Vocalization during the second stage of labor to prevent perineal trauma: A randomized controlled trial

Most women suffer some degree of perineal trauma during vaginal delivery. Second stage management strategies, including vocalization, to protect the perineum have been investigated.

To compare the frequency and degree of perineal trauma at vaginal delivery, with and without use of the vocalization maneuver during the second stage of labor.

This is an open-label, randomized controlled trial. We conducted the study at the Center for Normal Deliveries of IMIP. We included low-risk women without prior cesarean deliveries. Women who met the inclusion criteria and signed the informed consent form were randomized to one of two groups: Group A (experimental) and Group B (control). A physical therapist encouraged women in Group A to maintain an open glottis during pushing and to emit sounds when exhaling (vocalization). Women in Group B underwent routine humanized vaginal deliveries. The outcomes of the study were perineal integrity and degree of perineal laceration. These were measured by the study team immediately after completion of the third stage of labor.

Women in Group A tended to have less severe perineal tear (less second and third degree lacerations) and smaller lacerations than women in group B. The vocalization maneuver reduced the risk of a perineal tear greater than 2 cm by 68% (NNT 2.2). There was no difference in other outcomes.

Encouraging women to follow a vocalization protocol coached by a physical therapist during the second stage of labor can be a helpful labor assistance technique, since this study showed that vocalization is associated with less extensive perineal tears.

This study was registered on ClinicalTrials.gov (www.

gov) registration number: NCT03605615.