Association between levator hiatal dimensions on ultrasound during first pregnancy and mode of delivery

Soft-tissue dystocia due to paradoxical contraction of the levator ani as a cause of prolonged second stage: concept, diagnosis, and potential treatment

Smaller pelvic floor dimensions seem to have been an evolutionary need to provide adequate support for the pelvic organs and the fetal head. Pelvic floor dimension and shape contributed to the complexity of human birth. Maternal pushing associated with pelvic floor muscle relaxation is key to vaginal birth. Using transperineal ultrasound, pelvic floor dimensions can be objectively measured in both static and dynamic conditions, such as pelvic floor muscle contraction and pushing. Several studies have evaluated the role of the pelvic floor in labor outcomes. Smaller levator hiatal dimensions seem to be associated with a longer duration of the second stage of labor and a higher risk of cesarean and operative deliveries. Furthermore, smaller levator hiatal dimensions are associated with a higher fetal head station at term of pregnancy, as assessed by transperineal ultrasound. With maternal pushing, most women can relax their pelvic floor, thus increasing their pelvic floor dimensions. Some women contract rather than relax their pelvic floor muscles under pushing, which is associated with a reduction in the anteroposterior diameter of the levator hiatus. This phenomenon is called levator ani muscle coactivation. Coactivation in nulliparous women at term of pregnancy before the onset of labor is associated with a higher fetal head station at term of pregnancy and a longer duration of the second stage of labor. In addition, levator ani muscle coactivation in nulliparous women undergoing induction of labor is associated with a longer duration of the active second stage of labor. Whether we can improve maternal pelvic floor relaxation with consequent improvement in labor outcomes remains a matter of debate. Maternal education, physiotherapy, and visual feedback are promising interventions. In particular, ultrasound visual feedback before the onset of labor can help women increase their levator hiatal dimensions and correct levator ani muscle coactivation in some cases. Ultrasound visual feedback in the second stage of labor was found to help women push more efficiently, thus obtaining a lower fetal head station at ultrasound and a shorter duration of the second stage of labor. The available evidence on the role of any intervention aimed to aid women to better relax their pelvic floor remains limited, and more studies are needed before considering its routine clinical application.

Validation of an automated software (Smartpelvic™) in assessing hiatal area from three dimensional transperineal pelvic volumes of pregnant women: comparison with manual analysis

OBJECTIVES

The aim of this investigation was to evaluate the agreement between a manual and an automatic technique in assessing levator hiatus area (LHA) during pregnancy from three-dimensional (3D) pelvic floor volumes obtained by trans-perineal ultrasound (TPUS).

METHODS

3D volumes were acquired during rest, maximum pelvic floor contraction and Valsalva maneuver from 66 pregnant women. Manual selection of LHA and automatic software (Smart Pelvic™) were applied on TPUS volume starting from a C-plane view. To evaluate intra- and inter-observer variability measurements of LHA were performed twice by the same operator and once by a second sonographer. Reference hiatal contours obtained manually by the first operator were compared with the automated ones. Reproducibility was evaluated by intraclass correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

LHA measurement, using automatic software, achieved excellent intra-observer and inter-observer reproducibility in pregnant women both at rest and after dynamic analysis (ICC>0.9). Further, an excellent agreement resulted between manual selection of the LHA and automatic imaging (ICC>0.9). The average time taken to obtain LHA manually was significantly longer when compared to the automatic analysis (p≤0.0001).

CONCLUSIONS

Smart pelvic software resulted from a reliable method for automatically measuring the LHA, showing high reproducibility and accuracy.

Factors associated with spontaneous vaginal birth in nulliparous women: A descriptive systematic review

PROBLEM

Spontaneous vaginal birth (SVB) rates for nulliparous women are declining internationally.

BACKGROUND

There is inadequate understanding of factors affecting this trend overall and limited large-scale responses to improve women's opportunity to birth spontaneously.

