Introduction and hypothesisFirst vaginal delivery severely interferes with pelvic floor anatomy and function. This study determines maternal and pregnancy-related risk factors for pelvic floor dysfunction (PFD), including urinary incontinence (UI), urgency, anal incontinence (AI), pelvic organ prolapse (POP) and levator ani muscle (LAM) avulsion.MethodsThis is a single-centre prospective observational cohort study on healthy women in their first singleton pregnancy. All underwent clinical and 3D transperineal ultrasound examination at 6 weeks and 12 months postpartum. Objective outcomes were POP-Q and presence or absence of LAM trauma. Functional outcomes were measured by the ICIQ-SF and PISQ 12. Multivariate regression was performed to determine birth and maternal habitus-related risk factors for UI, urgency, AI, dyspareunia, LAM avulsion and ballooning.ResultsNine hundred eighty-seven women were included. Risk factors for UI were maternal age per year of age (OR: 1.09; 95% CI: 1.04–1.13; p = 0.0001) and BMI before pregnancy (OR: 1.08; 95% CI: 1.04–1.13; p = 0.001); for POP stage II+ maternal age (OR: 1.08; 95% CI: 1.08–1.14; p = 0.005). Avulsion was more likely after forceps (OR: 3.22; 95% CI:1.54–8.22; p = 0.015) but less likely after epidural analgesia (OR: 0.58; 95% CI: 0.37–0.90; p = 0.015) and grade I perineal rupture (OR: 0.50; 95% CI: 0.29–0.85; p = 0.012). Ballooning was more likely at increased maternal age (OR: 1.08; 95% CI: 1.02–1.13; p = 0.005), epidural (OR: 1.64; 95% CI: 1.06–2.55; p = 0.027) and grade I perineal rupture (OR: 1.79; 95% CI: 1.10–2.90; p = 0.018).ConclusionThough maternal characteristics at birth such as age or BMI increase the risk of PFD, labour and birth factors play a similarly important role. The most critical risk factor for MLA avulsion was forceps delivery, while an epidural had a protective effect.Electronic supplementary materialThe online version of this article (10.1007/s00192-019-04044-2) contains supplementary material, which is available to authorized users.

Introduction and hypothesisDuring vaginal delivery, the levator ani muscle (LAM) undergoes severe deformation. This stress can lead to stretch-related LAM injuries. The objective of this study was to develop a sophisticated MRI-based model to simulate changes in the LAM during vaginal delivery.MethodsA 3D finite element model of the female pelvic floor and fetal head was developed. The model geometry was based on MRI data from a nulliparous woman and 1-day-old neonate. Material parameters were estimated using uniaxial test data from the literature and by least-square minimization method. The boundary conditions reflected all anatomical constraints and supports. A simulation of vaginal delivery with regard to the cardinal movements of labor was then performed.ResultsThe mean stress values in the iliococcygeus portion of the LAM during fetal head extension were 4.91–7.93 MPa. The highest stress values were induced in the pubovisceral and puborectal LAM portions (mean 27.46 MPa) at the outset of fetal head extension. The last LAM subdivision engaged in the changes in stress was the posteromedial section of the puborectal muscle. The mean stress values were 16.89 MPa at the end of fetal head extension. The LAM was elongated by nearly 2.5 times from its initial resting position.ConclusionsThe cardinal movements of labor significantly affect the subsequent heterogeneous stress distribution in the LAM. The absolute stress values were highest in portions of the muscle that arise from the pubic bone. These areas are at the highest risk for muscle injuries with long-term complications.

The groups showed comparable objective and subjective cure rates.

Objective and subjective cure rates following TVT-S are inferior to other tape procedures.