Analysis of the obstetrician's posture and movements during a simulated forceps delivery.

BACKGROUND: The objective of this study was to identify and qualify, by means of a three-dimensional kinematic analysis, the postures and movements of obstetricians during a simulated forceps birth, and then to study the association of the obstetricians' experience with the technique adopted. METHOD: Fifty-seven volunteer obstetricians, 20 from the Limoges and 37 from the Poitiers University hospitals, were included in this multi-centric study. They were classified into 3 groups: beginners, intermediates, and experts, beginners having performed fewer than 10 forceps deliveries in real conditions, intermediates between 10 and 100, and experts more than 100. The posture and movements of the obstetricians were recorded between December 2020 and March 2021 using an optoelectronic motion capture system during simulated forceps births. Joint angles qualifying these postures and movements were analysed between the three phases of the foetal traction. These phases were defined by the passage of a virtual point associated with the forceps blade through two anatomical planes: the mid-pelvis and the pelvic outlet. Then, a consolidated ascending hierarchical classification (AHC) was applied to these data in order to objectify the existence of groups of similar behaviours. RESULTS: The AHC distinguished four different postures adopted when crossing the first plane and three different traction techniques. 48% of the beginners adopted one of the two raised posture, 22% being raised without trunk flexion and 26% raised with trunk flexion. Conversely, 58% of the experts positioned themselves in a "chevalier servant" posture (going down on one knee) and 25% in a "squatting" posture before initiating traction. The results also show that the joint movement amplitude tends to reduce with the level of expertise. CONCLUSION: Forceps delivery was performed in different ways, with the experienced obstetricians favouring postures that enabled observation at the level of the maternal perineum and techniques reducing movement amplitude. The first perspective of this work is to relate these different techniques to the traction force generated. The results of these studies have the potential to contribute to the training of obstetricians in forceps delivery, and to improve the safety of women and newborns.

Episiotomy practice in France and prevention of high-grade perineal tears at the time of operative vaginal delivery: a prospective multicentre ancillary cohort study.

INTRODUCTION AND HYPOTHESIS: Evidence suggests that episiotomies reduce the risk for obstetric anal sphincter injuries (OASIs) in operative vaginal deliveries (OVDs). However, there is limited evidence on the importance of episiotomy technique in this context. The primary objective of this study was to assess if an episiotomy suture angle >45° from the median line would be associated with a lower risk for OASIs at the time of OVD. METHODS: This was an ancillary study from the multicentre prospective cohort INSTRUMODA study. Of the 2,620 patients who had an OVD with a concomitant episiotomy between April 2021 and March 2022, a total of 219 fulfilled the inclusion criteria. Post-suturing photographs were used to assess episiotomy characteristics. RESULTS: Based on suture angles of ≤45° and >45° the study cohort was categorized into groups A (n = 155) and B (n = 64) respectively. The groups had comparable demographic and birth-related characteristics. The mean episiotomy length was significantly longer in group A than in group B (3.21 cm vs 2.84 cm; p = 0.009). Senior obstetricians performed more acute angled episiotomies than junior residents (p = 0.016). The total prevalence of OASIS was 2.3%, with no significant difference in rate of OASI between the two study groups. Birthweight was significantly higher in OASI births (p = 0.018) and spatula-assisted births were associated with higher risk for OASIs than ventouse or forceps (p = 0.0039). CONCLUSIONS: This study did not demonstrate a significant reduction in risk for OASI at the time of OVD when the episiotomy suture angle was >45° from the median line. However, these results should be interpreted with caution owing to the low prevalence of OASIs in our cohort.

A new approach to assessing the obstetrician's posture and movement during an instrumental forceps delivery.

INTRODUCTION: The number of deliveries by forceps decreases significantly in favour of the vacuum. Now, when the use of forceps is necessary, physicians less experimented with this procedure are likely to induce serious and preventable perineal or foetal injuries. Training therefore becomes essential. However, there are no clear recommendations on the technique to perform a delivery by forceps, namely the body posture and gesture to adopt. Our goal is then to provide a protocol that can help to determine if there is an optimal technique to perform a delivery by forceps. METHOD: We will include voluntary participants whose level of experience and type of practice differ. We will propose to record their postures and gestures using an optoelectronic motion analysis system during a forceps delivery simulated on a mannequin. We will also measure the traction force produced by the subject on the forceps using force platforms and technical markers placed on the forceps. We will then perform a principal component analysis to look for similar motion patterns. EXPECTED RESULTS: We plan to analyse about fifty participants (25 seniors and 25 juniors). Our hypothesis is that the realism of the simulation will be deemed satisfactory by the participants, that the experimental conditions will not modify their gestures, and that the degree of experience will result in different techniques. CONCLUSION: A better knowledge on the posture and gesture to adopt to realise a forceps delivery should improve the safety of women and new-borns. The results of this study could also be a valuable contribution for the training of obstetricians.

In vivo measurement of the elastic properties of pelvic floor muscles in pregnancy using shear wave elastography.

OBJECTIVE: We aimed to investigate changes in the elastic properties of levator ani muscle (LAM) and external anal sphincter (EAS) during pregnancy using shear wave elastography (SWE). Our secondary objective was to examine the association between the elastic properties of pelvic floor muscles (PFM) and perineal tears at childbirth. METHODS: This was a prospective monocentric study, including nulliparous women. Three visits were planned (14-18, 24-28, and 34-38 weeks) with a SWE assessment of the LAM and EAS at rest and during Valsalva maneuver. Then, we collected data about the delivery's characteristics. Assessments were performed using an Aixplorer V12® device (SL 18-5 linear probe) using a transperineal approach, reporting the shear modulus in kPa. We looked for changes in PFM's elastic properties during pregnancy using one-way ANOVA for repeated measures. We compared the mean shear modulus in late pregnancy for each muscle and condition between women with an intact perineum at delivery and those with a perineal tear using Student's t test. RESULTS: Forty-seven women were considered. Forty-five women had vaginal delivery of which 38 (84.4%) had perineal tears. We did not report any significant changes in the elastic properties of PFM during pregnancy. Women with an intact perineum at delivery had a stiffer EAS at Valsalva maneuver in late pregnancy (27.0 kPa vs. 18.2 kPa; p < 0.005). CONCLUSIONS: There were no significant changes in the elastic properties of the PFM in pregnancy. Stiffer EAS in late pregnancy appears to be associated with a lower incidence of perineal tears.

Oxytocin versus prostaglandins for labour Induction of women with an unfavourable cervix after 24 hours of cervical ripening (OPIC): protocol for an open multicentre randomised non-inferiority trial.

INTRODUCTION: It remains uncertain whether the most appropriate management for women with an unfavourable cervix after 24 hours of cervical ripening is repeating the ripening procedure or proceeding directly to induction by oxytocin. No adequately powered trial has compared these strategies. We hypothesise that induction of labour with oxytocin among women who have just undergone an ineffective first ripening procedure is not associated with a higher risk of caesarean delivery than a repeated cervical ripening with prostaglandins. METHODS AND ANALYSIS: We will conduct a multicentre, non-inferiority, open-label, randomised controlled trial aimed at comparing labour induction by oxytocin with a second cervical ripening that uses prostaglandins (slow-release vaginal dinoprostone; oral misoprostol 25 µg; dinoprostone vaginal gel 2 mg). Women (n=1494) randomised in a 1:1 ratio in 10 French maternity units must be ≥18 years with a singleton fetus in vertex presentation, at a term from ≥37+0 weeks of gestation, and have just completed a 24-hour cervical ripening procedure by any method (pharmacological or mechanical) with a Bishop score ≤6. Exclusion criteria comprise being in labour, having more than 3 contractions per 10 min, or a prior caesarean delivery or a history of uterine surgery, or a fetus with antenatally suspected severe congenital abnormalities or a non-reassuring fetal heart rate. The primary endpoint will be the caesarean delivery rate, regardless of indication. Secondary outcomes concern delivery, perinatal morbidity, maternal satisfaction and health economic evaluations. The nature of the assessed procedures prevents masking the study investigators and patients to group assignment. ETHICS AND DISSEMINATION: All participants will provide written informed consent. The ethics committee 'Comité de Protection des Personnes Ile de France VII' approved this study on 2 April 2021 (No 2021-000989-15). Study findings will be submitted for publication and presented at relevant conferences. TRIAL REGISTRATION NUMBER: NCT04949633.

In vivo assessment of the elastic properties of the external anal sphincter in term pregnant women using shear wave elastography.

INTRODUCTION AND HYPOTHESIS: The objective was to assess the intraobserver intersession and interobserver intrasession reliability of shear wave elastography applied to the external anal sphincter in term pregnant women. METHODS: This prospective study involved nulliparous pregnant women at 37 weeks or more with two visits (V1: one observer; V2 two observers) planned within a 12-h to 7-day interval. Measurements were performed using an Aixplorer V12® device with an SL 18-5 linear probe using a transperineal approach, allowing a measurement of the shear modulus (SM) in kPa. Measures were performed at rest, Valsalva maneuver, and maximal contraction. Reliability was assessed using the intraclass correlation coefficient (ICC). The study was approved by an ethics committee (ID RCB: 2020-A00764-65). RESULTS: A total of 37 women were included. Intraobserver reliability was excellent at rest (ICC = 0.91 [0.84-0.95) and good during the Valsalva maneuver (ICC = 0.83 [0.72-0.90]) and contraction (ICC = 0.85 [0.75-0.91]). Interobserver reliability was good at rest (ICC = 0.79 [0.66-0.87]) and during Valsalva (ICC = 0.84 [0.73-0.90]), but moderate during contraction (ICC = 0.70 [0.53-0.82]). CONCLUSIONS: Shear wave elastography is a reliable tool for assessing the elastic properties of the external anal sphincter in term pregnant women.

Impact of fetal manipulation on maternal and neonatal severe morbidity during shoulder dystocia management.

PURPOSE: There are few data on maternal and neonatal morbidities associated with shoulder dystocia (SD), depending on the use of fetal manipulation (FM). A prior 5-year study was conducted in our center in 2012 for this purpose. Our objective was to compare severe maternal and neonatal morbidities according to FM execution in a larger cohort. METHODS: We conducted a retrospective study between 2007 and 2020. SD was considered when additional maneuvers were required to complete a delivery. Severe maternal morbidity was defined as the occurrence of obstetric anal sphincter injury (OASI). Severe neonatal morbidity was defined as Apgar < 7 at 5 min and/or cord arterial pH < 7.1 and/or or a permanent brachial plexus palsy. We studied these data in the FM group compared to the non- FM group. RESULTS: FM was associated with increased OASI rates (21.1% vs. 3.8%, OR = 6.72 [2.7-15.8]). We found no significant difference in severe neonatal morbidity. Maternal age > 35 and FM appear to be associated with the occurrence of OASI, with ORa = 13.3 [1.5-121.8] and ORa = 5.3 [2.2-12.8], respectively. FM was the only factor associated with the occurrence of severe neonatal morbidity (ORa = 2.3 [1.1-4.8]. The rate of episiotomy was significantly decreased (20% versus 5% p < 0.05) and there was an increase in the rate of SD managed with FM in our center. CONCLUSION: FM is the only factor associated with an increased risk of OASI. In case of failure of non-FM maneuvers, the rapid implementation of FM maneuvers resulted in no difference regarding severe neonatal morbidity.

French guidelines for restrictive episiotomy during instrumental delivery were not followed by an increase in obstetric anal sphincter injury.

The objective was to assess the influence of the French guidelines in favor of a restrictive use of episiotomy on both episiotomy and obstetric anal sphincter injury (OASI) rates during instrumental delivery. It was aulticenter study involving 193 maternities between 2000 and 2016. We included women with a singleton pregnancy, with cephalic presentation at 34 weeks of gestation or more who underwent an instrumental delivery. The study period was divided into three phases: 2000-2005 (reference) 2006-2011, and 2012-2016. We calculated the adjusted relative risk (aRR) of episiotomy and OASI and investigated for changes in episiotomy and OASI rates over time by using Prais-Winsten regression. We considered 96,035 deliveries. The episiotomy's risk was lower in 2006-2011 (69.4%) and 2012-2016 (59.1%) compared to 2000-2005 (81.2%), respectively: aRR 0.93 [0.92-0.95] and 0.89 [0.87-0.90]. The OASI's risk was higher in 2006-2011 (2.5%) and 2012-2016 (3.1%) compared to 2000-2005, respectively: aRR 1.30 [1.10-1.53]) and 1.57 [1.33-1.85]. However, Prais-Winsten regression showed no difference in the OASI rate during the study period. We observed a massive decrease in episiotomy use and a moderate increase in crude OASI's rate but multivariate analysis failed to report an association between these outcomes.

Cephalic marks and well-being in newborns after operative vaginal delivery.

OBJECTIVES: To compare the incidence of cephalic marks in newborns exposed to operative vaginal delivery and those who are not. We examined the factors associated with alterations in neonatal well-being and with cephalic mark occurrence. METHODS: Prospective study involving singleton term newborns delivered in a cephalic presentation. Newborns in the operative group were matched with newborns born on the same day without instruments required. A cephalic mark was defined as any mark or edema on the newborn's skin between 12 and 72 hours of life. Neonatal well-being was assessed by analgesic consumption, neonatal discomfort (EDIN score of 1 or more), and prolonged hospitalization (4 days or more). We compared the operative and spontaneous groups and determined the relative risk (RR) for cephalic marks. We investigated the factors associated with alterations in neonatal well-being and factors associated with cephalic mark occurrence in the case of operative delivery using multivariate logistic regression analysis. RESULTS: A total of 135 newborns were included in each group. The incidence of cephalic marks was higher in the operative group (RR = 13.3 [6.0-29.5]). In case of operative delivery, cephalic marks were associated with neonatal discomfort (adjusted odds ratios [aOR] = 8.2 [2.2-30.6]) and analgesic consumption (aOR = 3.0 [1.2-7.1]). The number of cephalic marks was higher in cases with sequential use of vacuum and forceps (aOR = 3.5 [1.1-11.7]) and forceps only deliveries (aOR = 3.0 [1.1-8.1]) relative to vacuum only deliveries. CONCLUSIONS: Operative delivery increases the risk of neonatal cephalic marks, which can negatively affect neonatal well-being.

A New Paradigm in Managing Advanced Ovarian Cancer: Differentiating Patients Requiring Neoadjuvant Treatment from Primary Cytoreduction.

Our study aims to evaluate the comparability of primary debulking surgery (PDS) and neoadjuvant chemotherapy (NACT) patients. This single-center retrospective study includes all patients treated for advanced stages high-grade serous ovarian carcinomas (HGSOC) between 2007 and 2017. Preoperative characteristics and postoperative outcomes were compared after a propensity score matching analysis. Of the 221 patients included, 38% underwent PDS, and 62% received NACT. There was no age difference at diagnosis; however, CA125 levels, PCI score levels, and rates of stage IV were higher in the NACT group. There were no differences concerning the rate and the severity of complications (p = 0.29). The propensity score distribution showed a broad distinction between PDS patients and NACT patients with no significant overlap. Survival analyses demonstrate, after a median follow-up of 66.5 months, an overall survival (OS) of 105.9 and progression-free survival (PFS) of 29.2 months in the PDS group, compared to OS of 52.8 and PFS of 18.9 months in the NACT group. Advanced HGSOC is a heterogeneous population, in which inoperable patients should be differentiated from PDS patients based on many factors, primarily tumor burden.

Transperineal ultrasound shear-wave elastography is a reliable tool for assessment of the elastic properties of the levator ani muscle in women.

Our main objective was to assess the intraoperator intersession reproducibility of transperineal ultrasound Shear Wave Elastography (SWE) to measure the levator ani muscle (LAM) elastic properties. Secondary objective was to compare reproducibility when considering the mean of three consecutives measurements versus one. In this prospective study involving non-pregnant nulliparous women, two visits were planned, with a measurement of the shear modulus (SM) on the right LAM at rest, during Valsalva maneuver and maximal contraction. Assessments were done with a transperineal approach, using an AIXPLORER device with a linear SL 18-5 (5-18 MHz) probe. For each condition, 3 consecutive measures were performed at each visit. The mean of the three measures, then the first one, were considered for the reproducibility by calculating intraclass correlation coefficient (ICC), and coefficient of variation (CV). Twenty women were included. Reproducibility was excellent when considering the mean of the 3 measures at rest (ICC = 0.90; CV = 15.7%) and Valsalva maneuver (ICC = 0.94; CV = 10.6%), or the first of the three measures at rest (ICC = 0.87; CV = 18.6%) and Valsalva maneuver (ICC = 0.84; CV = 19.9%). Reproducibility was fair for measurement during contraction. Transperineal ultrasound SWE is a reliable tool to investigate LAM elastic properties at rest and during Valsalva maneuver.

How can we improve our practices in obstetric anal sphincter injury prevention, diagnosis, and management of symptomatic women?

Obstetric anal sphincter injury (OASI) is strongly associated with a major negative impact on women's health. Due to the consequences of an undiagnosed and therefore unrepaired OASI, it is essential to prevent or at least diagnose OASI at childbirth. We need to promote training of professionals to improve OASI screening at childbirth. High-risk situations such as operative delivery must be identified and preventive strategies such as the choice of a less traumatic instrument (vacuum) and mediolateral episiotomy should be considered. For a woman with OASI and/or symptoms, postnatal consultation with a specialist on pelvic floor disorders is essential to correctly orient her toward an adequate care pathway and to eventually identify occult or underestimated OASI. More data are required on therapeutic approaches for symptomatic women, primarily including physical therapy, sacral neuromodulation, delayed sphincter repair and palliative devices.

A core outcome set development for a French national prospective study about the effect of mediolateral episiotomy on obstetric anal sphincter injury during operative vaginal delivery (INSTRUMODA).

BACKGROUND: We aimed at developing a core outcome and variables of interest set to investigate the effects of mediolateral episiotomy on Obstetric Anal Sphincter Injury (OASI) during and after operative delivery in nulliparous women in a large-scale one-year observational French study including 15,000 women (INSTRUMODA). METHODS: A list of outcomes and variables of interest was suggested to obstetricians participating in the INSTRUMODA study using online questionnaires divided into 7 categories: the woman's history and course of pregnancy, course of labor, modalities of operative delivery, episiotomy characteristics, immediate maternal morbidity, one-year maternal morbidity, immediate neonatal morbidity. We used a three-round DELPHI method to reach a consensus. In the first round, outcomes and variables considered as essential by 70% or more of obstetricians were included in the corpus whereas they were excluded when 70% rated them as "not important". In the second round, non-consensual outcomes and variables were reassessed and excluded or definitively included if considered as "not important" or essential by 50% or more of the obstetricians. During the first round, obstetricians were invited to suggest new outcomes and/or variables that were then assessed in the second and third round. We used the same method to develop a core outcome and variables of interest set in a population of women in the community recruited via an association of patients. At the end of the procedure the core outcome and variables of interest sets were merged to provide the final core outcome set for the INSTRUMODA study. RESULTS: Fifty-three obstetricians and 16 women filled out questionnaires. After the 3 rounds of Delphi procedure in each population, 74 outcomes and variables were consensually reported by obstetricians and 92 by women in the community. By mixing these two consensual corpora we reported a final consensual list of 114 variables of interest and outcomes for both obstetricians and women. CONCLUSION: We established a core outcome and variables of interest set among obstetricians and women in the community to investigate the association between mediolateral episiotomy and OASI during operative delivery. TRIAL REGISTRATION: The INSTRUMODA study was registered on https://clinicaltrials.gov on June 25, 2020 ( NCT04446780 ).

Does the McRoberts' manoeuvre need to start with thigh abduction? An innovative biomechanical study.

BACKGROUND: Guidelines and description about the achievement of the McRoberts manoeuvre are discordant, particularly concerning the need for abduction before the beginning of the manoeuvre. We sought to compare the biomechanical efficiency of the McRoberts' manoeuvre, with and without thigh abduction. METHODS: In a postural comparative study, twenty-three gravidas > 32 weeks of gestational age and not in labour were assessed during three repetitions of two McRoberts' manoeuvre that differed in terms of starting position. For the (i) McRoberts, the legs were initially placed in stirrups; for the (m) McRoberts, the legs were resting on the bed, with thighs in wide abduction. For each manoeuvre, flexion of the plane of the external conjugate of the pelvis on the spine (ANGce), hip flexion and abduction, were assessed using an optoelectronic motion capture system. Lumbar curve were assessed with Epionics Spine® system. Temporal parameters including movement duration or acceleration of the external conjugate were also computed. All values ​​obtained for the two types of manoeuvres were compared using a Wilcoxon matched-pairs signed-ranks test. The significance level was defined as p < 0.05. RESULTS: The starting position of McRoberts' otherwise had no effect on the maximum ANGce (p = 0.199), the minimal lordosis of the lumbar curve (p = 0.474), or the maximal hip flexion (p = 0.057). The other parameters were not statistically different according to the starting position (p > 0.005). CONCLUSION: Regardless of the starting position, the McRoberts' manoeuvre allows ascension of the pubic symphysis and reduction of the lumbar lordosis. This results imply that the McRoberts' manoeuvre could be performed with the legs initially placed in the stirrups.

In vivo assessment of the elastic properties of women's pelvic floor during pregnancy using shear wave elastography: design and protocol of the ELASTOPELV study.

