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Q In women with uncomplicated pregnancies having effective epidural analgesia in the first stage of labour, what is the effectiveness of delayed compared with early pushing?
Clinical impact ratings GP/FP/Obstetrics ★★★★★★☆ Obstetrics ★★★★★★☆
Medline, CINAHL, EMBASE/Excerpta Medica (all from inception to October 2003), the Cochrane Central Register of Controlled Trials (searched October 2003), and bibliographies of relevant papers.
Study selection and assessment:
randomised controlled trials (RCTs) of delayed versus early pushing in women having effective epidural analgesia in the first stage of labour and an uncomplicated pregnancy. Studies were assessed for allocation concealment, losses to follow up, and intention to treat analysis.
instrumental deliveries, and maternal and infant morbidity.
9 trials (2953 women) met the selection criteria. All trials included women at term with spontaneous or induced labour, effective epidural analgesia, and singleton births. Compared to early pushing, women allocated to delayed pushing had lower rates of rotational or mid-pelvic instrumental deliveries, but the groups did not differ for rates of any instrumental deliveries or second stage caesarean section (table). 3 trials (446 women) showed that delayed pushing increased duration of the second stage of labour more than early pushing (weighted mean difference 58 min, 95% CI 22 to 95 min, random effects model). 2 trials (293 women) showed no difference between delayed and early pushing on duration of pushing (weighted mean difference 1.11 min, CI –20 to 22 min, random effects model). Infant Apgar scores did not differ between delayed and early pushing.
In women with uncomplicated pregnancies having effective epidural analgesia in the first stage of labour, delayed versus early pushing reduces the risks of rotational or mid-pelvic instrumental deliveries but increases duration of the second stage of labour.
The well done systematic review by Roberts et al included 9 trials. In the Cochrane Central Register of RCTs, only 1 RCT is included on this same topic in women with no epidural use. It is unfortunate that this subject has generated such little interest.
An epidural itself alters the natural mechanism of labour. Howell1 shows that epidural use increases the rate of instrumental delivery and the incidence of malposition, which affects many women. The percentage of women with a baby not occiput-anterior (OA) at the end of labour rises from 7.3% to 16.8% with an epidural.
This systematic review is important for several reasons. When a woman labours with no epidural, delayed pushing generally means allowing the woman to decide when she wishes or can no longer resist the urge to push. An epidural appears to reduce this urge sometimes to non-existence. In this systematic review, delayed pushing was initiated at differing points varying from 1 hour to 3 hours after the discovery of full dilation, to when the head was visible, and to when the urge to push was strong.
Although the normal mechanism of rotation of the head to OA fails more often when an epidural is used, this failure may be overcome by delaying pushing. In this review, the incidence of rotational or mid-cavity forceps fell from 14% to 10%. The downside was that the duration of second stage is increased by 58 minutes. The authors describe this increased duration as “clinically important” but do not justify their statement.
Based on this review, women can be told that delayed pushing will shift 1 in 26 births from a mid-cavity to an outlet instrumental birth but will lengthen labour by 58 minutes and that it may prevent 1 caesarean delivery for every 80 women having an epidural.
For correspondence: Dr C L Roberts, University of Sydney, Sydney, New South Wales, Australia.
Source of funding: National Health and Medicine Research Council.