AIM

To undertake a descriptive systematic review identifying factors associated with spontaneous vaginal birth at term, in nulliparous women with a singleton pregnancy.

METHODS

Quantitative studies of all designs, of nulliparous women with a singleton pregnancy and cephalic presentation, who experienced a SVB at term were included. Nine databases were searched (inception to October 2022). Two reviewers undertook quality appraisal; Randomised Controlled Trials (RCTs) with high risk of bias (ROB 2.0) and other designs with (QATSDD) scoring ≤ 50% were excluded.

FINDINGS

Data were abstracted from 90 studies (32 RCTs, 39 cohort, 9 cross-sectional, 4 prevalence, 5 case control, 1 quasi-experimental). SVB rates varied (13%-99%). Modifiable factors associated with SVB included addressing fear of childbirth, low impact antenatal exercise, maternal positioning during second-stage labour and midwifery led care. Complexities arising during pregnancy and regional analgesia were shown to decrease SVB and other interventions, such as routine induction of labour were equivocal.

DISCUSSION

Antenatal preparation (low impact exercise, childbirth education, addressing fear of childbirth) may increase SVB, as does midwifery continuity-of-care. Intrapartum strategies to optimise labour progression emerged as promising areas for further research.

CONCLUSION

Declining SVB rates may be improved through multi-factorial approaches inclusive of maternal, fetal and clinical care domains. However, the variability of SVB rates testifies to the complexity of the issue.

Does transperineal ultrasound predict the risk of perineal trauma in women with term pregnancy? A prospective observational study

PURPOSE

This study was conducted to evaluate the prevalence of perineal trauma during childbirth and to assess the correlations of the pelvic floor dimensions and fetal head station with obstetric trauma in a prospectively recruited cohort of women.

METHODS

The study included women with a gestational age of at least 37 weeks, who were carrying a single fetus in a cephalic presentation. Transperineal ultrasound (TPU) was performed prior to the onset of labor or labor induction. The purpose was to measure the anteroposterior diameter (APD) of the levator ani muscle (LAM) and the angle of progression, at both rest and maximum Valsalva maneuver. The head-perineum distance was assessed only at rest.

RESULTS

A total of 296 women were included. Of the 253 women who delivered vaginally, 19% (48/253) experienced no perineal trauma, 18.2% (46/253) received an episiotomy during childbirth, 34.4% (87/253) sustained a first-degree laceration, 25.3% (64/253) had a second-degree laceration, and 3.2% had a third- or fourth-degree laceration (8/253). Women with episiotomy had a significantly shorter median APD under Valsalva than women without perineal trauma. Furthermore, women with LAM coactivation (identified by a negative difference between the APD at Valsalva and the APD at rest) were approximately three times more likely to undergo an operative vaginal delivery and over five times more likely to sustain a third- or fourth-degree tear during childbirth than women who exhibited normal relaxation of the LAM during the Valsalva maneuver.

CONCLUSION

TPU may predict the risk of perineal trauma in women with term pregnancy during childbirth.

Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study

INTRODUCTION

There is limited evidence about changes in the pelvic floor during active labor. We aimed to investigate changes in hiatal dimensions during the active first stage of labor and associations with fetal descent and head position.

MATERIAL AND METHODS

We conducted a longitudinal, prospective cohort study at the National University Hospital of Iceland, from 2016 to 2018. Nulliparous women with spontaneous onset of labor, a single fetus in cephalic presentation, and gestational age ≥37 weeks were eligible. Fetal position was assessed with transabdominal ultrasound and fetal descent was measured with transperineal ultrasound. Three-dimensional volumes were acquired from transperineal scanning at the start of the active phase of labor and in late first stage or early second stage. The largest transverse hiatal diameter was measured in the plane of minimal hiatal dimensions. The levator urethral gap was measured as the distance between the center of the urethra and the levator insertion using tomographic ultrasound imaging. Measurements of the levator urethral gap were made in the plane of minimal hiatal dimensions and 2.5 and 5 mm cranial to this.

