Background: Epidural analgesia leads to increased risk of instrumental vaginal delivery (IVD). There is debate about whether or not posture in second-stage labour influences the incidence of spontaneous vaginal birth (SVB).
Objectives: In nulliparous women with epidural analgesia, does a policy of adopting an 'upright position' throughout second-stage labour increase the incidence of SVB compared with a policy of adopting a 'lying-down' position?
Design: Two-arm randomised controlled trial.
Setting: Maternity units in England and Wales.
Participants: Nulliparous women aged ≥ 16 years, at ≥ 37 weeks' gestation with singleton cephalic presentation and intended SVB, in second-stage labour with an epidural providing effective pain relief.
Interventions: (1) Upright position to maintain the pelvis in as vertical a plane as possible; and (2) lying-down position to maintain the pelvis in as horizontal a plane as possible.
Main outcome measures: The primary outcome measure was incidence of SVB. Secondary outcomes included augmentation, interventions to maintain blood pressure, duration of labour, episiotomy, genital tract trauma, post-partum haemorrhage, maternal satisfaction, neonatal metabolic acidosis, 5-minute Apgar score of < 4, resuscitation at birth and admission to neonatal unit. At 1 year for (1) women: urinary or faecal incontinence, dyspareunia and health-related quality of life; (2) for infants: major morbidity. A cost-consequences analysis with a time horizon of 1 year after the birth from a NHS perspective.
Results: Between October 2010 and January 2014, 3236 women were randomised from 41 centres in England and Wales. There was a statistically significant difference in the incidence of SVB between groups, with 35.2% of women achieving a SVB in the upright group, compared with 41.1% in the lying-down group (adjusted risk ratio 0.86, 95% confidence interval 0.78 to 0.94). There was no evidence of differences in most of the secondary maternal or neonatal outcomes, or in long-term outcomes at the 12-month follow-up. No significant overall cost differences were observed between upright and lying-down positions for mothers or their babies.
Limitations: Measurement of adherence was challenging in this unmasked trial, and adherence could be influenced by midwives' beliefs about the allocated positions. If adherence was poor, this would have diluted the difference between the two groups.
Conclusions: There is clear evidence of the benefit of adopting a lying-down position in second-stage labour in nulliparous women with epidural analgesia, with no apparent disadvantages in either short- or long-term outcomes for mother or baby, and this is cost neutral for the NHS.
Future work: Questions remain about whether or not other positions could increase the incidence of SVB further in this group of women. The results also raise questions about the role of maternal position in second-stage labour in women without an epidural.
Trial registration: Current Controlled Trials ISRCTN35706297.
Funding: This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in Health Technology Assessment, Vol 21, No. 65. See the NIHR Journals Library website for further project information.