BACKGROUND: The exact positioning of the dominant hand at the time of manual perineal protection (MPP) is not clearly specified. The main aim of this work was to identify the place on the perineum where pressure needs to be applied to achieve optimal forward fetal head displacement away from the anal sphincters using the bregma to posterior fourchette distance (BFD) and the perineal body length (PBL). METHODS: This was a two-center prospective cohort study. Term cephalic singleton nulliparous women having spontaneous vaginal delivery were considered eligible for recruitment into the study. Once crowning was diagnosed and just prior the initiation of manual perineal protection (MPP) or cutting an episiotomy, the BFD and PBL were measured using a standardized measurement protocol. RESULTS AND DISCUSSION: A total of 100 women (50 women in each center) were recruited into the study. The overall mean BFD was 2.8 ± 0.5 cm. The overall mean PBL was 4.4 ± 0.8 cm. There were no statistically significant differences between the measurements taken in both units regarding BFD or PBL (p = 0.81 and 0.10 respectively). There was a weak correlation between both measurements. Based on our measured parameters, it seems that the most effective point to apply perineal pressure to displace the head away from the anus is approximately 1 - 1.5 cm anterior to the anal margin. CONCLUSION: Measurements generated by this study will form the bases of future biomechanical studies to confirm their validity.

• Keywords
• Manual perineal protection, Perineal body, Perineal mapping, Perineal tension,
• MeSH
• Anal Canal MeSH
• Adult MeSH
• Episiotomy MeSH
• Head * MeSH
• Humans MeSH
• Young Adult MeSH
• Version, Fetal * methods   MeSH
• Perineum * anatomy & histology   MeSH
• Prospective Studies MeSH
• Pregnancy MeSH
• Pressure MeSH
• Delivery, Obstetric * methods   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Young Adult MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH

INTRODUCTION AND HYPOTHESIS: Several studies have assessed birth-related deformations of the levator ani muscle (LAM) and perineum on models that depicted these elements in isolation. The main aim of this study was to develop a complex female pelvic floor computational model using the finite element method to evaluate points and timing of maximum stress at the LAM and perineum in relation to the birth process. METHODS: A three-dimensional computational model of the female pelvic floor was created and used to simulate vaginal birth based on data from previously described real-life MRI scans. We developed three models: model A (LAM without perineum); model B (perineum without LAM); model C (a combined model with both structures). RESULTS: The maximum stress in the LAM was achieved when the vertex was 9 cm below the ischial spines and measured 37.3 MPa in model A and 88.7 MPa in model C. The maximum stress in the perineum occurred at the time of distension by the suboocipito-frontal diameter and reached 86.7 MPa and 119.6 MPa in models B and C, respectively, while the stress in the posterior fourchette caused by the suboccipito-bregmatic diameter measured 36.9 MPa for model B and 39.8 MPa for model C. CONCLUSIONS: Including perineal structures in a computational birth model simulation affects the level of stress at the LAM. The maximum stress at the LAM and perineum seems to occur when the head is lower than previously anticipated.

• Keywords
• Birth, Delivery, Levator, Modeling, Muscle, Partum, Perineal, Stress, Tension,
• MeSH
• Finite Element Analysis MeSH
• Humans MeSH
• Pelvic Floor * diagnostic imaging   MeSH
• Perineum MeSH
• Pregnancy MeSH
• Delivery, Obstetric * MeSH
• Dental Porcelain MeSH
• Check Tag
• Humans MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• finesse MeSH Browser
• Dental Porcelain MeSH

