Evaluation the effect of fundal pressure during labor on anal sphincter by 3D transperineal ultrasound

Aim: To investigate the association between application of fundal pressure during the second stage of labor (Kristeller maneuver) and the risk of anal sphincter injury. Material and Methods: Seventy three pregnant women who had their first vaginal delivery over 37 weeks of gestation between April 2019 and April 2020 were included in the study at Bezmialem Vakıf University Gynecology and Obstetrics Clinic.Women who underwent the Kristeller maneuver were recruited as cases. Obstetric and fetal parameters that could influence the onset of perineal tears were studied. All women underwent a transperineal 3/4D ultrasound within 48h after birth. Transperineal ultrasound results were compared between cases and controls. Multivariate logistic regression analysis was performed to identify independent risk factors for obstetric anal sphincter injuries (OASIS). Results: Total 73 women were included in the study. Fundal pressure was applied to 37 women. BMI of the patients were similar. When the demographic features of the fetus were examined, there was no statistically significant difference. The mean second phase duration of the group undergoing fundal pressure was 57.3 ± 19.2 and the control group was 37.3 ± 8.6 (p <0.0001). After physical examination in any patient 3./4. degree of perineal laceration was observed. However, after the transperineal ultrasound, "half moon" sign was observed in 1 patient in both groups. Mediolateral episiotomy was significantly higher in the kristeller group (p <0.0001). Conclusion: No significant anal sphincter damage was observed in the fundal pressure group. Mediolateral episiotomy and the second stage of delivery are significantly higher in the group of kristeller. The 3D transperineal ultrasound is helpful to determine the anal sphincter injury the immediate postpartum, with no discomfort for patients, as well as for establishing those early sphincter injuries that go unnoticed during vaginal delivery. Key words: fundal pressure, Kristeller maneuver, obstetric anal sphincter injuries, transperineal ultrasound