RESULTS

The final study population comprised 78 women. The mean transverse hiatal diameter increased 12.4% between the two examinations, from 39.4 ± 4.1 mm (±standard deviation) at the first examination to 44.3 ± 5.8 mm at the last examination (p < 0.01). We found a moderate correlation between the transverse hiatal diameter and fetal station at the last examination (r = 0.44, r2  = 0.19; p < 0.01; regression equation y = 2.71 + 0.014x), and a weak correlation between the change in transverse hiatal diameter and change in fetal station (r = 0.29; r2  = 0.08; p = 0.01; regression equation y = 0.24 + 0.012x). Levator urethral gap increased significantly in all three planes on both the left and right sides. Head position was not associated with hiatal measurements after adjusting for fetal station.

CONCLUSIONS

We found a significant, but only modest, increase of the hiatal dimensions during the first stage of labor. The risk of levator ani trauma will therefore be low during this stage. The change in transverse hiatal diameter was associated with fetal descent but not with head position.

Factors involved in changes in the levator ani during pregnancy

INTRODUCTION AND HYPOTHESIS

Levator ani muscle (LAM) dimensions increase during pregnancy to allow the delivery of the fetus. The objective was to investigate which factors are involved in LAM modifications during pregnancy.

METHODS

A prospective longitudinal observational study was conducted between July 2015 and March 2018. Ninety-nine nulliparous pregnant women were included. Data on the physical examination, 4D transperineal ultrasound and hormonal concentrations (progesterone, oestradiol and relaxin) were collected during the first and third trimesters.

RESULTS

We found higher hiatal dimensions at the beginning of pregnancy than in other studies with nonpregnant women. Increases in the levator ani hiatal (LH) dimensions were observed at contraction (1.01 ±1.96 cm2), rest (0.82 ± 2.51 cm2) and on Valsalva (2.36 ± 3.64 cm2) throughout pregnancy. The distensibility in the third trimester was higher than in the first trimester (5.79 vs 4.24 cm2; p=0); however, the contractility was lower (-3.32 vs -3.5 cm2; p=0.04). Women with lower scores on the Modified Oxford Grading Scale in the third trimester presented with lower contractility in the LAM. A larger LH at the end of pregnancy was associated with age and body mass index. Eleven women developed ballooning during pregnancy; in these women, relaxin was higher in both trimesters than in women without ballooning, but these results were not statistically significant. The linear models to predict third-trimester Valsalva LH, distensibility and contractility were not conclusive and did not show any factors to predict LAM modifications during pregnancy.

CONCLUSIONS

Hormones could play a role in modifying the muscle properties of LAM from the beginning of pregnancy, but we did not find an association between LAM measurements and hormone concentration in this study.

Assessment of Pelvic Floor Disorders due to the Gestational Diabetes Mellitus Using Three-Dimensional Ultrasonography: A Narrative Review

Gestational diabetes mellitus (GDM)is an entity with evolving conceptual nuances that deserve full consideration. Gestational diabetes leads to complications and adverse effects on the mother's and infants' health during and after pregnancy. Women also have a higher prevalence of urinary incontinence (UI) related to the hyperglycemic status during pregnancy. However, the exact pathophysiological mechanism is still uncertain. We conducted a narrative review discussing the impact of GDM on the women's pelvic floor and performed image assessment using three-dimensional ultrasonography to evaluate and predict future UI.

Are levator hiatal dimensions in mid-pregnancy associated with mode of delivery?

INTRODUCTION AND HYPOTHESIS

Slow progress of labour is a risk for operative delivery. Smaller levator hiatal dimensions are possible risk factors for slow progress and operative delivery. Our aim was to explore associations between hiatal dimensions antenatally, duration of second stage of labour and mode of delivery.

