Levator avulsion and vaginal parity: do subsequent vaginal births matter?

Prevalence of levator ani muscle injuries in primiparous women after delivery and their influence on pelvic floor disorders-systematic review

BACKGROUND

Studies show a significant association between the first vaginal delivery and injuries of the levator ani muscle (LAM), which can cause pelvic floor disorders (PFDs).

OBJECTIVES

This study aims to identify the prevalence of short and long-term LAM injuries after vaginal delivery in primiparous women and its influence on PFDs.

METHOD

A systematic review was conducted according to the PRISMA methodology. The databases used were Pubmed, Cochrane, and PEDro. The quality assessment of the evidence was carried out using the Critical Appraisal Skills Programme (CASP). Both the selection of studies and their evaluation were done by two researchers and a third reviewer in cases of disagreement.

RESULTS

From the search, 57 articles were gathered, and 19 were included to match the eligibility criteria. The prevalence of avulsion of the LAM was found in association with vaginal delivery between 13% and 28% ≤ 1 year after delivery and between 16% and 29% > 1 year after delivery. Ballooning was detected between 20% and 37% ≤ 1 year, and 33% of women > 1 year after delivery, appearing to be more common when compared to avulsion. Pelvic organ prolapse (POP) was considered the most common disorder associated with injuries of the LAM, and there seems to be some connection with sexual dysfunction.

CONCLUSION

Avulsion of the LAM and ballooning of the hiatal area have a high prevalence in primiparous women after vaginal delivery and have a strong direct relation to the development of POP.

Association of pre-pregnancy body mass index and gestational weight gain on postpartum pelvic floor muscle morphology and function in Chinese primiparous women: A retrospective cohort study

OBJECTIVE

Our study aimed to investigate the association between maternal pre-pregnancy body mass index (BMI), gestational weight gain (GWG), and impaired pelvic floor muscle (PFM) morphology and function during the early postpartum period.

METHODS

This retrospective cohort study was conducted at Shanghai First Maternity and Infant Hospital from December 2020 to December 2022. A total of 1118 primiparous women with singleton pregnancies who underwent vaginal deliveries and participated in postpartum PFM assessments were included. Maternal pre-pregnancy BMI and GWG were considered as exposures. PFM morphology and function impairment were the primary outcomes. PFM morphology impairment, defined as levator ani muscle avulsion, was assessed using transperineal ultrasound. PFM function impairment, manifested as diminished PFM fiber strength, was assessed through vaginal manometry. Multivariable logistic regression analysis was employed to calculate adjusted odds ratios (aOR) with 95% confidence intervals (CI). Restricted cubic spline models were used to validate and visualize the relationship.

RESULTS

Women with lower pre-pregnancy BMI were at an increased risk of levator ani muscle avulsion (aOR = 1.73, 95% CI: 1.10-2.70, P = 0.017), particularly when combined with excessive GWG during pregnancy (aOR = 3.20, 95% CI: 1.15-8.97, P = 0.027). Lower pre-pregnancy BMI was also identified as an independent predictor of PFM weakness (aOR = 1.53, 95% CI: 1.08-2.16, P = 0.017 for type I fiber injuries). Notably, regardless of the avulsion status, both underweight and overweight/obese women faced an elevated risk of reduced PFM strength (aOR = 1.74, 95% CI: 1.17-2.59, P = 0.006 for underweight women with type I fiber injuries; aOR = 1.67, 95% CI: 1.06-2.64, P = 0.027; and aOR = 1.73, 95% CI: 1.09-2.76, P = 0.021 for overweight/obese women with type I and type II fibers injuries, respectively).

CONCLUSIONS

Both lower and higher pre-pregnancy BMI, as well as excessive GWG, were strongly associated with PFM impairments. These findings highlighted the critical importance of comprehensive weight management throughout pregnancy to effectively promote women's pelvic health.

Obstetric risk factors for levator ani muscle avulsion: A systematic review and meta-analysis

OBJECTIVES

Women have a 11% lifetime risk of undergoing surgery for vaginal prolapse. Levator ani muscle (LAM) avulsion is one etiological factor associated with primary and recurrent pelvic organ prolapse. Pelvic organ prolapse has been shown to greatly affect the quality of life and well-being of women. Conduct a meta-analysis identifying risk factors associated with LAM avulsion recognised on transperineal ultrasound (TPUS) or magnetic resonance imaging (MRI) in primiparous women after vaginal birth.

