Pelvic floor dysfunction after intervention, compared with expectant management, in prolonged second stage of labour: A population‐based questionnaire and cohort study

Abstract Objective To investigate the effect of vacuum extraction (VE) or caesarean section (CS), compared with expectant management, on pelvic floor dysfunction (PFD) 1–2 years postpartum in primiparous women with a prolonged second stage of labour. Design A population‐based questionnaire and cohort study. Setting Stockholm, Sweden. Population A cohort of 1302 primiparous women with a second stage duration of ≥3 h, delivering from December 2017 to November 2018. Methods The 1‐year follow‐up questionnaire from the Swedish National Perineal Laceration Register was distributed 12–24 months postpartum. Exposure was VE or CS at 3–4 h or 4–5 h, compared with expectant management. Main outcome measures Pelvic floor dysfunction was defined as at least weekly symptoms of urinary incontinence, pelvic organ prolapse or a Wexner score of ≥4. The risk of PFD was calculated using Poisson regression with robust variance estimation, presented as crude and adjusted relative risks (RRs and aRRs) with 95% confidence intervals (95% CIs). The implication of obstetric anal sphincter injury (OASI) on pelvic floor disorders was investigated through mediation analysis. Results In total, 35.1% of women reported PFD. Compared with expectant management, the risk of PFD was increased after VE at 3–4 h (aRR 1.33, 95% CI 1.06–1.65) and 4–5 h (aRR 1.34, 95% CI 1.05–1.70), but remained unchanged after CS. The increased risk after VE was not mediated by OASI. Conclusions Pelvic floor dysfunction was common in primiparous women after a prolonged second stage, and the risk of PFD increased after VE but was unaffected by CS, compared with expectant management. If a spontaneous vaginal delivery eventually occurred, allowing an extended duration of labour did not increase the risk of PFD.