Objective
The aim of this systematic review and meta-analysis of randomized controlled trials was to evaluate the effect of delayed versus immediate pushing in the second stage of labor on mode of delivery and other outcomes in women with neuraxial analgesia.
Data sources
The research was conducted using MEDLINE, EMBASE, Web of Sciences, Scopus, ClinicalTrial.gov , OVID, and the Cochrane Library as electronic databases, from the inception of each database to August 2019. No restrictions for language or geographic location were applied.
Study eligibility criteria
Selection criteria included only randomized controlled trials in pregnant women randomized to either delayed or immediate pushing during the second stage of labor.
Study appraisal and synthesis methods
The primary outcome was mode of delivery. The summary measures were reported as relative risk or as mean difference with 95% confidence intervals using the random effects model of DerSimonian and Laird. An I 2 (Higgins I 2 ) value of greater than 0% was used to identify heterogeneity.
Results
Twelve randomized controlled trials, including 5445 women with neuraxial analgesia randomized to delayed versus immediate pushing during the second stage of labor, were included in the meta-analysis. Of the 5445 women included in the meta-analysis, 2754 were randomized to the delayed pushing group and 2691 to the immediate pushing group. No significant difference between delayed and immediate pushing was found for spontaneous vaginal delivery (80.9% versus 78.3%; relative risk, 1.05; 95% confidence interval, 1.00−1.10; 12 randomized controlled trials, 5540 women), operative vaginal delivery (12.8% versus 14.6%; relative risk, 0.89; 95% confidence interval, 0.75−1.08; 11 randomized controlled trials, 5395 women), and cesarean delivery (6.9% versus 7.9%; relative risk, 0.89; 95% confidence interval, 0.73−1.07; 11 randomized controlled trials; 5395 women). Women randomized to the delayed pushing group had a significantly shorter length of active pushing (mean difference, −27.54 minutes; 95% confidence interval, −43.04 to −12.04; 7 randomized controlled trials, 4737 women) at the expense of a significantly longer overall duration of the second stage of labor (mean difference, 46.17 minutes; 95% confidence interval, 32.63−59.71; 8 studies; 4890 women). The incidence of chorioamnionitis (9.1% versus 6.6%; relative risk, 1.37, 95% confidence interval, 1.04−1.81; 1 randomized controlled trial, 2404 women) and low umbilical cord pH (2.7% versus 1.3%; relative risk, 2.00; 95% confidence interval, 1.30−3.07; 5 randomized controlled trials, 4549 women) were significantly higher in the delayed pushing group.
Conclusion
In women with spontaneous or induced labor at term with neuraxial analgesia, delayed pushing in the second stage does not affect the mode of delivery, although it reduces the time of active pushing at the expense of a longer second stage. This prolongation of labor was associated with a higher incidence of chorioamnionitis and low umbilical cord pH. Based on these findings, delayed pushing cannot be routinely advocated for the management of the second stage.
Introduction
Several variables in management of the second stage of labor have been shown to influence maternal and perinatal outcomes, such as parity, use of neuraxial analgesia or of oxytocin, maternal characteristics, fetal position, and birthweight, and therefore many strategies for proper management of the second stage have been evaluated.
Why was this study conducted?
There is conflicting evidence about the effectiveness and safety of delayed versus immediate pushing in the second stage of labor.
Key findings
Delayed pushing during the second stage of labor did not affect the mode of delivery, although it reduced the time of active pushing at the expense of a longer second stage. The incidence of chorioamnionitis and low umbilical cord pH were significantly higher in the delayed pushing group.
What does this add to what is known?
Our meta-analysis shows that delayed pushing in the second stage in women with uncomplicated, singleton pregnancies and neuraxial analgesia does not affect the mode of delivery, although it reduces the time of active pushing at the expense of a longer second stage. This prolongation of labor was associated with a higher incidence of chorioamnionitis and low umbilical cord pH. Based on these findings, delayed pushing cannot be routinely advocated for the management of the second stage.
Timing of pushing in the second stage is controversial. Women can push soon after the diagnosis of complete cervical dilatation when the second stage starts, or can delay such pushing, even for 1 or more hours; however, the evidence on the effect of these 2 different approaches is conflicting. A prior meta-analysis showed that delayed pushing in women with neuraxial analgesia was associated with an increased incidence of spontaneous vaginal delivery, a reduction in the time of active pushing and with a longer second stage, whereas a recent large randomized controlled trial (RCT) did not show a significant effect of delayed pushing on the mode of delivery and instead reported an association with chorioamnionitis and postpartum hemorrhage.