STUDY DESIGN

OVID Medline, Embase and the Cochrane Library from inception to January 2021 were searched. Review Manager 5.3 (The Cochrane Collaboration) was used to analyse data. Odds ratios (OR) with 95% confidence intervals (95% CIs) were calculated. The heterogeneity among studies was calculated using the I2statistic.

RESULTS

Twenty-five studies were eligible for inclusion (n = 9333 women). Major LAM avulsion was diagnosed in an average of 22 % (range 12.7-39.5 %) of cases. Twenty-two studies used TPUS and three used MRI to diagnose avulsion. Modifiable and non-modifiable risk factors were identified. Significant predictors identified were forceps (OR 6.25 [4.33 - 9.0]), obstetric anal sphincter injuries (OR 3.93 [2.85-5.42]), vacuum (OR 2.41 [1.40-4.16]), and maternal age (OR 1.06 [1.02-1.10]).

CONCLUSIONS

This is the first meta-analysis of both modifiable and non-modifiable risk factors associated with LAM avulsion. This information could be used to develop a clinically applicable risk prediction model to target postnatal women at risk of LAM avulsion with a view to prevent the onset of pelvic floor organ prolapse.

Analysis of questions by patients with pelvic organ prolapse about vaginal pessaries resulting in a checklist for their physicians

OBJECTIVE

International guidelines recommend vaginal pessaries as a first-choice treatment of symptomatic pelvic organ prolapse (POP). Gynecologists rarely receive systematic training or just do not take the time to communicate with their patients. We hypothesized that we could identify key deficits and limitations of counseling before or during pessary therapy from questions directed to manufacturers with the aim to improve and promote health literacy of women with POP.

METHODS

We approached five manufacturers to provide anonymized inquiries related to pessary use. After exclusion of duplicates and questions about obstetric pessaries, 174 data sets from 145 patients remained.

RESULTS

In 19/145 patients (13.1%), a 2nd degree, and in 94/145 (64.8%), a 3rd-4th degree of POP was identified. Four patients had additional urinary incontinence. In 32/145 (22.1%), the severity of POP could not be identified. The age of patients ranged from 27 to 98 (mean = 63.7) years. Most inquiries were related to the selected pessary models or sizes (40/174; 22.9%), self-management (20/174; 11.5%), and technical aspects such as shelf life or appropriate cleaning (26/174; 14.9%). Pain or voiding dysfunction was present in 17/174 remarks (9.7%). Lifestyle questions related to the use of pessaries during sport, menstruation, or mechanical anticonception. The cube pessary was in the focus of interest followed by the sieve bowl, urethra, ring, and Gellhorn device. The list of questions was summarized as a checklist stratified according to priorities.

CONCLUSION

The checklist should help improve counseling and self-management of patients to optimize the benefit/risk ratio of conservative treatment of pelvic floor diseases.

Diagnosis of maternal birth trauma by pelvic floor ultrasound

BRIEF SUMMARY

Maternal somatic birth trauma due to vaginal delivery is more common than generally assumed and an important cause of future morbidity. Maternal birth trauma may involve both psychological and somatic morbidity, some of it long-term and permanent. Somatic birth trauma is now understood to encompass not just episiotomy, perineal tears and obstetric anal sphincter injuries (OASI), but also trauma to the levator ani muscle, termed 'avulsion'. This review will focus on recent developments in the imaging diagnosis of maternal birth trauma, discuss the most important risk factors and strategies for primary and secondary prevention. Translabial and exo-anal ultrasound allow the assessment of maternal birth trauma in routine clinical practice and enable the use of levator avulsion and anal sphincter trauma as key performance indicators of maternity services. This is likely to lead to a greater awareness of maternal birth trauma amongst maternity caregivers and improved outcomes for patients, not the least due to an increasing emphasis on patient autonomy and informed consent in antenatal and intrapartum care.

