BackgroundThere are concerns about the harmful effects of the Valsalva maneuver during the second stage of labor.ObjectivesComparing the effects of spontaneous pushing in the lateral position with the Valsalva maneuver during the second stage of labor on maternal and fetal outcomes.MethodsInclusion criteria in this randomized clinical trial conducted in Iran were as follows: nulliparous mothers, live fetus with vertex presentation, gestational age of 37 - 40 weeks, spontaneous labor, and no complications. The intervention group pushed spontaneously while they were in the lateral position, whereas the control group pushed using Valsalva method while in the supine position at the onset of the second stage of labor. Maternal outcomes such as pain and fatigue severity and fetal outcomes such as pH and pO2 of the umbilical cord blood were measured.ResultsData pertaining to 69 patients, divided into the intervention group (35 subjects) and control group (34 subjects), were analyzed statistically. The mean pain (7.80 ± 1.21 versus 9.05 ± 1.11) and fatigue scores (46.59 ± 21 versus 123.36 ± 43.20) of the two groups showed a statistically significant difference (P < 0.001). Moreover, the mean duration of the second stage in the intervention group was significantly higher than that in the control group (76.32 ± 8.26 minutes versus 64.56 ± 15.24 minutes, P = 0.001). The umbilical cord blood pO2 levels of both groups showed a statistically significant difference (28.29 ± 11.76 versus 18.83 ± 9.86, P < 0.001), whereas their pH levels were not significantly different (P = 0.10).ConclusionsSpontaneous pushing in the lateral position reduced fatigue and pain severity of the mothers. Also, it did not worsen fetal outcomes. Thus, it can be used as an alternative method for the Valsalva maneuver.