The University has identified an alternative pain relieving drug for women in labour

A trial co-ordinated by the University of Birmingham has identified an alternative and more effective pain relieving drug for women in labour, which could significantly reduce the number of women requiring an epidural.

In the RESPITE trial, researchers at the Universities of Birmingham, Sheffield and Nottingham, compared two drugs given for pain control in labour – pethidine and remifentanil PCA. Women in established labour were randomly assigned one of the two pain killers and the researchers then assessed how many of these women later required an epidural.

Pethidine is a drug for pain relief routinely given to around a third of the 750,000 women who give birth per year in the UK and is administered via an injection.  Remifentanil PCA, which is delivered through a drip that women can control with a handheld device to give pain relief that coincides with contractions, is currently offered as standard care in very few UK hospitals.

The first and largest randomised trial of its kind, co-ordinated by Birmingham Clinical Trials Unit at the University of Birmingham and funded by National Institute for Health Research (NIHR), RESPITE involved 400 women giving birth at 14 UK hospitals between May 2014 and September 2016.

The results of the trial, published today in The Lancet, show that half the number of women in the remifentanil PCA group went on to require an epidural, compared to the pethidine group. Of the 199 women who were given pethidine, 81 (41 per cent) went on to have an epidural, compared to just 39 (19 percent) of the 201 women who were given remifentanil PCA.

Chief Investigator Dr Matthew Wilson, formerly of the University of Birmingham and now of the School of Health and Related Research (ScHARR) at the University of Sheffield, said: “While pethidine is commonly used in labour, its effectiveness in terms of pain relief has long been challenged and its shortcomings are more serious when set against known side effects which include women feeling sedated and nauseous; it can also transfer to the baby via the placenta producing side effects.

“Prior to our research it was already known that around a third of women who receive pethidine go on to have an epidural due to inadequate pain relief. 

“While epidurals provide highly effective pain relief, they lead to a higher rate of births involving the use of instruments such as forceps or suction, which can lead to women suffering further long-term health complications and needing a longer stay in hospital after birth.

“Our study has shown that remifentanil PCA is safe when given under correct supervision. More women required extra oxygen during their labour with remifentanil PCA, but there was no difference in the sedation that women felt. There was also no difference in the health of babies born to women who received remifentanil PCA, which was very reassuring.” 

The researchers now hope to see a change in national clinical guidelines to incorporate the more routine use of remifentanil PCA.

Professor Christine MacArthur, of the Institute of Applied Health Research, said: “RESPITE essentially set out to examine if there was a more effective alternative to pethidine which is safe, easy to administer and could ultimately reduce the number of women who have an epidural.

“While we were anticipating fewer women who had been given remifentanil PCA to go on to have an epidural, we did not expect to show that the epidural rate could be halved.

“The results of the trial provide strong evidence that remifentanil PCA should be routinely offered as an alternative to pethidine and should be rolled out at hospitals across the UK.

“Not only would it provide women with a more effective pain relief option in labour, it could significantly reduce the number of epidurals and the associated higher rates of instrumental births, in turn potentially reducing the financial burden on the NHS.”

The trial also found that the average pain score women reported during their labour, on a scale of zero to 100, was significantly lower in the remifentanil PCA group, and that women’s satisfaction with their pain relief and its effectiveness was significantly higher within the remifentanil PCA group compared to the pethidine group.