Is age at menarche a predictor of maternal birth trauma?

OBJECTIVE

Age at menarche and the interval between menarche and age at first vaginal birth have been shown to be associated with reproductive performance; however, their association with maternal birth trauma has not been studied. We aimed to determine whether age at menarche, age at first vaginal birth and their interval are associated independently with levator ani muscle (LAM) avulsion and external anal sphincter (EAS) defect.

METHODS

This was a retrospective analysis of the ultrasound volume datasets of 466 vaginally parous patients attending one of two tertiary urogynecological units in Australia. All patients had undergone a standardized interview and clinical examination using the pelvic organ prolapse quantification staging system, followed by four-dimensional translabial ultrasound. Tomographic ultrasound imaging was used to evaluate the LAM for avulsion and the EAS for significant defect.

RESULTS

Of the 466 women analyzed, LAM avulsion was diagnosed in 121 (26.0%) and significant EAS defect in 55 (11.8%). Logistic regression analysis showed no association between age at menarche and LAM avulsion (P = 0.67). Weak but significant associations were noted between LAM avulsion and age at first vaginal birth (odds ratio (OR), 1.070 (95% CI, 1.03-1.11); P = 0.0007) and between LAM avulsion and menarche-to-first-vaginal-birth interval (OR, 1.064 (95% CI, 1.02-1.11); P = 0.0018). No significant associations were noted between significant EAS defect and any of the evaluated variables (all P ≥ 0.49).

CONCLUSIONS

Age at menarche is not predictive of maternal birth trauma i.e. LAM avulsion and EAS residual defect. There was a statistically significant association between LAM avulsion and menarche-to-first-vaginal-birth interval; however, this was not stronger than the previously established association between LAM avulsion and age at first vaginal birth, arguing against any distinct effect of prolonged prepregnancy hormonal stimulation on the biomechanical properties of the pelvic floor. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

A biomechanical study of the birth position: a natural struggle between mother and fetus

Birth trauma affects millions of women and infants worldwide. Levator ani muscle avulsions can be responsible for long-term morbidity, associated with 13-36% of women who deliver vaginally. Pelvic floor injuries are enhanced by fetal malposition, namely persistent occipito-posterior (OP) position, estimated to affect 1.8-12.9% of pregnancies. Neonates delivered in persistent OP position are associated with an increased risk for adverse outcomes. The main goal of this work was to evaluate the impact of distinct fetal positions on both mother and fetus. Therefore, a finite element model of the fetal head and maternal structures was used to perform childbirth simulations with the fetus in the occipito-anterior (OA) and OP position of the vertex presentation, considering a flexible-sacrum maternal position. Results demonstrated that the pelvic floor muscles' stretch was similar in both cases. The maximum principal stresses were higher for the OP position, and the coccyx rotation reached maximums of 2.17[Formula: see text] and 0.98[Formula: see text] for the OP and OA positions, respectively. Concerning the fetal head, results showed noteworthy differences in the variation of diameters between the two positions. The molding index is higher for the OA position, with a maximum of 1.87. The main conclusions indicate that an OP position can be more harmful to the pelvic floor and pelvic bones from a biomechanical point of view. On the other side, an OP position can be favorable to the fetus since fewer deformations were verified. This study demonstrates the importance of biomechanical analyses to further understand the mechanics of labor.

Natural history of levator ani muscle avulsion 4 years following childbirth

OBJECTIVES

The primary aim was to evaluate prospectively the natural history of levator ani muscle (LAM) avulsion 4 years following first delivery and its correlation with signs and symptoms of pelvic floor dysfunction (PFD). The secondary aim was to investigate the effect of a second vaginal delivery on the incidence of LAM avulsion and PFD.

METHODS

This was a prospective longitudinal study of nulliparous women recruited antenatally, who were assessed at 36 weeks' gestation and 3 months, 1 year and 4 years postpartum for signs and symptoms of PFD and presence of LAM avulsion. Pelvic floor muscle strength was assessed by digital palpation, and pelvic organ prolapse (POP) was assessed using the POP quantification (POP-Q) system. Validated questionnaires were used to evaluate urinary, bowel and sexual function and symptoms of POP. Transperineal ultrasound was performed to assess LAM integrity and hiatal biometry. Differences in signs and symptoms of PFD over time were evaluated using a linear mixed model, separately in women who had had one delivery and in those who had two or more deliveries during the study period.

