according to the results of a randomized trial.
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“The optimal technique for managing maternal pushing during the second stage of labor is unknown,” wrote Alison G. Cahill, MD, of Washington University, St. Louis, and her coauthors, who published their study in JAMA on Oct. 9. “The two most common approaches to the second stage of labor management are to either initiate pushing with uterine contractions once complete cervical dilation occurs (immediate pushing) or to allow for spontaneous descent (delayed pushing),” they noted. “Both approaches are commonly used, and neither is considered the gold standard.”
They addressed this question in the multicenter trial of nulliparous women (mean age, 26.5 years) who, during May 2014 to December 2017, were at or past 37 weeks’ gestation and had received neuraxial analgesia. The primary outcome was the rate of spontaneous vaginal delivery; secondary outcomes included maternal and neonatal morbidity outcomes. When they reached complete cervical dilation, women were randomized to immediate pushing or delayed pushing, in which they were instructed to wait 60 minutes.
The study was terminated after the data and safety monitoring board conducted a planned interim analysis; the analysis found futility in the delayed pushing group and raised concerns about increased morbidity in that group.
Among the 1,031 women in the immediate pushing group, the rate of spontaneous vaginal delivery was 85.9%; the rate was 86.5% among the 1,041 women in the delayed pushing group (P = .67).
The mean duration of the second stage of labor was significantly shorter in the immediate pushing group (102.4 minutes), compared with that seen in the delayed pushing group (134.2 minutes; P less than .001). The mean duration of active pushing was significantly longer in the immediate pushing group (83.7 minutes), compared with that seen in the delayed pushing group (74.5 minutes; P less than .001).
Dr. Alison G. Cahill
In terms of secondary outcomes, rates of postpartum hemorrhage were lower in the immediate pushing group (2.3%), compared with the rate among those in the delayed pushing group (4%; P = .03). During the second stage of labor, chorioamnionitis was significantly more common among women in the delayed pushing group (9.1%), compared with rate among women in the immediate pushing group (6.7%; P = .005). There was no significant difference between the two groups in the rates of a composite neonatal morbidity outcome (which included birth injury, respiratory distress, and neonatal acidemia), which was 7.3% in the immediate pushing group and 9.9% in the delayed pushing group. There were no neonatal deaths.
Among prespecified exploratory outcomes, the rates of neonatal acidemia and suspected neonatal sepsis were significantly higher in the delayed pushing group, whereas the rate of third-degree perineal lacerations was significantly higher in the immediate pushing group.
“The finding of no effect on spontaneous vaginal delivery for pushing timing during the second stage of labor and the evidence suggesting increased maternal and neonatal complications in the delayed pushing group support the view that women immediately pushing after complete cervical dilation may be preferred because women without neuraxial analgesia reflexively push immediately,” the authors pointed out. Their results, they concluded, “may help inform decisions about the preferred timing of second stage pushing efforts when considered with other maternal and neonatal outcomes.”
They noted that the trial had several limitations, including the unblinded design, which raised the possibility of bias that may have influenced the management of patients or diagnoses.
The authors had no disclosures. The study was supported by a grant from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and by funding from the department of obstetrics and gynecology at Washington University, St. Louis.
SOURCE: Cahill AG et al. JAMA. 2018;320(14):1444-54.