{"paper_id":"4431ba3b-c842-440c-b762-b448a2d2f2e6","body_text":"SYSTEMATIC REVIEW Open Access\n© The Author(s) 2025. Open Access  This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 \nInternational License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you \ngive appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the \nlicensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or \nother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the \nmaterial. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or \nexceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit  h t t p  : / /  c r e a  t i  \nv e c  o m m  o n s .  o r  g / l  i c e  n s e s  / b  y - n c - n d / 4 . 0 /.\nShahAli et al. BMC Women's Health          (2025) 25:542 \nhttps://doi.org/10.1186/s12905-025-04095-2\nBMC Women's Health\n*Correspondence:\nGhazal Kharaji\nghazalkh73@gmail.com\nFull list of author information is available at the end of the article\nAbstract\nBackground Pelvic organ prolapse (POP) is common among women and is associated with bladder, bowel, \nand sexual dysfunction, reducing quality of life. Pelvic floor muscle training (PFMT) is recommended as a first-line \nconservative therapy, but its effects on pelvic floor muscle (PFM) morphometry remain unclear. This is the first \nsystematic review and meta-analysis to evaluate the effects of PFMT on PFM morphometric parameters in women \nwith POP .\nMethods A comprehensive search of PubMed/MEDLINE, Scopus, the Cumulative Index to Nursing and Allied Health \nLiterature (CINAHL), Web of Science, the Cochrane Library, and the Physiotherapy Evidence Database (PEDro) was \nconducted. The study was conducted and reported in accordance with the Preferred Reporting Items for Systematic \nReviews and Meta-Analyses (PRISMA) guidelines. The search strategy covered all records from database inception to \nJuly 9, 2025. Randomized controlled trials (RCTs) and clinical trials assessing PFMT effects on PFM morphometry were \nincluded. Methodological quality was assessed using the PEDro scale. Meta-analyses were performed using random-\neffects and fixed-effects models.\nResults Eight studies with 579 women (POP stages I–III) were included. Meta-analyses based on excellent to low \nquality evidence demonstrated significant reductions in levator hiatus area (LHA) at rest (MD = − 1.97; 95% CI: −2.79 to \n− 1.15; p < 0.0001; 3 studies) and, based on good to low quality evidence, during the Valsalva maneuver (MD = − 2.30; \n95% CI: −3.36 to − 1.25; p < 0.0001; 2 studies). Furthermore, excellent to low quality evidence indicated that PFMT \nimproved bladder neck position (MD = 0.16; 95% CI: 0.08 to 0.23; p < 0.0001; 3 studies).\nNarrative synthesis suggested improvements in PFM strength, while effects on the POP stage were inconsistent across \nstudies. Based on PEDro ratings, the included studies comprised three excellent, one good, two moderate, and two \nlow-quality trials.\nConclusion PFMT may improve PFM morphometry, POP stage, and muscle strength in women with POP . However, \nthe evidence remains limited due to the small number of studies, the low quality of some studies, and the inclusion \nEffect of pelvic floor muscle training on pelvic \nfloor muscle morphometry in subjects \nwith pelvic organ prolapse: a systematic \nreview and meta-analysis\nShabnam ShahAli1, Kari Bø2, Anahita Hejazi3, Hamideh Hashemi1 and Ghazal Kharaji1*\n\nPage 2 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nIntroduction\nPelvic organ prolapse (POP) is a prevalent condition \namong women, characterized by the downward dis -\nplacement of one or more pelvic structures, including \nthe anterior or posterior vaginal wall, the uterus, or the \nvaginal apex [ 1]. The etiology of POP is multifactorial, \nwith advancing age and vaginal childbirth identified as \nthe most significant contributing factors. Reported rates \nof stage II or higher POP range from 18% to 56% within \n3 to 6 months postpartum, with natural remission to be \nexpected [ 2]. Among middle-aged and older women, \nespecially those over 50, the prevalence is estimated to be \nbetween 30% and 60% [ 3, 4]. POP can negatively impact \nbladder, bowel, and sexual function, often leading to con-\nsiderable discomfort and a wide range of symptoms, such \nas a sensation of vaginal bulging, low back pain, increased \nurinary frequency, and a sense of incomplete bowel \nevacuation [1]. These symptoms may interfere with daily \nactivities and significantly reduce the quality of life in \naffected women [ 5, 6]. Beyond individual health, POP is \na major public health concern with broader implications \nfor women’s well-being and socioeconomic burden [7, 8].