Real-time imaging as visual biofeedback in active second stage of labor among nulliparas: a randomized controlled trial

Abstract

Background: A prolonged second stage of labor increases the risk of severe perineal laceration, postpartum hemorrhage, operative delivery, and poor Apgar score. The second stage is longer in nulliparas. Maternal pushing during the second stage of labor is an important contributor to the involuntary expulsive force developed by uterine contraction to deliver the fetus. Preliminary data indicate that visual biofeedback during the active second stage hastens birth.

Objective: This study aimed to evaluate if visual feedback focusing on the perineum reduced the length of the active second stage of labor in comparison with the control.

Study design: A randomized controlled trial was conducted in the University Malaya Medical Centre from December 2021 to August 2022. Nulliparous women about to commence the active second stage, at term, with singleton gestation, reassuring fetal status, and no contraindication for vaginal delivery were randomized to live viewing of the maternal introitus (intervention) or maternal face (sham/placebo control) as visual biofeedback during their pushing. A video camera Bluetooth-linked to a tablet computer display screen was used; in the intervention arm, the camera was focused on the introitus, and in the control arm, on the maternal face. Participants were instructed to watch the display screen during their pushing. The primary outcomes were the intervention-to-delivery interval and maternal satisfaction with the pushing experience assessed using a 0-to-10 visual numerical rating scale. Secondary outcomes included mode of delivery, perineal injury, delivery blood loss, birthweight, umbilical cord arterial blood pH and base excess at birth, Apgar score at 1 and 5 minutes, and neonatal intensive care unit admission. Data were analyzed with the t test, Mann-Whitney U test, chi-square test, and Fisher exact test, as appropriate.

Results: A total of 230 women were randomized (115 to intervention and 115 to control arm). The active second stage duration (intervention-to-delivery interval) was a median (interquartile range) of 16 (11-23) and 17 (12-31) minutes (P=.289), and maternal satisfaction with the pushing experience was 9 (8-10) and 7 (6-7) (P<.001) for the intervention and control arm, respectively. Women randomized to the intervention arm were more likely to agree to recommend their management to a friend (88/115 [76.5%] vs 39/115 [33.9%]; relative risk, 2.26 [95% confidence interval, 1.72-2.97]; P<.001) and more likely to have less severe perineal injury (P=.018).

Conclusion: Real-time viewing of the maternal introitus as visual biofeedback during pushing resulted in higher maternal satisfaction compared with the sham control of viewing the maternal face; however, the time to delivery was not significantly shortened.

Keywords: camera; face; live imaging; perineum; real time; second stage of labor; visual biofeedback.