METHODS

Prospective cohort study of 65 nullipara examined at 20 weeks gestation and 6 months postpartum. Levator hiatal anteroposterior diameter and area were measured using 2D/3D transperineal ultrasound and compared between women with normal vaginal delivery and operative delivery (vacuum or caesarean) using t-test and with Spearman's rank to explore correlations with duration of second stage. ROC analysis established a cut-off for high risk of operative delivery.

RESULTS

Two-dimensional anteroposterior diameter and 3D hiatal area at rest were smaller in women with operative delivery than with normal delivery, 5.0 cm vs. 5.7 cm, p = 0.007 and 18.5 cm² vs. 14.9 cm², p < 0.001. From the ROC curve for 2D anteroposterior diameter, a cut-off of 5.6 cm, (sensitivity = 0.94, specificity = 0.63) and for 3D hiatal area a cut-off of 17.6 cm² (sensitivity = 0.94, specificity = 0.65) predicted operative delivery. We found inverse correlations between second stage of labour and anteroposterior diameter at rest, r = -0.330, contraction, r = -0.365, area at rest, r = -0.324, and contraction, r = -0.521, all p < 0.05.

CONCLUSIONS

Smaller hiatal dimensions at 20 weeks gestation were associated with longer second stage of labour and increased risk of operative delivery in nullipara. A 2D anteroposterior hiatal diameter < 5.6 cm and 3D hiatal area < 17.6 cm² at rest imply increased risk of operative delivery.

The correlation between levator ani co-activation and fetal head regression on maternal pushing at term

OBJECTIVE

To assess the correlation between fetal head regression and levator ani muscle (LAM) co-activation under Valsalva maneuver.

STUDY DESIGN

This study was a secondary analysis of a prospective cohort study on the association between the angle of progression (AoP) and labor outcome. We scanned a group of nulliparous women at term before the onset of labor at rest and under maximum Valsalva maneuver. In addition to the previously calculated AoP, in the present study, we measured the anteroposterior diameter of LAM hiatus (APD) on each ultrasound image. LAM co-activation was defined as APD at Valsalva less than that at rest, whereas fetal head regression was defined as AoP at Valsalva less than that at rest. We calculated the correlation between the two phenomena. Finally, we examined various labor outcomes according to the presence, absence, or co-existence of these two phenomena.

RESULTS

We included 469 women. A total of 129 (27.5%) women presented LAM co-activation while 50 (10.7%) showed head regression. Only 15 (3.2%) women showed simultaneous head regression and LAM co-activation. Women with coexisting LAM co-activation and head regression had the narrowest AoP at Valsalva in comparison with other study groups (p < .001). In addition, they had the highest risk of Cesarean delivery (40%) and longest first, second, and active second stage durations, although none of these reached statistical significance.

CONCLUSION

In nulliparous women at term before the onset of labor fetal head regression and LAM co-activation at Valsalva are two distinct phenomena that uncommonly coexist.

Application of pelvic floor ultrasound during pregnancy to detect patients at risk of cesarean section due to failure of labor progression in a Spanish population

OBJECTIVE

Our study is aimed at evaluating the characteristics of the pelvic floor, assessed through transperineal ultrasound, since it may influence or increase the possibility of having a cesarean delivery, with the objective of acting on those variables that can be modified during pregnancy.

STUDY DESIGN

Transperineal ultrasound was performed on 109 primiparous pregnant women in their first trimester of pregnancy, recruited between May 2018 and February 2019, with the purpose of studying the hiatus area at rest, retention and Valsalva. We have reassessed them at the end of pregnancy and delivery data were recorded. We selected 8 patients as case-study, who had cesarean section delivery due to failure of labor progression. We selected 4 control-cases for each, reaching the total of 32 controls, with similar age and body mass index, to avoid obtaining a biased result from these data.

