Managing the second stage of labor: An evidence-based approach
Continuously assessing and monitoring maternal, fetal, and modifiable factors in the second stage of labor may aid clinicians in weighing the appropriateness of expectant management against operative delivery
Epidural analgesia
About 60% of women receive neuraxial analgesia in the United States,22 although rates vary widely across different populations. A Cochrane review showed no difference in the duration of the second stage among women who had early versus late initiation of epidural analgesia in labor.23 Epidural analgesia has no impact on the risk of CD; however, women with epidural analgesia experienced more hypotension, motor blockade, fever, and urinary retention.24
One management practice has been to discontinue epidural analgesia to allow resumption of sensory and motor nerve function. Another Cochrane systematic review found no difference in mode of delivery or neonatal outcomes.25 Rather than discontinuing epidural analgesia, which results in a profound increase in inadequate pain relief, one may consider titrating the dose with joint patient decision-making to allow for greater motor capability while maintaining adequate analgesia.34
Immediate vs delayed pushing
The 2 most common approaches to managing the second stage were either to initiate pushing with contractions once complete dilation occurred (immediate pushing) or to allow for a rest period in which the fetus passively rotated and descended while conserving a woman’s energy for pushing efforts (delayed pushing, laboring down, or passive descent). Since the publication of “Safe prevention of primary cesarean delivery,” however, studies have shown a concerning association between maternal and neonatal complications and prolonged second stage (which may occur with delayed pushing).3-8,35 An observational study of nearly 44,000 nulliparous women without epidural analgesia found that prolonged second stage was associated with increased chorioamnionitis, third- and fourth-degree lacerations, neonatal sepsis, neonatal asphyxia, and perinatal mortality.35
A pragmatic multicenter randomized clinical trial on the optimal management of second stage of labor across the United States recently was conducted.7 More than 2,000 nulliparous women at term in spontaneous or induced labor with epidural analgesia were randomly assigned at complete dilation to immediate pushing or delayed pushing (1 hour after complete dilation). There was no difference in the rate of vaginal delivery. The rate of postpartum hemorrhage was significantly lower among women in the immediate-pushing group compared with the delayed-pushing group (2.3% vs 4.0%, respectively; relative risk [RR], 0.6; 95% confidence interval [CI], 0.3–0.9; P = .03). Furthermore, rates of chorioamnionitis were significantly lower among women in the immediate-pushing group compared with the delayed-pushing group (6.7% vs 9.1%, respectively; RR, 0.70; 95% CI, 0.66–0.90; P = .005). No significant difference occurred in the composite outcome of neonatal morbidity between the groups. However neonatal acidemia (umbilical cord arterial pH <7.1) and confirmed or suspected sepsis were significantly increased in the delayed-pushing group.
The evidence supports active pushing at the start of the second stage. Women who consider delayed pushing should be informed that delayed pushing has not been shown to increase the likelihood of vaginal birth and that it is associated with increased risks of infection, hemorrhage, and neonatal acidemia.36
Maternal pushing position and technique
Spontaneous pushing (in which women are free to follow their instincts and generally push 3 to 5 times per contraction) versus directed pushing (women are encouraged to take a deep breath at the beginning of a contraction then hold it and bear down throughout the contraction) demonstrated no clear difference in duration of the second stage, perineal laceration, episiotomy, time spent pushing, or number of women with spontaneous vaginal birth. There was no difference in 5-minute Apgar score less than 7 or admission to the NICU.26
With regard to maternal positioning during the second stage, a Cochrane systematic review found benefits for upright posture, including a very small reduction in the duration of the second stage, reduction in episiotomy rates, and reduction in assisted deliveries.37 There was an increased risk of blood loss greater than 500 mL and possibly an increased risk in second-degree tears.37 Compared with women allocated to lying down, women in the upright position during the second stage with epidural analgesia had significantly fewer spontaneous vaginal births. There was no difference in operative vaginal delivery, obstetric anal sphincter injury (OASI), infant Apgar score of less than 4 at 5 minutes, and maternal fecal incontinence at 1 year.28
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