Objective
The aim of this systematic review and meta-analysis of RCTs was to evaluate the effect of delayed vs immediate pushing in the second stage of labor on the mode of delivery and other outcomes in women with neuraxial analgesia.
Materials and Methods
Search strategy
This meta-analysis was performed according to a protocol recommended for systematic reviews. The review protocol was designed a priori defining methods for collecting, extracting and analyzing data. The research was conducted using MEDLINE, EMBASE, Web of Sciences, Scopus, ClinicalTrial.gov , OVID, and the Cochrane Library as electronic databases. The trials were identified with the use of a combination of the following text words: “immediate pushing” OR “delayed pushing” AND “second stage” OR “labor” AND “delivery” and randomized controlled trial as publication type, from the inception of each database to August 2019. Review of articles also included the abstracts of all references retrieved from the search. No restrictions for language or geographic location were applied.
Study selection
Selection criteria included only RCTs of pregnant women randomized to delayed vs immediate pushing in the second stage of labor. We included only RCTs reporting mode of delivery as an outcome. Quasi-randomized trials (ie, trials in which allocation was done on the basis of a pseudo-random sequence, eg, odd/even hospital number or date of birth, alternation) were excluded.
Risk of bias assessment
The risk of bias in each included study was assessed by using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. Seven domains related to risk of bias were assessed in each included trial, as there is evidence that these issues are associated with biased estimates of treatment effect: 1) random sequence generation; 2) allocation concealment; 3) blinding of participants and personnel; 4) blinding of outcome assessment; 5) incomplete outcome data; 6) selective reporting; and 7) other bias. Review authors’ judgments were categorized as “low risk,” “high risk,” or “unclear risk” of bias.
Primary and secondary outcomes
The primary outcome was mode of delivery, including spontaneous vaginal delivery (SVD), operative vaginal delivery (OVD), cesarean delivery (CD), and operative delivery (OD), defined as either OVD or CD. We also performed a post hoc subgroup analysis on SVD by duration of pushing delay. The secondary outcomes were overall duration of the second stage of labor, time of active pushing in the second stage of labor, chorioamnionitis, intrapartum fever (defined as a maternal temperature of ≥38°C), endometritis, postpartum hemorrhage (PPH) (defined as a blood loss of ≥500 mL after vaginal birth or ≥1000 mL after CD, or as defined by authors), rate of episiotomy and severe perineal lacerations (third degree or higher), low umbilical cord pH (as defined by authors), Apgar score of <7 at 5 minutes, respiratory morbidity (defined as the presence of respiratory distress syndrome, respiratory difficulties, or need for intubation), and admission to the neonatal intensive care unit (NICU).
Data extraction
Two authors (DDM, GS) independently assessed inclusion criteria, risk of bias, data extraction, and data analysis. Disagreements were resolved by discussion with a third reviewer (VB). Data from each eligible study were extracted without modification of original data onto custom-made data collection forms. Differences were reviewed, and further resolved by common review of the entire process.
Quality of the body of evidence
Overall quality of the body of evidence for the primary and secondary outcomes was assessed by using the GRADE criteria (study limitations [ie, risk of bias], consistency of effect, imprecision, indirectness, and publication bias).
Data analysis
Data analysis was completed using Review Manager 5.3 (Copenhagen: The Nordic Cochrane Center, Cochrane Collaboration, 2014). The summary measures were reported as summary relative risk (RR) or as summary mean difference (MD) with 95% of confidence interval (CI) using the random effects model of DerSimonian and Laird. An I 2 (Higgins I 2 ) value greater than 0% was used to identify heterogeneity.
Potential publication biases were assessed graphically by using the funnel plot.
The meta-analysis was reported following the Preferred Reporting Item for Systematic Reviews and Meta-analyses (PRISMA) statement.
Results
Study selection and study characteristics
A total of 5445 women with neuraxial analgesia in 12 RCTs, randomized during the first or second stage of labor to either delayed or immediate pushing during the second stage of labor, were included in the meta-analysis ( Figure 1 ). , Of the 5445 women included in the meta-analysis, 2754 (50.6%) were randomized to the delayed pushing group and 2691 (49.4%) to the immediate pushing group.
Most of the included studies used a computer-generated table of random numbers and had low to moderate risk of bias in “incomplete outcome data.” No method of blinding as to group allocation was reported ( Figure 2 ). Publication bias was not apparent by funnel plot analysis ( Figure 3 ).
