Vocalization and Spontaneous Pushing in the Second Stage of Labor

The second stage of labor, defined as the period from full cervical dilatation to fetal birth, is a critical phase in which maternal pushing techniques may significantly affect maternal and neonatal outcomes (1-5). Evidence indicates that directed Valsalva pushing may be associated with maternal apnea, increased fatigue, pelvic floor injury, and adverse fetal effects, whereas spontaneous pushing with an open glottis supports physiological birth processes (2,5-11). The World Health Organization recommends encouraging women to follow their natural pushing urges and supports the use of open-glottis pushing techniques to promote a positive childbirth experience (12). Vocalization pushing is an open-glottis maneuver involving intentional low-tone sound production during exhalation, which may facilitate pelvic floor relaxation, improve pain management, and enhance the birth experience (9-11). However, evidence regarding the effectiveness of vocalization pushing is limited, and data from Türkiye are lacking. This randomized controlled clinical trial aims to evaluate the effects of vocalization and spontaneous pushing techniques during the second stage of labor on labor duration, pain intensity, perineal trauma, maternal fatigue, and childbirth experience.

The second stage of labor begins with complete cervical dilatation and continues until the birth of the fetus. During this phase, important physiological events occur, including increased contraction frequency and intensity, fetal descent, and rotation through the birth canal (2,5). Pushing is a physiological response that facilitates fetal expulsion through coordinated uterine contractions and maternal effort (2,5). Two primary pushing techniques are described in the literature: Valsalva pushing, characterized by breath-holding with a closed glottis, and spontaneous pushing, performed with an open glottis following the woman's natural urge (2,3,5-9). Studies report that Valsalva pushing may lead to maternal apnea, increased fatigue, fetal head compression, pelvic floor damage, and impaired bladder function (2,7,10,11). In contrast, open-glottis pushing techniques have been associated with reduced maternal and fetal distress, protective effects on the perineum, decreased labor pain, shorter second-stage duration, higher Apgar scores, improved umbilical cord pH values, and greater maternal satisfaction (5,6,10-14). Vocalization pushing, defined as intentional low-tone sound production (e.g., "A," "O," or "U") during exhalation, is a maneuver aimed at maintaining an open glottis during pushing (10,11). Evidence suggests that vocalization during childbirth may promote pelvic floor relaxation, reduce the severity of perineal lacerations, improve pain coping through vibrational effects, and contribute to a more positive and empowering birth experience (9-12). Despite these potential benefits, the literature contains limited high-quality evidence regarding vocalization pushing, and no clinical studies have examined its use during the second stage of labor in Türkiye. This randomized controlled trial will compare vocalization pushing and spontaneous pushing techniques during the second stage of labor. Eligible women will be randomly assigned to either the vocalization pushing group or the spontaneous pushing group. Outcomes will include duration of the second stage of labor, pain intensity, perineal trauma, maternal fatigue, and childbirth experience. The findings are expected to support evidence-based, physiological, and woman-centered intrapartum care practices.