Change in prevalence of major levator ani muscle defects from 6 weeks to 1 year postpartum, and maternal and obstetric risk factors: A longitudinal ultrasound study

What is known about changes in pelvic floor muscle strength and tone in women during the childbirth pathway? A scoping review

INTRODUCTION

This scoping review aims to comprehensively explore the existing research on the changes in pelvic floor function that occur throughout the childbirth pathway (antenatal, intrapartum, and postnatal period). Furthermore, it seeks to identify new opportunities and directions for future research in this field. In particular, this review focuses on investigating pelvic floor muscle strength and tone in women during the childbirth pathway.

METHODS

The following databases were investigated from their inception: PubMed, OVID, Medline, ScienceDirect, The Cochrane Central Library, Scopus, Web of Science, PEDro, Scholar Google, Embase, and CINHAIL. Literature research was carried out from March to October 2022. Records identified through database searching were imported to Covidence. According to Arksey and O'Malley's five-stage scoping review framework, researchers screen titles and abstracts for eligibility and exclude records that do not meet the inclusion criteria.

RESULTS

A total of 40 studies were included in the data extraction phase. These articles underwent a review, with a specific emphasis on examining the tone, strength, and distensibility of the pelvic floor throughout the childbirth pathway. Among the selected studies, 22 investigated pelvic floor strength, 7 the distensibility, and 3 articles the tone.

CONCLUSIONS

This review identified both areas of agreement and disagreement across all three themes examined, with a particular emphasis on labor and the postpartum period. Notably, the review unveiled a significant scarcity of data concerning the tone of pelvic floor muscles throughout the childbirth pathway. Further studies to investigate the relationship between midwifery care and pelvic floor outcomes are required to improve clinical practice.

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.

Postpartum pelvic floor muscle training, levator ani avulsion and levator hiatus area: a randomized trial

INTRODUCTION AND HYPOTHESIS

Vaginal delivery may lead to tearing of the levator ani (LA) muscle from its bony insertions (complete LA avulsion) and increased levator hiatus (LH) area, both risk factors for pelvic floor dysfunctions. Early active rehabilitation is standard treatment after musculo-skeletal injury. We hypothesized that pelvic floor muscle training (PFMT) early postpartum would reduce the presence of LA avulsions and reduce LH area.

METHODS

We carried out a planned secondary analysis from a randomized controlled study. Primiparous women (n=175) giving birth vaginally were included 6 weeks postpartum, stratified on complete LA avulsion, and thereafter randomized to PFMT or control. The training participants (n=87) attended a supervised PFMT class once a week and performed home-based PFMT daily for 16 weeks. The control participants (n=88) received no intervention. Presence of complete LA avulsion, LH area at rest, maximal contraction, and maximal Valsalva maneuver were assessed by transperineal ultrasound. Between-group comparisons were analyzed by analysis of covariance for continuous data, and relative risk (RR) for categorical data.

RESULTS

Six months postpartum, the number of women who had complete LA avulsion was reduced from 27 to 14 within the PFMT group (44% reduction) and from 28 to 17 within the control group (39% reduction). The between-group difference was not significant, RR 0.85 (95% CI 0.53 to 1.37). Further, no significant between-group differences were found for LH area at rest, during contraction, or Valsalva.

CONCLUSIONS

Supervised PFMT class combined with home exercise early postpartum did not reduce the presence of complete LA avulsion or LH area more than natural remission.

Pelvic floor symptoms from first pregnancy up to 8 years after the first delivery: a longitudinal study

BACKGROUND

Despite the strong association between vaginal childbirth and pelvic floor dysfunction, genetic factors, pregnancy, advancing age, and lifestyle also play a role. The pelvic floor undergoes substantial changes during pregnancy which may contribute to pelvic floor dysfunction. On the other hand, these changes may be favorable to allow for vaginal delivery. However, there is a lack of studies assessing pelvic floor symptoms over time according to delivery mode, which includes women prior to delivery.

OBJECTIVE

The aim of this study was to describe urinary incontinence, vaginal symptoms, and bowel control symptoms from 21 weeks of gestation in the first pregnancy and up to 8 years after the first delivery, stratified by delivery mode.