RESULTS

Of 269 women recruited, 147 (55%) attended the 4-year follow-up and were examined at a mean interval of 3.8 ± 0.4 years after their first delivery. Of these, 74 (50%) had a subsequent delivery. The prevalence of LAM avulsion 4 years after a first vaginal delivery was 13%, with no difference between women who had one and those who had two or more vaginal deliveries. Women with an intact LAM and one or more deliveries showed no change in signs and symptoms of PFD at 4 years compared with the previous assessments. Of women with one vaginal delivery who were diagnosed with LAM avulsion 3 months or 1 year postpartum, those in whom the LAM avulsion was no longer evident at 4 years (42%) showed worsening of POP-Q measurements, whereas those with persistent LAM avulsion (58%) showed significant worsening in pelvic floor muscle strength and hiatal area on ultrasound. After a second vaginal delivery, no new avulsions were diagnosed, however, previous LAM avulsion became more extensive in 44% of women and hiatal area increased in women with persistent LAM avulsion.

CONCLUSIONS

The first vaginal delivery carries the greatest risk for LAM avulsion, with impact on signs of PFD 4 years later. A second vaginal delivery could result in deterioration of LAM avulsion, but no new avulsions were found. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Ultrasound imaging of maternal birth trauma

INTRODUCTION AND HYPOTHESIS

The term 'maternal birth trauma' has undergone substantial changes in meaning over the last 2 decades. Leaving aside psychological morbidity, somatic trauma is now understood to encompass not just episiotomy, perineal tears and obstetric anal sphincter injuries (OASI), but also trauma to the levator ani muscle. This review covers diagnosis of maternal birth trauma by translabial ultrasound imaging.

METHODS

Narrative review.

RESULTS

Tomographic imaging of pelvic structures with the help of 4D ultrasound, used since 2007, has allowed international standardization and seems to be highly reproducible and valid for the diagnosis of OASI and levator avulsion.

CONCLUSIONS

Translabial and exo-anal ultrasound allows the assessment of maternal birth trauma in routine clinical practice and the utilization of avulsion and sphincter trauma as key performance indicators of maternity services. It is hoped that this will lead to a greater awareness of maternal birth trauma among maternity caregivers and improved outcomes for patients, both in the short term and in the decades to come.

The effect of replacing vacuum with forceps in operative vaginal delivery: an observational study

INTRODUCTION AND HYPOTHESIS

An increase in vaginal delivery with forceps may increase rates of pelvic floor trauma. This study was designed to predict trauma rates resulting from policies preferencing forceps.

METHODS

This is an observational cohort study utilizing data from 660 primiparae enrolled in an RCT in two tertiary obstetric units in Sydney, Australia. Participants were assessed clinically and with 4D translabial ultrasound in the late third trimester and again at 3-6 months postpartum. Incidence of trauma associated with mode of delivery was adjusted to reflect change associated with a conversion of vacuum to forceps delivery. Primary outcome measures were third-/fourth-degree tear, levator avulsion (LA) and external anal sphincter (EAS) trauma diagnosed sonographically.

RESULTS

Five hundred four women were seen at a mean of 5.1 (2.3-24.3) months postpartum. After exclusion of 21 because of missing data, 483 women were analysed: 112 (23%) had a CS, 268 (55%) a normal vaginal delivery (NVD), 69 (14%) a vacuum (VD) and 34 (7%) a forceps (FD). One hundred fifty-two women had EAS trauma and/or LA; 17 sustained both. After VD, 32/69 (46%) women suffered LA and/or EAS trauma; after FD, it was 33/34 (97%). Converting VD to FD was estimated to result in an increase in trauma from 152/483 (31%) to 187/483 (39%). A formula can be generated based on local obstetric and ultrasound data to estimate trauma incidence.

CONCLUSIONS

A change in obstetric practice resulting in the conversion of primary VD to primary FD would be expected to substantially increase the likelihood of pelvic floor trauma.