Vocalization and Spontaneous Pushing in the Second Stage of Labor

February 20, 2026 updated by: Yasemin Dincel, Istanbul University - Cerrahpasa

The Effect of Vocalization and Spontaneous Pushing Techniques Used in the Second Stage of Labour on Birth Outcomes: A Randomised Controlled Trial

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.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

112

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Ataşehir
      • Istanbul, Ataşehir, Turkey (Türkiye), 34758
        • Istanbul University Cerrahpasa

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria for the Study:

  • Being 18 years of age or older
  • Being nulliparous
  • Being at term (between 38 and 42 weeks of gestation)
  • Expecting a vaginal delivery
  • Having a singleton pregnancy
  • Presenting in vertex position
  • Estimated fetal weight between 2500-4000 g
  • Having had a complication-free pregnancy in terms of both mother and fetus
  • Not having any perinatal risks
  • Not having received any analgesia or anesthesia to relieve pain and fatigue during labor
  • Being able to read, understand, and write Turkish
  • Voluntarily agreeing to participate in the study

Exclusion Criteria:

  • Being multiparous
  • Having a multiple pregnancy
  • Having dysphonia and hearing loss
  • Being a high-risk pregnant woman
  • Having any systemic, chronic, or neurological disease
  • Pregnant women with fetal risk (presentation anomaly, cephalopelvic disproportion, macrosomia, SGA, fetal death, fetus without gross pathology according to ultrasound)

Endpoints for Cases Included in the Study:

  • Loss of the baby during labor or delivery
  • Delivery by cesarean section
  • Pharmacological intervention to relieve pain and fatigue during labor

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: ARM 2
No specific instructions will be given regarding how the mother should push during the second stage of labor.
Experimental: ARM 1
During the second stage of labor, vocalization pushing techniques (using the vowels A, O, and U to exhale in deep tones) will be encouraged, and the mother's pushing will be observed.
Procedure: The vocalization straining technique will be used.
During the second stage of labor, vocalization pushing techniques (using the vowels A, O, and U to exhale in deep tones) will be encouraged, and the mother's pushing will be observed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Visuel Analog Scale -Pain
Time Frame: When cervical dilation is 8-9 cm and within the first 30 minutes after delivery
Min: 0- Max:10
When cervical dilation is 8-9 cm and within the first 30 minutes after delivery
Birth Experience Scale
Time Frame: When cervical dilation is 8-9 cm and within the first 30 minutes after delivery
Min: 42- Max:150
When cervical dilation is 8-9 cm and within the first 30 minutes after delivery
Visual Analogue Scale for Fatigue
Time Frame: When cervical dilation is 8-9 cm and within the first 30 minutes after delivery
Min: 0- Max:10
When cervical dilation is 8-9 cm and within the first 30 minutes after delivery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Istanbul University - Cerrahpasa

Investigators

  • Principal Investigator: Yasemin Dinçel, Istanbul University - Cerrahpasa

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 15, 2025

Primary Completion (Actual)

March 20, 2025

Study Completion (Estimated)

March 15, 2026

Study Registration Dates

First Submitted

December 19, 2025

First Submitted That Met QC Criteria

January 2, 2026

First Posted (Actual)

January 5, 2026

Study Record Updates

Last Update Posted (Actual)

February 24, 2026

Last Update Submitted That Met QC Criteria

February 20, 2026

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 26.2025fbu

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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