A total of 57 RCTs (34 300 women) were eligible for inclusion in the systematic
review. The different meta-analyses used data from between
2 and 27 trials.
Gate control mechanisms (eg, water immersion and light massage)
were associated with lower levels of labour pain and less oxytocin use.
CNSC mechanisms (eg, antenatal education and continuous support)
were associated with lower rates of caesarean section, instrumental delivery,
oxytocin use, neonatal resuscitation, shorter duration of labour and
greater satisfaction with the childbirth experience. All mechanisms,
including DNIC mechanisms (eg, acupuncture, electrical stimulation and
water injections) were associated with lower rates of epidural use. There
was no evidence of a difference between any of the other primary or secondary
outcomes.
Pain as an outcome measure was only analysed in a minority of the
included studies. Substantial heterogeneity was evident for many of the
outcomes in the analysis of CNSC mechanisms. The definition of usual
care varied greatly among included studies.