INTRODUCTION AND HYPOTHESIS: Quantitative characterization of the birth canal and critical structures before delivery may provide risk assessment for maternal birth injury. The objective of this study was to explore imaging capability of an antepartum tactile imaging (ATI) probe. METHODS: Twenty randomly selected women older than 21 years with completed 35th week of pregnancy and a premise of vaginal delivery were enrolled in the feasibility study. The biomechanical data were acquired using the ATI probe with a double-curved surface, shaped according to the fetal skull and equipped with 168 tactile sensors and an electromagnetic motion tracking sensor. Software package COMSOL Multiphysics was used for finite element modeling. Subjects were asked for assessment of pain and comfort levels experienced during the ATI examination. RESULTS: All 20 nulliparous women were successfully examined with the ATI. Mean age was 27.8 ± 4.1 years, BMI 30.7 ± 5.8, and week of pregnancy 38.8 ± 1.4. Biomechanical mapping with the ATI allowed real-time observation of the probe location, applied load to the vaginal walls, and a 3D tactile image composition. The nonlinear finite element model describing the stress-strain relationship of the pelvic tissue was developed and used for calculation of Young's modulus (E). Average perineal elastic modulus was 11.1 ± 4.3 kPa, levator ani 4.8 ± 2.4 kPa, and symphysis-perineum distance was 30.1 ± 6.9 mm. The pain assessment level for the ATI examination was 2.1 ± 0.8 (scale 1-4); the comfort level was 2.05 ± 0.69 (scale 1-3). CONCLUSIONS: The antepartum examination with the ATI probe allowed measurement of the tissue elasticity and anatomical distances. The pain level was low and the comfort level was comparable with manual palpation.

• Keywords
• Biomechanics of parturition, Elastography, Finite element model, Perineal elasticity, Tactile imaging,
• MeSH
• Adult MeSH
• Elasticity Imaging Techniques * MeSH
• Humans MeSH
• Young Adult MeSH
• Pelvic Floor * diagnostic imaging   MeSH
• Perineum diagnostic imaging   MeSH
• Parturition MeSH
• Feasibility Studies MeSH
• Pregnancy MeSH
• Imaging, Three-Dimensional MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Young Adult MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

INTRODUCTION AND HYPOTHESIS: Objective of this study was to develop an MRI-based finite element model and simulate a childbirth considering the fetal head position in a persistent occiput posterior position. METHODS: The model involves the pelvis, fetal head and soft tissues including the levator ani and obturator muscles simulated by the hyperelastic nonlinear Ogden material model. The uniaxial test was measured using pig samples of the levator to determine the material constants. Vaginal deliveries considering two positions of the fetal head were simulated: persistent occiput posterior position and uncomplicated occiput anterior position. The von Mises stress distribution was analyzed. RESULTS: The material constants of the hyperelastic Ogden model were measured for the samples of pig levator ani. The mean values of Ogden parameters were calculated as: μ1 = 8.2 ± 8.9 GPa; μ2 = 21.6 ± 17.3 GPa; α1 = 0.1803 ± 0.1299; α2 = 15.112 ± 3.1704. The results show the significant increase of the von Mises stress in the levator muscle for the case of a persistent occiput posterior position. For the optimal head position, the maximum stress was found in the anteromedial levator portion at station +8 (mean: 44.53 MPa). For the persistent occiput posterior position, the maximum was detected in the distal posteromedial levator portion at station +6 (mean: 120.28 MPa). CONCLUSIONS: The fetal head position during vaginal delivery significantly affects the stress distribution in the levator muscle. Considering the persistent occiput posterior position, the stress increases evenly 3.6 times compared with the optimal head position.

