Objective To establish the incidence of levator ani muscle (LAM) avulsion in primiparous women and to develop a clinically applicable risk prediction model.Design Observational longitudinal cohort study.Setting District General University Hospital, United Kingdom.Sample Nulliparous women at 36 weeks of gestation and 3 months postpartum.Methods Four-dimensional transperineal ultrasound was performed during both visits. Tomographic ultrasound imaging at maximum contraction was used to diagnose no, minor or major LAM avulsion. A risk model was developed using multivariable ordinal logistic regression.Main outcome measures Incidence of LAM avulsion and its risk factors.Results Of 269 women with no antenatal LAM avulsion 71% (n = 191) returned postpartum. No LAM avulsion was found after caesarean section (n = 48). Following vaginal delivery the overall incidence of LAM avulsion was 21.0% (n = 30, 95% confidence interval [95% CI] 15.1-28.4). Minor and major LAM avulsion were diagnosed in 4.9% (n = 7, 95% CI 2.2-9.9) and 16.1% (n = 23, 95% CI 10.9-23.0), respectively. Risk factors were obstetric anal sphincter injuries (odds ratio [OR] 4.4, 95% CI 1.6-12.1), prolonged active second stage of labour per hour (OR 2.2, 95% CI 1.4-3.3) and forceps delivery (OR 6.6, 95% CI 2.5-17.2). A risk model and nomogram were developed to estimate a woman's individual risk: three risk factors combined revealed a 75% chance of LAM avulsion.Conclusions Twenty-one percent of women sustain LAM avulsion during their first vaginal delivery. Our risk model and nomogram are novel tools to estimate individual chances of LAM avulsion. We can now target postnatal women at risk of sustaining a LAM avulsion.Keywords Childbirth, incidence, levator ani avulsion, pelvic organ prolapse, risk prediction model, transperineal ultrasound.Please cite this paper as: van Delft K, Thakar R, Sultan AH, Schwertner-Tiepelmann N, Kluivers K. Levator ani muscle avulsion during childbirth: a risk prediction model.

Levator ani muscle (LAM) injuries occur in 13-

Objective To establish the relationship between postpartum levator ani muscle (LAM) avulsion and signs and/or symptoms of pelvic floor dysfunction (PFD).Design Observational longitudinal cohort study.Setting District General University Hospital, UK.Population or sample Primigravida at 36 weeks' gestation and 3 months postpartum.Methods Pelvic floor muscle strength (PFMS) and pelvic organ prolapse were assessed clinically using validated methods. Transperineal ultrasound was performed to identify LAM avulsion and measure hiatus dimensions. Validated questionnaires evaluated sexual function, urinary and faecal incontinence.Main outcome measures PFD signs and symptoms related to LAM avulsion.Results Two hundred and sixty nine primigravida without LAM avulsion participated and 71% (n = 191) returned postpartum. LAM avulsion was found in 21% of vaginal deliveries (n = 30, 95%CI 15.1-28.4%). Women with minor and major avulsion had worse PFMS (P < 0.038) and more anterior compartment prolapse (maximum stage 2; P < 0.024). Antenatal hiatus antero-posterior diameter on ultrasound was significantly smaller in women sustaining avulsion (P = 0.011). Postnatal measurements were significantly increased following avulsion. Women with major avulsion were less sexually active at both antenatal and postnatal periods (P < 0.030). These women had more postnatal urinary incontinence and symptoms such as reduced vaginal sensation and 'too loose vagina'. No postnatal differences were found for faecal incontinence, prolapse symptoms or quality of life. The correlation of differences in variables was only slight-fair with avulsion severity.Conclusions Twenty one percent of women sustain LAM avulsion during their first vaginal delivery with significant impact on signs and symptoms of PFD. As avulsion has been described as the missing link in the development of prolapse; longer term follow-up is vital.Keywords Childbirth, incontinence, levator ani avulsion, pelvic floor dysfunction, pelvic organ prolapse, transperineal ultrasound.Please cite this paper as: van Delft K, Sultan AH, Thakar R, Schwertner-Tiepelmann N, Kluivers K. The relationship between postpartum levator ani muscle avulsion and signs and symptoms of pelvic floor dysfunction.

Pelvic floor sonography is currently the gold standard in gynecology for the morphological diagnosis of incontinence and of functional disorders of the pelvic floor. X-ray examinations and MRI of the pelvic floor are much less common nowadays, and these examinations are usually only done to investigate more complex issues which cannot be adequately evaluated with ultrasonography. Diagnostic ultrasonography should be done both perioperatively and after surgery for urinary incontinence or prolapse to evaluate complications. Sonography also provides useful biofeedback and can be used to assess the patientʼs progress after conservative treatment. A review of recent international literature shows that, in the majority of studies, morphological diagnoses are obtained with sonography. A number of different methods are used for investigation and evaluation, which can make it difficult to compare the findings of different studies. While in previous years introital sonography and perineal ultrasound were the preferred 2D imaging methods used for diagnosis, more recent studies have focused on the use of 3D imaging methods. The basic principle, which applies to both approaches, is that metric assessments are secondary to descriptive evaluations as an important constituent of urogynecological diagnostics. Both methods are useful, particularly to assess complications after surgery for urinary incontinence and prolapse procedures, and both procedures have an important role to play in understanding and managing complications. Investigation TechniquesStandard diagnostics should include 2D imaging. The choice of where to insert the probe and whether to use 2D or 3D imaging depends on the availability of ultrasound units and probes. In principle, three different methods can be used for ultrasound investigation: 1. endosonographic applications: vaginal ultrasound, endo-anal sonography, 2. external applications: perineal/introital/abdominal ultrasound, 3. a combination of the two methods, as described by J. Kociszewski (Hagen) who refers to this approach as "pelvic floor sonography".Interdisciplinary S2k Guideline: Sonography in Urogynecology Short Version -AWMF Registry Number: 015/055Interdisziplinäre S2k-Leitlinie: Sonografie im Rahmen der urogynäkologischen DiagnostikKurzfassung -AWMF-Register-Nummer: 015/055

Objectives The modified Oxford scale (MOS)