STUDY DESIGN

This is a longitudinal observational cohort study. 300 nulliparous women were recruited during their first pregnancy. Pelvic floor symptoms were assessed at 21 and 37 weeks of gestation, and 6 weeks, 6 months, 12 months and 8 years after first delivery using the International Consultation on Incontinence Questionnaire (ICIQ) modules: the urinary incontinence sum score; the weighted vaginal symptom sum score; the vaginal-associated quality of life score; the bowel control sum score; and the bowel-associated quality of life sum score. Delivery mode at first delivery defined delivery groups as: normal vaginal, operative vaginal and cesarean delivery. A linear mixed model analysis was used to assess symptom scores over time and to assess the differences in symptom scores between the delivery groups.

RESULTS

Of the 300 women included in the study, of which 193 attended the 8-year follow-up. Pelvic floor symptoms differed in women with vaginal and cesarean delivery. The symptom scores showed a non-linear statistically significant trend. In women, who delivered vaginally, there was an increase of urinary incontinence and vaginal symptom scores already during pregnancy. In women, who later delivered by cesarean, there was a decrease of symptoms scores during pregnancy, and overall lower symptom scores compared to women with vaginal delivery until 12 months after first delivery. Pelvic floor symptoms scores increased from 12 months to 8 years after the first delivery and exceeded pregnancy levels in all delivery groups, however overall symptom scores were low. Differences between delivery groups were not statistically significant.

CONCLUSION

Pelvic floor symptoms differed in women with vaginal and cesarean delivery from the first pregnancy up to 8 years after the first delivery. These differences were recognizable already prior to first delivery.

The evolution of levator ani muscle trauma over the first 9 months after vaginal birth

INTRODUCTION AND HYPOTHESIS

The objective was to investigate the evolution of levator ani muscle (LAM) trauma over the first 9 months after birth and to evaluate their agreement between different assessment periods.

METHODS

From March 2017 to April 2019 we prospectively evaluated LAM states (intact, hematoma, partial or complete avulsion) of primiparous women after vaginal birth by using 4D translabial ultrasound (TLUS) at three different assessment periods. All women were examined 1-4 days (A1) and 6-10 weeks (A2) postpartum, and women with a trauma additionally 6-9 months postpartum (A3). Cohen's Kappa analysis was performed to evaluate the test agreement between the assessment periods.

RESULTS

Thirty-two percent of the women at A1 had a LAM trauma and 24% at A2. The higher number of LAM injuries at A1 can be explained by hematomas (14%), of which 51% spontaneously resolved at A2, 35% revealed themselves as partial, and 12% as complete avulsions. At A3, we observed anatomical improvement from complete to partial avulsions (23%) and few partial avulsions changed into an intact LAM (3%); none of the complete avulsions changed into an intact LAM. The agreement of 4D TLUS between A1 and A2 was moderate to good (0.64 for the right-sided LAM/0.60 for the left-sided LAM) and between A2 and A3 good to very good (0.76 right-sided/0.84 left-sided).

CONCLUSIONS

Levator ani muscle trauma can reliably be diagnosed during all assessment periods. However, the agreement between A1 and A2 was only moderate to good. This can be explained by hematomas inside the LAM that were only observed early postpartum. We observed some anatomical improvement at A3, but no complete avulsion improved to an intact LAM.

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.

Surface electromyography of the pelvic floor at 6-8 weeks following delivery: a comparison of different modes of delivery

INTRODUCTION AND HYPOTHESIS

The objective of this study was to compare the impact of different modes of delivery, especially forceps delivery (FD), on pelvic floor muscles (PFMs) through vaginal surface electromyography (sEMG) in primiparous women at early (6-8 weeks) postpartum.

METHODS

A total of 1259 primiparous women with full-term singleton births were included in this cross-sectional study. Of these, 98 were delivered by forceps, 865 underwent spontaneous vaginal delivery (SD) and 296 underwent elective cesarean delivery (CD). Clinical demographic characteristics and vaginal sEMG variables of parturients 6-8 weeks after birth were collected and analyzed using SPSS software. One-way ANOVA with Bonferroni correction, Chi-square test or Student's t-test was used according to the variable type. Spearman correlation and binary logistic regression analyses were also used. P/α ≤ 0.05 was considered statistically significant.

RESULTS

Amplitude of fast and sustained contractions on sEMG in the FD group was significantly lower compared with the CD and SD groups. The sEMG amplitude of all contractions was significantly higher in the CD group compared with the FD and SD groups (P < 0.01). According to binary logistic regression analysis, mode of delivery was a major influencing factor in sEMG.

CONCLUSIONS

An early postpartum sEMG test appears to be helpful for the assessment of PFM activity. Mode of delivery was a major influencing factor on sEMG. Forceps delivery significantly inversely influenced PFM activity.