• Keywords
• FEM modeling, Levator ani muscle trauma, Ogden material model, Persistent occiput posterior position, Vaginal delivery,
• MeSH
• Finite Element Analysis MeSH
• Labor Presentation * MeSH
• Pelvic Floor diagnostic imaging   MeSH
• Fetus * MeSH
• Swine MeSH
• Pregnancy MeSH
• Delivery, Obstetric MeSH
• Animals MeSH
• Check Tag
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: Manual perineal protection (MPP) is an intrapartum intervention suggested to protect perineal integrity during childbirth. Proper execution of MPP is complex and evaluation of its true contribution is difficult in the clinical setting because of the large number of obstetric variables, some of which are hardly quantifiable. In this study we aimed to gather initial data on the forces executed by the accoucheur's thumb, index and middle fingers during MPP at the time of fetal head expulsion, quantify the duration of the intervention and investigate the timely interaction of the different components of MPP. METHODS: Two bespoke right-handed measurement gloves (MG), with built in sensors, were designed and produced. The MG allowed the electronic real-time measurement of applied forces during MPP and transferred this data wirelessly to an integrated computer system. Sterile gloves were worn over the MG when used at the time of birth. The study was undertaken between January and December 2019. Singleton, term pregnant women having their first vaginal birth who provided a valid written consent were enrolled into this prospective pilot study. All deliveries were undertaken by one of two obstetricians experienced in MPP. RESULTS: Twenty women were enrolled. The mean duration of execution of MPP during the last contraction was 13.6 s. In 20% it lasted < 5 s. The overall mean values of the average and maximum forces of the thumb, index and middle fingers were 26.7 N; 25.5 N; 20.2 N and 34.3 N; 32.6 N; and 27.6 N respectively. The onset of fingers and thumb activity was simultaneous in 13 cases (65%), while in seven (35%) deliveries the middle finger's force activity was initiated later. CONCLUSIONS: MPP during fetal head expulsion happens over a short period of time. In the majority of cases the thumb and fingers actions started simultaneously. There were differences in the duration of application and the forces executed by the fingers and thumb between the two practitioners, however this was only significant for thumb measurements. The results obtained will aid in improving further MPP modeling studies to optimize the technique.

• Keywords
• Computational modelling, Duration, Finnish method, Forces, Keys: Manual perineal protection, Physiology, Pressure, Vaginal delivery, Variability,
• MeSH
• Benchmarking MeSH
• Adult MeSH
• Head MeSH
• Humans MeSH
• Perineum physiology   MeSH
• Pilot Projects MeSH
• Prospective Studies MeSH
• Fingers MeSH
• Pregnancy MeSH
• Delivery, Obstetric instrumentation   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

INTRODUCTION AND HYPOTHESIS: First 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. METHODS: This 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. RESULTS: Nine 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). CONCLUSION: Though 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.

• Keywords
• BMI, Forceps, Incontinence, Maternal age, Pelvic organ prolapse,
• MeSH
• Adult MeSH
• Fecal Incontinence etiology   MeSH
• Urinary Incontinence etiology   MeSH
• Humans MeSH
• Pelvic Floor Disorders etiology   MeSH
• Parity MeSH
• Parturition MeSH
• Prospective Studies MeSH
• Pregnancy MeSH
• Delivery, Obstetric adverse effects   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Observational Study MeSH

BACKGROUND: The objectives of this study were to explore the course of labor and the risk of obstetric anal sphincter injury at the first vaginal birth after cesarean section (fVBAC) in comparison to primiparous vaginal birth (PVB) in women without epidural analgesia and to assess if laboring before the previous cesarean affected these outcomes. METHODS: All fVBACs without epidural analgesia and the subsequent PVBs (controls) between 2012 and 2016 were included in this retrospective cohort study. Data were collected from health records and included maternal demographics, gestational age, and labor details (duration of 1st and 2nd stages, labor induction or augmentation, birthweight, operative vaginal birth, estimated blood loss, extent of childbirth trauma) in both groups as well as cervical dilation at the time of previous cesarean in the fVBAC group. Wilcoxon and Chi-square tests were used for data analyses. RESULTS: The study comprised 510 women; 255 fVBACs and 255 controls. The majority of fVBACs were after a pre-labor cesarean section - 177 (69.4%). There was a statistically significant difference in the recorded duration of first stage between the fVBACs and controls (289 vs. 347 min respectively, p < .001). Women were less likely to have an intact perineum in the fVBAC group (29.8 vs. 43.1%, p < 0.01), however, there was no statistically significant difference in anal sphincter injury rates between both groups (2.3 vs. 1.9%, p = 0.76). The groups differed in rates of cervical tears requiring suturing (21.2 vs. 12.9%, p = 0.01). On further subgroup analysis, the duration of first stage of labor was shorter in women who previously had a caesarean section late in labor (≥ 8 cm cervical dilatation) compared to a pre-labor cesarean section, however, there were no differences in other outcomes. CONCLUSION: Compared to primiparous women having a vaginal birth, women having their first vaginal birth after a cesarean section have a shorter 1st stage of labor (particularly if the cesarean was performed in advanced labor), a higher risk of sustaining cervical lacerations and perineal trauma. However, there was no difference in the risk of sustaining obstetric anal sphincter injuries between the study groups.