BACKGROUND: Animal studies have reported an increase in pelvic floor muscle stiffness during pregnancy, which might be a protective process against perineal trauma at delivery. Our main objective is to describe the changes in the elastic properties of the pelvic floor muscles (levator ani, external anal sphincter) during human pregnancy using shear wave elastography (SWE) technology. Secondary objectives are as follows: i) to look for specific changes of the pelvic floor muscles compared to peripheral muscles; ii) to determine whether an association between the elastic properties of the levator ani and perineal clinical and B-mode ultrasound measures exists; and iii) to provide explorative data about an association between pelvic floor muscle characteristics and the risk of perineal tears. METHODS: Our prospective monocentric study will involve three visits (14-18, 24-28, and 34-38 weeks of pregnancy) and include nulliparous women older than 18 years, with a normal pregnancy and a body mass index (BMI) lower than 35 kg.m- 2. Each visit will consist of a clinical pelvic floor assessment (using the Pelvic Organ Prolapse Quantification system), an ultrasound perineal measure of the anteroposterior hiatal diameter and SWE assessment of the levator ani and the external anal sphincter muscles (at rest, during the Valsalva maneuver and during pelvic floor contraction), and SWE assessment of both the biceps brachii and the gastrocnemius medialis (at rest, extension and contraction). We will collect data about the mode of delivery and the occurrence of perineal tears. We will investigate changes in continuous variables collected using the Friedman test. We will look for an association between the elastic properties of the levator ani muscle and clinical / ultrasound measures using a Spearman test at each trimester. We will investigate the association between the elastic properties of the pelvic floor muscles and perineal tear occurrence using a multivariate analysis with logistic regression. DISCUSSION: This study will provide original in vivo human data about the biomechanical changes of pregnant women's pelvic floor. The results may lead to an individualized risk assessment of perineal trauma at childbirth. TRIAL REGISTRATION: This study was registered on https://clinicaltrials.gov on July 26, 2018 (NCT03602196).

Perineal suture practices. Are they up to date with the evidence based medicine data: A local experience into a university maternity?

OBJECTIVES: To investigate the prevalence of perineal suture techniques then to identify the factors influencing suturing technique choices. METHODS: Prospective, observational, monocentric study over 20 weeks in a university hospital. A personal questionnaire was completed by medical practitioners performing perineal sutures: years of experience, training attendance, suturing techniques usually used for degrees 1 and 2 tears/episiotomies. For each delivery with perineal tear/episiotomy, the professional answered on the type of suture performed and the reasons for choosing this technique. We distinguished discontinuous sutures (several stitches/continuous locking stitch) from continuous sutures (single thread, single continuous locking stitch). We evaluated the prevalence of the techniques used in our center as well as the factors associated with the choice of technique, then we described the characteristics of the professionals who responded to the survey and their suturing habits. RESULTS: Among the 401 perineal sutures, 45.4% of them were continuous (n = 182), discontinuous sutures were more performed. Discontinuous sutures were more common in 1st and 2nd degree tears. Residents/obstetricians performed significantly more continuous sutures than midwives. Whatever the type of suture technique used (continuous or discontinuous), professionals sutured in the way they felt most suitable to the degree of tearing/episiotomy. Fifty-one percent of midwives are trained in continuous technique, compared with 81% of residents/obstetricians. Midwives required training in 70% of cases and 64% of residents. CONCLUSIONS: It appears necessary to disseminate continuous suture techniques and to promote their training in order to improve our practices.

Tissue biomechanical behavior should be considered in the risk assessment of perineal trauma at childbirth.

Perineal trauma at childbirth is associated with strong negative impacts on a woman's health but remains unpredictable. Pregnancy induces several changes in biomechanical behavior in humans as in animals, namely, an increase in ligamentous laxity and an increase in vaginal distensibility. Pelvic floor muscles in rats are reported to exhibit specific behaviors during pregnancy. Increases in both stiffness and the number of sarcomeres in series are observed and might process that protect against perineal trauma at childbirth. Some data in humans have shown that the risk of perineal trauma is highly linked to the intrinsic characteristics of the tissue, suggesting the potential benefit of incorporating intrinsic biomechanical characteristics in the risk prediction for perineal trauma. Shear wave elastography might be a useful noninvasive tool to investigate the elastic properties of these tissues in pregnant women in vivo, with the goal of implementing these properties as a predictive strategy.