\nCurrent therapeutic approaches for POP include surgi -\ncal and conservative management, most notably pelvic \nfloor muscle training (PFMT) and pessary. However, the \nlong-term outcomes of surgical treatment remain subop -\ntimal. Recurrence of POP following any POP surgery is \ncommon, with reported recurrence rates ranging from \n6% to 30% [ 9, 10]. Furthermore, the invasive nature of \nsurgery may lead to postoperative complications such as \npelvic pain, dyspareunia, and persistent vaginal bleeding \nor discharge [ 9]. In contrast, growing evidence supports \nPFMT as an effective conservative treatment for reduc -\ning POP symptoms and severity, and it is increasingly \nrecommended as the first-line therapy for women with \nPOP [ 11– 14]. Two primary hypotheses have been pro -\nposed to explain the mechanisms by which PFMT may \nexert its therapeutic effects. The first hypothesis centers \non behavioral modification, specifically, teaching women \nto perform voluntary pelvic floor muscle (PFM) con -\ntractions during activities that increase intra-abdominal \npressure (e.g., coughing), which may help prevent POP \nexacerbation [15, 16]. Although this may provide imme -\ndiate symptomatic relief, it is unlikely to induce lasting \nanatomical changes. The second hypothesis suggests that \nregular PFMT over time results in elevation of the pelvic \norgans and a reduction in the size of the levator hiatus \narea (LHA), thereby enhancing structural support and \npromoting more effective automatic pelvic floor func -\ntion [ 17, 18]. These morphological improvements may \naddress the underlying structural deficits contributing \nto POP , thereby providing a more sustained therapeutic \nbenefit that extends beyond symptom management.\nPrevious studies have identified several morphological \ndifferences in the pelvic floor structures of women with \nPOP compared to those without the condition. These \nalterations include an increased LHA [ 19, 20], a low -\nered position of the bladder neck and rectal ampulla [ 21, \n22], and reduced thickness of the levator ani muscle [ 23, \n24]. Emerging evidence suggests that PFMT may posi -\ntively influence these morphological parameters [ 25– 28]. \nEstablishing the efficacy of such interventions is essential \nfor their clinical recommendation. If PFMT can induce \nmorphological improvements within the pelvic floor, \nit may help modify the underlying pathophysiology of \nPOP and thereby strengthen its role as a rehabilitative \nintervention.\nTo date, only one narrative review has examined the \neffects of PFMT on PFM morphology in women with \nstress urinary incontinence and POP [ 17]. Although that \nreview concluded that PFMT may alter PFM morphology, \nonly two of the ten included studies specifically assessed \nwomen with POP , and most findings were reported for \nmixed populations of women with stress urinary inconti -\nnence and POP . Thus, it remains unclear whether PFMT \ncan induce morphological improvements in the PFM in \nwomen with POP . Therefore, the present study aims to \nsystematically synthesize and critically appraise evidence \nfrom randomized controlled trials (RCTs) and clinical \ntrials that have specifically evaluated the effects of PFMT \non PFM morphometry in women diagnosed with POP .\nMethods\nThis systematic review and meta-analysis was conducted \nand reported in accordance with the Preferred Report -\ning Items for Systematic Reviews and Meta-Analyses \n(PRISMA) guidelines [ 29]. The review protocol was reg -\nistered in the PROSPERO database (registration number: \nCRD420251021705). The study included RCTs and clini -\ncal trials that assessed the effects of PFMT on PFM mor -\nphometry in individuals diagnosed with POP .