• Keywords
• Cervical laceration, Childbirth trauma, OASI, Perineal tear, Vaginal birth after cesarean,
• MeSH
• Anal Canal injuries   MeSH
• Time Factors MeSH
• Cervix Uteri injuries   MeSH
• Cesarean Section * MeSH
• Adult MeSH
• Lacerations etiology   MeSH
• Humans MeSH
• Young Adult MeSH
• Perineum injuries   MeSH
• Labor Stage, First * MeSH
• Retrospective Studies MeSH
• Pregnancy MeSH
• Vaginal Birth after Cesarean adverse effects   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Young Adult MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

OBJECTIVE: The aim of this study was to evaluate whether a previously identified modification of Viennese method of perineal protection remains most effective for reduction of perineal tension in cases with substantially smaller or larger fetal heads. METHODS: A previously designed finite element model was used to compare perineal tension of different modifications of the Viennese method of perineal protection to "hands-off" technique for three different sizes of the fetal head. Quantity and extent of tension throughout the perineal body during vaginal delivery at the time when the suboccipito-bregmatic circumference passes between the fourchette and the lower margin of the pubis was determined. RESULTS: The order of effectiveness of different modifications of manual perineal protection was similar for all three sizes of fetal head. The reduction of perineal tension was most significant in delivery simulations with larger heads. The final position of fingers 2cm anteriorly from the fourchette (y = +2) consistently remains most effective in reducing the tension. The extent of finger movement along the anterior-posterior (y-axis) contributes to the effectiveness of manual perineal protection. CONCLUSION: Appropriately performed Viennese manual perineal protection seems to reduce the perineal tension regardless of the fetal head size, and thus the method seems to be applicable to reduce risk of perineal trauma for all parturients.

• MeSH
• Finite Element Analysis MeSH
• Head anatomy & histology   MeSH
• Obstetric Labor Complications prevention & control   MeSH
• Humans MeSH
• Perineum injuries   MeSH
• Fetus anatomy & histology   MeSH
• Pregnancy MeSH
• Delivery, Obstetric adverse effects   methods   MeSH
• Check Tag
• Humans MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

INTRODUCTION AND HYPOTHESIS: Comparison of the modifications of the Viennese method of manual perineal protection (VMPP) and hands-off delivery techniques by applying basic principles of mechanics with assessments of tensions within perineal structures using a novel biomechanical model of the perineum. Evaluation of the role of the precise placements of the accoucheur's posterior (dominant) thumb and index finger in perineal tissue tension when performing a modified Viennese method of MPP. METHODS: We carried out an experimental study on a biomechanical model of the perineum at NTIS (New Technologies for Information Society, Pilsen, Czech Republic). Hands-off and 38 variations of VMPP were simulated during vaginal delivery with the finite element model imitating a clinical lithotomy position. RESULTS: The main outcome measures were quantity and extent of strain/tension throughout the perineal body during vaginal delivery. Stress distribution between modifications of VMPP showed a wide variation in peak perineal tension from 72 to 102 % compared with 100 % for the "hands-off" technique. Extent of reduction depended on the extent of finger movement across a horizontal, transverse x-axis, and on final finger position on a vertical, antero-posterior y-axis. The most effective modification of VMPP was initial position of fingers 12 cm apart (x = ±6) on the x-axis, 2 cm anteriorly from the posterior fourchette (y = +2) on the y-axis with 1cm movement of both finger and thumb toward the midline on the x-axis (Δx = 1) with no movement on the y-axis (Δy = 0). CONCLUSIONS: In a biomechanical assessment with simulation of vaginal delivery, exact placement of fingertips on the perineal skin, together with their co-ordinated movement, plays an important role in the extent of reduction of perineal tension.

• MeSH
• Models, Biological MeSH
• Biomechanical Phenomena MeSH
• Humans MeSH
• Perineum injuries   MeSH
• Computer Simulation MeSH
• Parturition MeSH
• Fingers * MeSH
• Wounds and Injuries prevention & control   MeSH
• Delivery, Obstetric methods   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH