to need forceps and vacuum during labour than women given pethidine (15% verses 26%).
However, experts have cautioned that further studies will be needed before any changes in clinical practice.
Lead author Dr Matthew Wilson, from the University of Sheffield, said the study’s findings “challenge the routine use of pethidine for pain relief during labour”.
He added: “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.
“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.
“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.”
