RESUMEN
OBJECTIVE: To determine whether visual biofeedback can be used during labor as an effective tool for shortening the second stage of labor and reducing the need for instrumental delivery. METHODS: This was a single-center randomized controlled trial. Nulliparous women under epidural anesthesia were randomized at the point of full dilation into the biofeedback group (n = 50) or the control group (n = 50). Both groups received coached maternal pushing during four consecutive contractions, while an experienced obstetrician performed transperineal ultrasound. Only women in the biofeedback group observed the ultrasound display screen. Following this intervention, labor was managed routinely by the obstetric team. Angle of progression (AOP) was measured at rest and while pushing, before and during the first and fourth contractions. Second-stage duration and delivery outcomes were compared between groups. RESULTS: Visual biofeedback did not affect the duration of the second stage, which lasted for a median of 2.28 (interquartile range (IQR), 1.25-3.10) h in the biofeedback group vs 2.08 (IQR, 1.58-3.02) h in the control group (P = 0.981). AOP was significantly higher in the biofeedback group compared with the control group, both at rest before the fourth contraction (mean ± SD, 142.6° ± 15.9° vs 136.8° ± 13.1°; P = 0.049) and while pushing during the fourth contraction (mean ± SD, 159.3° ± 19.2° vs 149.4° ± 15.1°; P = 0.005). The increase in AOP was significantly higher in the biofeedback compared with the control group between rest and pushing at the last push (mean ± SD, 16.6° ± 11.0° vs 12.6° ± 8.3°; P = 0.041) and between the first rest and last push (mean ± SD, 24.4° ± 13.6° vs 17.9° ± 11.3°; P = 0.011). The rate of intact perineum was similar between groups (12% vs 8%; P = 0.505). CONCLUSIONS: Visual biofeedback during the second stage of labor may facilitate descent of fetal head during maternal pushing without affecting second-stage duration, possibly due to the short duration of the intervention. Future studies should focus on continuous intervention throughout the second stage of labor. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.