Types of participants included women with uncomplicated, singleton pregnancies and vertex presentation ( Tables 1 and 2 ). Nulliparous women represented 96.3% of the sample size. All the studies included women admitted for spontaneous or induced labor at term (37−42 weeks of gestation), except 1 trial, which included women from 36 weeks of gestation. The most commonly used neuraxial technique for labor analgesia was epidural analgesia with bupivacaine, often combined with fentanyl.
| Goodfellow 1979 | Buxton 1988 | Vause 1998 | Mayberry 1999 | Fraser 2000 | Fitzpatrick 2002 | Hansen 2002 | Plunkett 2003 | Simpson 2005 | Gillesby 2010 | Kelly 2010 | Cahill 2018 | Total | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Study Location | UK | UK | UK | USA | Canada | Ireland | USA | USA | USA | USA | USA | USA | — |
| Sample size | 37 (21 vs 16) | 41 (22 vs 19) | 135 (68 vs 67) | 153 (81 vs 72) | 1862 (936 vs 926) | 178 (88 vs 90) | 252 (130 vs 122) | 202 (117 vs 85) | 45 (23 vs 22) | 77 (38 vs 39) | 59 (26 vs 33) | 2404 (1204 vs 1200) | 5445 (2754 vs 2691) |
| Population | Nulliparous; singleton; term; vertex | Nulliparous/ multiparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous/ multiparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | Nulliparous; singleton; term; vertex | — |
| Nulliparous women a | 21/21 vs 16/16 | 20/23 vs 16/19 | 68/68 vs 67/67 | 81/81 vs 72/72 | 936/936 vs 926/926 | 88/88 vs 90/90 | 64/130 vs 65/122 | 117/117 vs 85/85 | 23/23 vs 22/22 | 38/38 vs 39/39 | 26/26 vs 33/33 | 1204/1204 vs 1200/1200 | 2686/2755 (97.5%) vs 2631/2691 (97.8%) |
| Spontaneous onset of labor a | 21/21 vs 16/16 | 17/23 vs 13/19 | NR | NR | 654/936 vs 634/926 | 55/88 vs 65/90 | NR | 94/117 vs 53/85 | 0/23 vs 0/22 | 22/38 vs 21/39 | NR | 652/1204 vs 642/1200 | 1515/2450 (61.8%)vs 1444/2397 (60.2%) |
| Maternal age (mean) a | NR | 24.9 <SPAN role=presentation tabIndex=0 id=MathJax-Element-1-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 4.8 vs 23.5 <SPAN role=presentation tabIndex=0 id=MathJax-Element-2-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 4.1 | 36.1 vs 27.8 | NR | 27.6 <SPAN role=presentation tabIndex=0 id=MathJax-Element-3-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 5.0 vs 27.7 <SPAN role=presentation tabIndex=0 id=MathJax-Element-4-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 4.8 | 30 (18-40) vs 28 (18-38) | NR | 29.9 <SPAN role=presentation tabIndex=0 id=MathJax-Element-5-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 5.7 vs 29.9 <SPAN role=presentation tabIndex=0 id=MathJax-Element-6-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 6.1 | 27.2 <SPAN role=presentation tabIndex=0 id=MathJax-Element-7-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 5.7 vs 23.7 <SPAN role=presentation tabIndex=0 id=MathJax-Element-8-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 5.2 | 24.9 <SPAN role=presentation tabIndex=0 id=MathJax-Element-9-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 5.2 vs 25.4 <SPAN role=presentation tabIndex=0 id=MathJax-Element-10-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 5.1 | 28.1 <SPAN role=presentation tabIndex=0 id=MathJax-Element-11-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.0 vs 28.6 <SPAN role=presentation tabIndex=0 id=MathJax-Element-12-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 0.8 | 26.6 <SPAN role=presentation tabIndex=0 id=MathJax-Element-13-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 6.2 vs 26.5 <SPAN role=presentation tabIndex=0 id=MathJax-Element-14-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 5.9 | 28.16 vs 26.64 |