RESULTS

In the study of hiatal areas, patients who delivered by cesarean section had a smaller hiatal area at rest, during levator ani muscle contraction and during Valsalva maneuver, at all visits. In early pregnancy, the range of the resting hiatal area was 13.8 ± 2.0 cm² for cesarean sections, compared to 16.2 ± 2.7 cm² for vaginal deliveries with an OR of 0.57 (0.34-0.95, 95% CI). For hiatal area on Valsalva, the OR was 0.55 (0.35-0.88, 95% CI). Therefore, the smaller the hiatal area, the greater the possibility of cesarean section. At the end of pregnancy, between 34 and 36 weeks of gestation, the OR of hiatal area on Valsalva was 0.78 (0.60-1.00, 95% CI).

CONCLUSION

The hiatus area measured by transperineal ultrasonography at the beginning and at the end of the pregnancy may be useful to identify the patients who are at a higher risk of cesarean delivery due to failure of labor progression.

The maternal pelvic floor and labor outcome

Vaginal birth is the major cause of pelvic floor damage. The development of transperineal ultrasound has improved our understanding of the relationship between vaginal birth and pelvic floor dysfunction. The female pelvic floor dimensions and function can be assessed reliably in pregnant women. Maternal pushing associated with pelvic floor muscle relaxation is the central requirement of vaginal birth. Many studies have evaluated the role of the pelvic floor on labor outcomes. Smaller levator hiatal dimensions and incomplete or absent levator ani muscle relaxation seem to be associated with a longer duration of the second stage of labor and a higher risk of cesarean and operative deliveries. Here, we presented an overview of the current knowledge of the correlation between female pelvic floor dimension and function, as assessed by transperineal ultrasound, and labor outcome.

Echogenicity of puborectalis muscle, cervix and vastus lateralis muscle in pregnancy in relation to mode of delivery

OBJECTIVES

To confirm our previous observation that levator hiatal dimensions and mean echogenicity of the puborectalis muscle (MEP) are significantly different at 12 weeks' gestation in women who delivered by Cesarean section due to failure to progress compared with those who delivered vaginally. The secondary objective was to assess the association between the echogenicity of the cervix and vastus lateralis muscle and mode of delivery.

METHODS

In this prospective multicenter study, 306 nulliparous women with a singleton pregnancy underwent ultrasound assessments of the pelvic floor at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva maneuver, of the cervix and of the vastus lateralis muscle at 12 weeks' gestation. Dimensions of the levator hiatus, MEP and mean echogenicity of the cervix and vastus lateralis muscle were measured and compared according to mode of delivery.

RESULTS

Two hundred and forty-nine women were included in the analyses. We were unable to confirm our previous finding that MEP and levator hiatal transverse diameter and area at 12 weeks' gestation are associated significantly with mode of delivery. In addition, we could not demonstrate a significant association between echogenicity of the cervix or vastus lateralis muscle and mode of delivery. Overall, MEP was a mean of 20 points lower in women in the new database as compared with the previous study, despite the use of the same ultrasound equipment.

CONCLUSION

In a second, independent multicenter dataset, we were unable to confirm our previous finding that levator hiatal dimensions and MEP on pelvic floor muscle contraction are associated significantly with mode of delivery. We also found no association between echogenicity of the cervix or vastus lateralis and mode of delivery. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

[Cesarean section and perineal protection: CNGOF Perineal Prevention and Protection in Obstetrics Guidelines]

OBJECTIVE

The endpoint was to assess the interest of planned cesarean section in primary and secondary obstetrical perineal prevention.

METHODS

This is a review of the literature about the impact of the mode of delivery in urinary incontinence (UI), anal incontinence (AI), pelvic organ prolapse (POP), sexual disorders de novo or prior to delivery and history of obstetric anal sphincter injuries (OASI).

RESULTS

The studies about UI, AI and sexual disorders report a potential protective impact of cesarean section but with a possible selection bias and an inadequate comparability of the groups. Randomized trials do not report any protective effect of planned cesarean section for these 3 disorders. The literature about POP reports a higher risk for the women who delivered vaginally but still with a possible selection bias et there is no randomized trial for this outcome. About the secondary prevention of OASI, there is no evidence in the literature for a benefit of a systematic planned cesarean section for all women. For symptomatic women, the mode of delivery has to be discussed individually. In secondary prevention of UI, AI, POP and sexual disorders, there is no evidence in the literature for a benefit of planned cesarean section even if there is a history of surgical procedure for the disorder.