\nof women with POP stages I–III. High-quality RCTs are needed to address these limitations and identify patient \nsubgroups most likely to benefit.\nTrial registration PROSPERO registration number CRD420251021705.\nKeywords Pelvic organ prolapse, Pelvic floor muscle training, Morphometry, Levator hiatus, Bladder neck position, \nPelvic floor rehabilitation, Systematic review, Meta-analysis\n\nPage 3 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nSearch strategy\nThe electronic databases searched for relevant published \nliterature included PubMed/MEDLINE, Scopus, the \nCumulative Index to Nursing and Allied Health Litera -\nture (CINAHL), Web of Science, the Cochrane Library, \nand the Physiotherapy Evidence Database (PEDro). All \ndatabases were systematically searched from their incep -\ntion through July 9, 2025. Additionally, the reference lists \nof all articles selected for critical appraisal, as well as rel -\nevant grey literature, were screened to identify further \neligible studies. The complete search strategies for MED -\nLINE, Scopus, and Web of Science are detailed in Supple-\nmentary 1.\nThe eligibility criteria were defined using the PICOS \nframework as follows:\nPopulation: Adult women (aged ≥ 18 years) \ndiagnosed with any stage of POP according to the \nPelvic Organ Prolapse Quantification System (POP-\nQ) [30].\nIntervention: Any form of PFMT, including various \ninstructional methods, contraction types, number \nof contractions, and whether the training was \nsupervised or unsupervised. Interventions could be \ndelivered alone or in combination with adjunctive \nmodalities, such as electrical stimulation or \nbiofeedback.\nComparator: Any other intervention or no \ntreatment;\nOutcomes: The primary outcomes in this study \nwere measures of PFM morphometry assessed by \nultrasound imaging and/or Magnetic resonance \nimaging (MRI), including thickness, cross-sectional \narea, and length of the levator ani muscle, pelvic \norgan position, and LHA dimensions. Furthermore, \nin the included studies, POP stage and PFM strength \nwere assessed as secondary outcomes.\nStudy design: RCTs and clinical trials (pre-post test \nstudies and studies with non-randomized control \ngroups).\nOnly peer-reviewed full-text articles published in English \nwere included. Studies were excluded from the systematic \nreview for the following reasons: inclusion of participants \nusing a pessary; lack of analysis or clear description of \nthe variables of interest; and use of PFMT as an adjunct \nto surgical intervention. Other study types, including \nreviews, cross-sectional studies, case series, quasi-exper -\nimental designs, and commentaries, were also excluded.\nStudy selection and data extraction\nOne reviewer performed the database searches and \neliminated duplicate records using EndNote X9.1 soft -\nware. Subsequently, two independent reviewers screened \nthe titles and abstracts to determine the relevance of the \nstudies based on the established inclusion criteria. Full \ntexts of potentially relevant studies were then evaluated \nindependently by the same two reviewers. Any discrep -\nancies between the reviewers were resolved through dis -\ncussion with a third reviewer.\nData extraction was performed independently by two \nreviewers (GK and HH). The existing disagreements were \nresolved via a consensus meeting by the third reviewer \n(SS). The following information was extracted from the \nincluded studies: authors, publication year, country, \nstudy design, sample characteristics (age, mean age), POP \nstage, summary of interventions in treatment and con -\ntrol group, outcomes and measurements used, and main \nresults. To obtain missing data relevant to the analysis, \nemail requests were sent to the corresponding authors of \nthe eligible studies. However, no responses were received.