| Gestational age (mean) a | NR | 39.5 <SPAN role=presentation tabIndex=0 id=MathJax-Element-15-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.3 vs 39.8 <SPAN role=presentation tabIndex=0 id=MathJax-Element-16-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.0 | 40.19 vs 40.14 | NR | 39.4 <SPAN role=presentation tabIndex=0 id=MathJax-Element-17-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.2 vs 39.5 <SPAN role=presentation tabIndex=0 id=MathJax-Element-18-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.2 | 40.86 vs 40.57 | NR | 39.9 <SPAN role=presentation tabIndex=0 id=MathJax-Element-19-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.1 vs 40.1 <SPAN role=presentation tabIndex=0 id=MathJax-Element-20-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.2 | NR | NR | 40.8 <SPAN role=presentation tabIndex=0 id=MathJax-Element-21-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 0.3 vs 39.9 <SPAN role=presentation tabIndex=0 id=MathJax-Element-22-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 0.2 | 39.4 <SPAN role=presentation tabIndex=0 id=MathJax-Element-23-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.2 vs 39.5 <SPAN role=presentation tabIndex=0 id=MathJax-Element-24-Frame class=MathJax style="POSITION: relative" data-mathml='±’>±± ± 1.2 | 40.0 vs 39.9 |
| Neuraxial analgesia | 4-10 mL 0.25% Bupivacaine | NR | NR | 0.12-0.25 mg Bupivacaine; Fentanyl | 0.125% Bupivacaine; Fentanyl | 0.1% Bupivacaine; Fentanyl | Bupivacaine | Combined spinal-epidural b | 0.125% Bupivacaine; fentanyl | NR | 0.125% Bupivacaine; Fentanyl | NR | – |
| Oxytocin use in second stage a | 21/21 vs 16/16 | 12/23 vs 12/19 | 43/68 vs 40/67 | NR | NR | 71/88 vs 76/90 | NR | NR | 23/23 vs 22/22 | 24/38 vs 28/39 | NR | 936/1201 vs 956/1199 | 1130/1462 (77.3%) vs 1150/1452 (79.2%) |
| Definition of low umbilical cord pH | NR | Arterial umbilical cord pH <7.2 | Venous umbilical cord pH <7.25 | NR | Arterial <7.1 and/or venous <7.15 umbilical cord pH | NR | NR | Arterial umbilical cord pH <7.1 | NR | NR | NR | Arterial umbilical cord pH <7.1 | — |
| Time of randomization | At the beginning of the second stage of labor | At the beginning of the second stage of labor | During the first stage of labor or within 1 h from full dilatation | During the first stage of labor | At the beginning of the second stage of labor | At the beginning of the second stage of labor | During the first stage of labor | At the beginning of the second stage of labor | At the beginning of the second stage of labor | At the beginning of the second stage of labor | During the first stage of labor | At the beginning of the second of labor | — |
| Intervention | Delayed pushing for up to 1 h; Increase in oxytocin | Delayed pushing for up to 3 h or until the vertex became visible | Delayed pushing for up to 3 h or until the vertex became visible | Delayed pushing either after 1 h or in the presence of involuntary pressure / urge to bear down | Delayed pushing for ≥2 h unless the patient felt an irresistible urge to push or the fetal head was seen during inspection of perineum | Delayed pushing up to 1 h | Delayed pushing up to 2 h in nulliparous and 1 hour in multiparous or until the head was seen at the introitus | Delayed pushing until feeling a strong urge to push or up to 90 min | Delayed pushing until feeling a strong urge to push or up to 2 h | Delayed pushing until feeling a strong urge to push or up to 2 ho | Delayed pushing until feeling a strong urge to push or up to 90 min | Delayed pushing for 1 h or until feeling a strong urge to push | — |
| Control | Pushing immediately after diagnosis of full cervical dilatation; no increase in oxytocin | Pushing immediately after diagnosis of full cervical dilatation | Pushing within 1 h, whether the vertex was visible or not | Pushing immediately after diagnosis of full cervical dilatation | Pushing immediately after diagnosis of full cervical dilatation | Pushing immediately after diagnosis of full cervical dilatation | Pushing immediately after diagnosis of full cervical dilatation | Pushing immediately after diagnosis of full cervical dilatation | Pushing immediately after diagnosis of full cervical dilatation | Pushing within 15 min after diagnosis of full cervical dilatation | Pushing immediately after diagnosis of full cervical dilatation | Pushing immediately after diagnosis of full cervical dilatation | — |
| Main outcome | Mode of delivery | Duration of second stage | Mode of delivery | Mode of delivery | Rate of difficult delivery | Mode of delivery | Duration of second stage | Total pushing time | Fetal well-being | Total pushing time | Total pushing time | Rate of spontaneous vaginal delivery | — |
| Intention to treat | Yes | Yes | No | Yes | Yes | Yes | No | Yes | Yes | Yes | No | Yes | — |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