CONCLUSION

Planned cesarean section is not recommended in order to prevent primary or secondary obstetrical perineal disorders except for symptomatic OASI for whom an individual discussion about the mode of delivery is recommended.

2D USS of the pelvic floor in the 3rd trimester versus mode of delivery

OBJECTIVE

Biomechanics of pelvic floor muscles is becoming an important field of research in understanding a complex process of labour. Current evidence indicates that the levator ani stretches to allow passage of the fetus through the birth canal. We sought to identify properties of the functional female pelvic floor during pregnancy that could help to predict the mode of delivery, especially in women who underwent caesarean section in the past.

METHODS

A single centre prospective cohort study of pregnant women in the 3rd trimester attending antenatal clinic. Participants were categorised into three groups: 1. nulliparous, 2. previous one vaginal delivery and 3. previous one caesarean section who chose a trial of labour in their current pregnancy. All women underwent ultrasonographic evaluation of their pelvic floor muscles. Distensibility and the mode of delivery were assessed in participants' current pregnancies. The primary outcome was the mode of delivery. ANOVA test was used for statistical analysis.

RESULTS

133 women were included: 55 nulliparous, 52 primiparous (previous one vaginal birth), and 26 primiparous (previous one LSCS and planned for vaginal delivery after caesarean (VBAC)). Participants were scanned at an average gestation of 32 weeks. The inter-observer reliability test for puborectalis distensibility was good (kappa 0.75). Overall, women who delivered vaginally had a more distensible puborectalis muscle than those who delivered by emergency LSCS regardless of their previous type of delivery. Women who underwent a successful VBAC had less distensible pelvic floor muscles compared to their nulliparous and primiparous counterparts (who delivered vaginally in the past).

CONCLUSION

These results support our basic conceptual theory of puborectalis muscle distensibility influencing the mode of delivery and endorse application of dynamic pelvic floor ultrasound in future studies. We identified measurable differences in the functional female pelvic anatomy aiding a better understanding of physiology of the labour. There are trends towards lesser distensibility in women who delivered by LSCS.

Can We Evaluate Hiatal Ballooning by Measuring the Anteroposterior Diameter With 2-Dimensional Translabial Ultrasonography?

OBJECTIVES

To analyze the association between the anteroposterior hiatal diameter and pelvic organ prolapse and to determine whether 2-dimensional translabial ultrasonography can evaluate hiatal ballooning by measuring the anteroposterior diameter.

METHODS

This study was a retrospective analysis of 312 women seen for lower urinary tract symptoms or pelvic organ prolapse between December 2014 and July 2016. All women had an International Continence Society (ICS) Pelvic Organ Prolapse Quantification (POP-Q) system examination and 4-dimensional translabial ultrasonography. The anteroposterior hiatal diameter was measured in the midsagittal plane, and the hiatal area was measured in the minimal axial plane during the maximal Valsalva maneuver.

RESULTS

Valid data from 294 patients were analyzed. International Continence Society POP-Q stage 0 was found in 121 women, stage 1 in 49, stage 2 in 78, stage 3 in 42, and stage 4 in 4. The anteroposterior diameter had an excellent linear correlation (r = 0.814; P < .001) with the hiatal area during the Valsalva maneuver and was strongly related to ICS POP-Q stages (P < .01). A receiver operating characteristic curve analysis proposed a cutoff of 6.0 cm for the anteroposterior diameter against ICS POP-Q stage 2 and higher (sensitivity, 73%; specificity, 52%) and prolapse symptoms (sensitivity, 74%; specificity, 64%).

CONCLUSIONS

The anteroposterior hiatal diameter, which represents hiatal distensibility in the midsagittal plane, can be used to evaluate hiatal ballooning. "Mild" ballooning was defined as an anteroposterior diameter measurement of 6.0 to less than 6.5 cm, "moderate" ballooning as 6.5 to less than 7.0 cm, and "marked" ballooning as 7.0 cm or greater.

Changes in global strain of puborectalis muscle during pregnancy and postpartum

OBJECTIVE

One of the functional parameters that can be assessed by ultrasound is muscle strain, which represents the extent of deformation of the muscle from its original shape when forces are applied to the tissue under study. The aim of this study was to evaluate the effect of pregnancy and delivery on the puborectalis muscle, by assessing changes in global strain of the muscle during and after pregnancy.

METHODS

This was a secondary analysis of a prospective observational study on the association between stress urinary incontinence and levator ani muscle avulsion after delivery. Two-hundred and eighty nulliparous pregnant women underwent four-dimensional transperineal ultrasound assessments at 12 and 36  weeks of gestation, and 6 months postpartum. Tomographic ultrasound images were constructed and the puborectalis muscle was delineated by hand using programming software. After delineation, the length of the midline of the puborectalis muscle was measured at rest and during maximum pelvic floor muscle contraction, and global strain was expressed as percentile difference. Postpartum results were analyzed separately for vaginal, operative (vacuum) vaginal and Cesarean delivery. Differences in global strain of the puborectalis muscle according to mode of delivery were compared using a paired-sample t-test. The effect of partial or complete avulsion of the puborectalis muscle on postpartum strain was evaluated by ANOVA.

RESULTS

In total, 254 datasets were analyzed. Global strain of the puborectalis muscle did not change during pregnancy, but after spontaneous or operative vaginal delivery the global strain diminished significantly. No significant change was observed in strain of the puborectalis muscle after Cesarean delivery. Women who suffered complete bilateral avulsion had significantly lower strain compared with women with an intact puborectalis muscle.

CONCLUSION

Spontaneous or operative vacuum vaginal birth and complete bilateral avulsion of the puborectalis muscle influence negatively the strain of the puborectalis muscle. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

The Epidemiology of Pelvic Floor Disorders and Childbirth: An Update

Using a lifespan model, this article presents new scientific findings regarding risk factors for pelvic floor disorders (PFDs), focusing on the role of childbirth in the development of single or multiple coexisting PFDs. Phase I of the model includes predisposing factors, such as genetic predisposition and race. Phase II includes inciting factors, such as obstetric events. Prolapse, urinary incontinence (UI), and fecal incontinence (FI) are more common among vaginally parous women, although the impact of vaginal delivery on risk of FI is less dramatic than prolapse and UI. Phase III includes intervening factors, such as age and obesity.

[Changes in pelvic organ mobility and ligamentous laxity during pregnancy and postpartum. Review of literature and prospects]

INTRODUCTION

The role of pregnancy in pelvic floor disorders occurrence remains poorly known. It might exist a link between changes in ligamentous laxity and changes in pelvic organ mobility during this period. Our objective was to conduct a non-systematic review of literature about changes in pelvic organ mobility as well as in ligamentous laxity during pregnancy and postpartum.

METHODS

From the PubMed, Medline, Cochrane Library and Web of Science database we have selected works which pertains clinical assessment of pelvic organ mobility (pelvic organ prolapse quantification), ultrasound assessment of levator hiatus and urethral mobility, ligamentous laxity assessment during pregnancy and postpartum.

RESULTS

Clinical assessments performed in these works show an increase of pelvic organ mobility and perineal distension during pregnancy followed by a recovery phase during postpartum. Pelvic floor imaging shows an increase of levator hiatus area and urethral mobility during pregnancy then a recovery phase in postpartum. Different authors also report an increase of ligamentous laxity (upper and lower limbs) during pregnancy followed by a decrease phase in postpartum.

CONCLUSION

Pelvic organ mobility, ligamentous laxity, levator hiatus and urethral mobility change in a similarly way during pregnancy (increase of mobility or distension) and postpartum (recovery).

LEVEL OF EVIDENCE

3.

Association of First-Trimester Echogenicity of the Puborectalis Muscle With Mode of Delivery

OBJECTIVE

To evaluate the association between mean echogenicity of the puborectalis muscle, measured using transperineal ultrasonography, in women during their first pregnancy and the subsequent mode of delivery.

METHODS

This is a secondary analysis of a prospective observational study on the association between stress urinary incontinence and levator muscle avulsion after delivery of a first pregnancy. In this study, 280 nulliparous women with singleton pregnancies were examined with transperineal ultrasound examination at 12 and 36 weeks of gestation. Patients were recruited from an obstetrics practice associated with the university medical center in Utrecht, the Netherlands. Mean echogenicity of the puborectalis muscle values were measured at rest, in pelvic floor muscle contraction, and during the Valsalva maneuver. The subsequent mode of delivery was classified into five categories: spontaneous vaginal delivery, instrumental vaginal delivery, elective cesarean delivery, cesarean delivery resulting from nonreassuring fetal status, and cesarean delivery resulting from failure to progress. Mean echogenicity of the puborectalis muscle values according to mode of delivery were compared by analysis of variance and Tukey's post hoc test.

RESULTS

Of the 254 women included, 157 had spontaneous vaginal delivery, 47 underwent cesarean delivery (11 elective, 36 emergency), and 45 had vacuum operative vaginal delivery; in five patient files, the mode of delivery was not recorded. Of the analyzed women, those who delivered by cesarean because of failure to progress had a significantly lower mean echogenicity of the puborectalis muscle in pelvic floor contraction at 12 weeks of gestation (mean echogenicity of 116±14) than women who had spontaneous vaginal delivery (132±21; Tukey's post hoc test, P=.03), instrumental vaginal delivery (138±21; P=.004), and cesarean delivery resulting from nonreassuring fetal status (139±20; P=.02).

CONCLUSION

Lower mean echogenicity of the puborectalis muscle values in pelvic floor contraction during the first pregnancy at 12 weeks of gestation is associated with subsequent cesarean delivery as a result of failure to progress.

Reliability of new three-dimensional ultrasound technique for pelvic hiatal area measurement

OBJECTIVE

To assess the reproducibility of a new technique for three-/four-dimensional (3D/4D) ultrasound imaging of the pelvic floor: OmniView™ volume contrast imaging (VCI) for measurement of the pelvic hiatal area on maximum contraction and Valsalva maneuver. In addition, we aimed to study the intermethod agreement between the new technique and the 3D/4D render method.

METHODS

We acquired one static 3D and two dynamic 4D transperineal volumes (one obtained during contraction and one during Valsalva maneuver) from 35 nulliparous asymptomatic healthy volunteers and 35 women with symptoms of pelvic floor dysfunction. Each 3D dataset was analyzed using the OmniView-VCI technique to measure the pelvic hiatal area at rest, on maximum contraction and on maximum Valsalva. Analysis was performed twice by the same operator and once by another operator in order to assess intra- and interobserver reproducibility. All measurements were repeated by one operator using the 3D/4D render method to evaluate the intermethod agreement. Reproducibility and intermethod agreement were studied by means of intraclass correlation coefficients (ICC) and the Bland-Altman method.

RESULTS

Measurement of hiatal area using the OmniView-VCI technique showed excellent intraobserver and interobserver reproducibility in both asymptomatic and symptomatic women at rest, on contraction and on Valsalva maneuver. In addition, excellent agreement was demonstrated between OmniView-VCI and 3D/4D render in both groups (ICCs on Valsalva in asymptomatic and symptomatic women were 0.894 and 0.975, respectively). No systematic difference was noted in any of the reliability studies performed.

CONCLUSIONS

OmniView-VCI is a reliable method for pelvic hiatal area measurement. Both rendering mode and OmniView-VCI can be used interchangeably for assessing pelvic hiatal area. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.