<scp>OC</scp>09.05: Intrapartum predictors of pelvic floor trauma

Abstract

Damage to the pelvic floor during vaginal childbirth is common, and may take the form of levator avulsion or irreversible over-distension of the levator hiatus. Both are likely to be major risk factors for pelvic organ prolapse. In this study we identified intrapartum risk factors for such trauma. This is a retrospective observational study using data sets of primiparous women seen in two perinatal studies. Between 2005 and 2014; 1148 patients carrying an uncomplicated singleton pregnancy were seen for 4D pelvic floor ultrasound and an interview. Post-processing analysis for hiatal over-distension and avulsion was performed blinded against clinical data. Results were analyzed against obstetric data. Of 1148 women, 871 (76%) returned for a 3 month assessment. Of those, 18 were excluded due to incomplete ultrasound data, 6 due to missing delivery data, and 3 due to a second pregnancy, leaving 844 women for analysis. 609 women delivered vaginally: 452 (54%) had a normal vaginal delivery, 102 (12%) a vacuum, and 55 (6%) a forceps. 235 (28%) had a Caesarean section. On multivariate analysis forceps, length of second stage, episiotomy, birthweight and OASIS were identified as predictors of avulsion. There were no significant predictors of microtrauma (table 1). OC09.05: Table 1. Intrapartum predictors of pelvic floor trauma (n = 609) Forceps, a prolonged second stage, episiotomy, birthweight and a third or fourth degree perineal tear were predictive for levator avulsion. Irreversible overdistension or 'microtrauma' had no associated intrapartum predictors.