\nMethodological quality assessment\nThe methodological quality of the included studies was \nindependently evaluated by two reviewers (GK and HH) \nusing the PEDro scale. Any discrepancies in scoring \nwere resolved through discussion with a third reviewer \n(SS). The PEDro scale comprises 11 items: the first item \nassesses external validity but is not included in the total \nscore, while the remaining 10 items evaluate internal \nvalidity. Each item is scored as 1 point if the criterion is \nmet (“yes”) and 0 if it is not met (“no”). The overall qual-\nity score is calculated by summing the points from the \nten scored items. Studies were categorized based on their \ntotal score as follows: excellent quality (scores 9–10), \ngood quality (scores 6–8), moderate quality (scores 4–5), \nand low quality (scores below 4) [31].\nStatistical analysis\nAll analyses were conducted using Stata MP version 17 \n(StataCorp, College Station, TX, USA). Statistical het -\nerogeneity among studies was assessed using the I² sta -\ntistic, with values exceeding 50% indicating substantial \nheterogeneity. When statistical heterogeneity was low \n(I² < 50%), a fixed-effect inverse-variance model was \nemployed. In the presence of substantial heterogeneity \n(I² ≥ 50%), a random-effects model using the restricted \nmaximum likelihood (REML) method was applied to \nminimize potential bias [ 32]. Accordingly, the random-\neffects REML model was used to evaluate the effective -\nness of PFMT on LHA at rest and bladder neck position, \nwhereas the fixed-effect inverse-variance model was \napplied for assessing PFMT effectiveness during the Val -\nsalva maneuver.\nEffect sizes were calculated as mean differences \nbetween baseline and post-intervention values. Forest \nplots with 95% confidence intervals (CI) were gener -\nated to visualize pooled effects. The magnitude of effect \n\nPage 4 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nsizes was interpreted using the following thresholds: \n< 0.20: trivial; 0.20–0.60: small; 0.61–1.20: moderate; \n1.21–2.00.21.00: large; 2.01–4.00.01.00: very large; >4.00: \nalmost perfect [33].\nAssessment of publication bias and meta-regression \nanalysis was not possible due to the small number of \nincluded studies. A p-value of less than 0.05 was consid -\nered indicative of potential publication bias.\nResults\nAn initial search across all databases yielded 206 stud -\nies. Following the removal of duplicates, 98 citations \nremained. Of these, 87 were excluded based on title and \nabstract screening. Eleven articles were retrieved for full-\ntext assessment, resulting in the exclusion of three stud -\nies. Consequently, eight studies met the inclusion criteria \nand were incorporated into this systematic review and \nmeta-analysis [5, 25– 28, 34– 36]. The study selection pro-\ncess is illustrated in the PRISMA flowchart (Fig. 1).\nAmong the eight included studies investigating mor -\nphological changes following PFMT in women with POP , \nthree were clinical trials [ 5, 27, 36] and five were RCTs \n[25, 26, 28, 34, 35]. Notably, two publications originated \nfrom a single RCT, reporting different outcomes [ 25, \n26]. Of the three clinical trials, two employed a pre–post \ndesign without a control group [ 27, 36], while one study \nincluded two non-randomized groups [5].\nThe included studies were analyzed using three meta-\nanalyses and two narrative syntheses. The first meta-\nanalysis included three studies that evaluated the effects \nof PFMT on the LHA at rest [5, 27, 37]. The second meta-\nanalysis incorporated two studies examining the effects \nof PFMT on the LHA during the Valsalva maneuver [ 5, \n27], and the third meta-analysis included two studies on \nthe effects of PFMT on the bladder neck position [27, 35]. \nIn addition, narrative systematic reviews were conducted \nto summarize the effects of PFMT on the POP stage [ 25, \n27, 35, 36] and PFM strength [25– 28, 35, 36].\nFig. 1 Preferred reporting items for systematic reviews and meta-analysis (PRISMA) flow diagram mapping the review\n \n\nPage 5 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nParticipants\nThe studies collectively included 579 women diagnosed \nwith POP , with participant ages ranging from 29.5 to \n67 years. Four of the eight studies specifically included \npostpartum women [ 5, 27, 28, 35]. The study popula -\ntions consisted of individuals with POP grades I, II, and \nIII; however, none of the studies examined the effects of \nPFMT on the morphological characteristics of women \nwith grade IV POP .