Last time we covered the INFANT trial which demonstrated no apparent benefit for “high-tech” decision support software used during childbirth. This week we look at the other end of the technology spectrum during childbirth by way of the BUMPES trial to answer the question does lying down or sitting upright during the second stage of labour with a low-dose epidural make a difference to the number of women having a normal vaginal birth?
Clinical guidelines in the UK recommend that women with an epidural should be encouraged to adopt whatever upright position they find comfortable. However, this recommendation is not based upon robust evidence from randomised trials. A 2012 Cochrane review in women without an epidural found a small reduction in the proportion requiring a vaginal delivery with instruments in the group in the upright position, but a 2017 Cochrane review in women with an epidural found no difference in the proportion of women requiring either vaginal delivery using instruments or caesarean section. The latter systematic overview was based upon five previous trials with a total of only 879 women. As pointed out by Rob Califf in his recent talk, most clinical guidelines are not based upon reliable evidence from randomised trials and this is certainly the case here and the rationale for the BUMPES trial.
The BUMPES trial involved a large (41) number of maternity units in the UK and women who received an epidural were randomised to either an upright position or lying down in the second stage of labour. The researchers recognised that a proportion of women in each randomised group might “switch allocation” (e.g. randomised to an upright position but then opting to lie down or vice versa) so the trial included an assessment of treatment adherence by regularly recording the position the women were actually in the majority of the time. A total of 3,236 women were randomised and adherence was generally good in both groups, but a larger proportion of women in the lying down switched to the upright position. Lower adherence in the lying down group might be expected given that midwives following current clinical guidelines might more often recommend more women move to an upright position from the lying down position.
The primary outcome for the trial was spontaneous vaginal birth and a clear statistically significant difference (at the 5% significance level) was found between the groups, with 35.2% (548/1,556) of women achieving spontaneous vaginal birth in the upright group compared with 41.1% (632/1,537) in the lying down group (adjusted risk ratio 0.86, 95% confidence interval 0.78 to 0.94). This represents a 5.9% absolute increase in the chance of spontaneous vaginal birth in the lying down group (number needed to treat 17, 95% confidence interval 11 to 40). No significant differences were seen in a number of the secondary outcomes, including maternal and child complications assessed at one year.
The BUMPES trial has clearly showed that a policy of adopting a lying down position in the second stage of labour in women having their first baby with epidural analgesia increases the chances of a spontaneous vaginal birth. No disadvantages were apparent to short or longer term outcomes for mother or baby. Given that current clinical guidelines in the UK favour an upright position these will need to be reviewed and updated as a result of the BUMPES trial.
The full report of the trial can be found here.