\nPFMT characteristics\nThe duration of the PFMT interventions ranged from 5 \nweeks to 6 months. All studies incorporated three sets \nof daily PFMT, performed at or near maximal contrac -\ntion intensity. Adherence to the prescribed regimen was \nreported in five studies, all of which indicated high com -\npliance levels [5, 25, 26, 35, 36]. The most common train-\ning frequency was 8 to 12 voluntary contractions per set. \nIn six trials, the duration of each contraction hold ranged \nfrom 6 to 10 s [ 5, 25– 28, 34– 36], while three studies did \nnot specify the contraction hold duration [ 25, 26, 35]. \nThe rest interval between contractions ranged from 2 to \n10 s in four studies [5, 27, 28, 36].\nRegarding body positioning during PFMT, three stud -\nies instructed participants to perform exercises in lying, \nsitting, and standing positions [ 25, 26, 34]; one study \nallowed unrestricted positioning [ 5]; and four studies \ndid not report the participants’ exercise posture [ 28, 35, \n36]. PFMT was performed at home across all studies. All \nbut three studies [ 27, 28, 34] reported that participants \nreceived supervised sessions in combination with home \nexercise during at least some of the training sessions.\nIn five studies, PFMT was combined with additional \nconservative interventions such as the knack technique \n[25, 26], Hypopressive exercise [34], biofeedback, or elec-\ntrical stimulation [ 5, 27, 28], whereas in two studies [ 35, \n36] PFMT was performed as a standalone intervention. \nDetails of each of the included studies are in Table 1.\nMethodological quality\nThe risk of bias among the included studies is presented \nin Fig. 2. According to the PEDro scale, the methodologi-\ncal quality of the studies ranged from low to excellent. \nSpecifically, three studies were rated as excellent [ 25, 26, \n35], one as good [ 5], two as moderate [ 28, 34], and two \nas low quality [ 27, 36]. None of the studies implemented \nblinding of participants or therapists administering the \ninterventions. Assessor blinding was reported in three \nstudies [ 25, 26, 35]. All studies scored positively on the \nitems related to the specification of eligibility criteria and \nthe reporting of between-group statistical comparisons.\nOutcomes\nPrimary outcomes\nThe LHA during the rest position\nThree studies assessed the effects of PFMT on LHA at \nrest using transperineal ultrasound imaging [ 5, 27, 37]. \nThe pooled analysis of these studies demonstrated a sta -\ntistically significant reduction in LHA favoring PFMT, \nwith a mean difference (MD) of − 1.97 (95% CI: −2.79 to \n−1.15; p < 0.0001) (Fig. 3). Moderate heterogeneity was \nobserved among the studies (T² = 0.24; I² = 46.88%; p = \n0.166).\nThe LHA during the valsalva maneuver\nTwo studies evaluated the effects of PFMT on bladder \nneck position using transperineal ultrasound imaging \n[5, 27]. The meta-analysis of these studies demonstrated \na statistically significant reduction in LHA in favor of \nPFMT, with a MD of − 2.30 (95% CI: −3.36 to − 1.25; p \n< 0.0001) (Fig. 4). However, heterogeneity among the \nincluded studies was substantial (I² = 90.47%; p = 0.001).\nBladder neck position\nThree studies investigated the effects of PFMT on blad -\nder neck position using transperineal ultrasound imaging \n[25, 27, 35]. One RCT that was not included in the meta-\nanalysis due to insufficient data reported a significantly \ngreater cranial elevation of the bladder neck in the PFMT \ngroup compared to the control group [ 25]. Similarly, the \nmeta-analysis of two studies [ 27, 35] demonstrated a sig -\nnificant overall effect in favor of PFMT, with a MD of 0.16 \n(95% CI: 0.08 to 0.23, p < 0.0001) (Fig. 5). The heteroge-\nneity across the included studies was trivial (I² = 0.00%; p \n= 0.001).\nSecondary outcomes\nPOP stage\nFour studies evaluated the effects of PFMT on POP \nstage improvement, as defined by the Pelvic Organ Pro -\nlapse Quantification System (POP-Q). One RCT study \nreported a significantly higher proportion of women \nin the PFMT group who improved by one POP-Q stage \ncompared to the control group [ 25]. Two non-random -\nized clinical trials demonstrated significant improve -\nments in the POP stage following PFMT relative to \nbaseline [27, 36]. In contrast, one RCT found no signifi -\ncant difference in POP stage improvement between the \nPFMT and control groups [35].\nMeta-analysis was not feasible due to limitations in \ndata reporting across the included studies. One study \nreported outcomes using medians rather than means \n[36], one study did not provide numerical data [ 35], and \nthe other reported only the number of participants who \nimproved in each group [25].\n\nPage 6 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nReference Area Study \ndesign and \npopulation\nSamples number\n(mean age)\nIntervention description Outcomes Ultrasound \nimaging\ntechnique\nResults\nIntervention Control Inter-\nvention \n(duration)\nControl \n(duration)\n Braekken \net al. 2010 \n[25]\nNorway RCT (not \npostpartum)\n59 (49.4) 50 (48.3) The Knack + \nPFMT\n(3 sets of \n8–12 close \nto maximum \ncontraction, \ndaily for 6 \nmonths)\nThe knack\n(NR)\n-POP stage\n- Bladder \nand rectum \nposition\n-Symptoms\n- PFM \nstrength and \nendurance\nTransperineal The interven-\ntion group \nhad signifi-\ncantly better\nimprovement \nin all the \nmeasured out-\ncomes after\nintervention\n Braekken \net al. 2010 \n[26]\nNorway RCT (not \npostpartum)\n59 (49.4) 50 (48.3) The knack + \nPFMT\n(3 sets of \n8–12 close \nto maximum \ncontraction, \ndaily for 6 \nmonths) + \nbooklet\nThe knack\n(NR)\n- PFM \nstrength\n-Bladder \nand rectum \nposition\n-PFM \nthickness\n-LHA\nTransperineal The interven-\ntion group \nhad signifi-\ncantly better\nimprovement \nin all the \nmeasured out-\ncomes after\nintervention\n Bernardes \net al. 2012 \n[34]\nBrazil RCT (not \npostpartum)\nGroup I: 21 (51.9)\nGroup II: 21(56.7)\n16 (58.7) Group I: \nPFMT (3 sets \nof 8–12 close \nto maximum \ncontraction, \ndaily for 3 \nmonths)\nGroup II: \nPFMT (3–8 s \nPFMT) + Hy-\npopressive \nexercises (10 \nrepetitions, \ndaily for 3 \nmonths)\nThe knack (3 \nmonths)\n-Levator ani \nCSA\nTransperineal Both interven-\ntion groups \nhad signifi-\ncantly better \nimprovement \nin CSA of the \nlevator ani \nmuscle after \nintervention\nReference Area Study \ndesign and \npopulation\nSamples number\n(mean age)\nIntervention description  Outcome Ultrasound \nimaging\ntechnique\nResults\nIntervention Control Inter-\nvention \n(duration)\nControl \n(duration)\n Bø et al. \n2015 [35]\nNorway RCT \n(postpartum)\n87 (29.5) 88 (30.1) PFMT (3 sets \nof 8–12 close \nto maximum \ncontraction, \nweekly for 4 \nmonths)\nNo Exercise \nprescription\n-POP stage\n-Blad-\nder neck \nposition\n-POP \nsymptoms\n-PFM \nfunction\n-PFM \nstrength\nTransperineal The PFMT \nprogram did \nnot improve \nany of the \nmeasured \noutcomes, \nand there was \nno significant \ndifference \nbetween \ngroups after \nintervention\nTable 1 Details of included studies\n\nPage 7 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nReference Area Study \ndesign and \npopulation\nSamples number\n(mean age)\nIntervention description  Outcome Ultrasound \nimaging\ntechnique\nResults\nIntervention Control Inter-\nvention \n(duration)\nControl \n(duration)\n Ouchi et \nal. 2019 \n[36]\nJapan Clinical \ntrial (not \npostpartum)\n28 (67) - PFMT (10 \nseconds \nhold and \n10 seconds \nrelax, \nmaximum \ncontraction, \n3 sets daily \nat home and \n6 sessions \nsuper-\nvised for 4 \nmonths)\n- -POP stage Transperineal All measured \noutcomes \nwere \nimproved \nafter the \nintervention\nTakaoka al. \n2020 [5]\nJapan Clinical trial \n(postpartum)\n44 (31.1) 45(30.7) PFMT (6 \nsets of five \ncontrac-\ntions daily \nat home, \n6-8 seconds \nhold and \nrelax, last-\ning for 4 \nmonths), BF\nLeaflets \nabout \npostpartum \ninstructions\n-PFM \nstrength\nTransperineal The reduction \nin the LHA\nwas not \nstatistically \nhigher in the \nintervention \ngroup than \nthat in the \ncontrol group\nReference Area Study \ndesign and \npopulation\nSamples number\n(mean age)\nIntervention description  Outcome Ultrasound \nimaging\ntechnique\nResults\nIntervention Control Inter-\nvention \n(duration)\nControl \n(duration)\nYin et al. \n2022 [28]\nChina RCT \n(postpartum)\n30 (38.55) 30 (39.9) PFMT (7s \nhold and \nrelax, 10 \nminutes to \n15 minutes, \nand 3 to 8 \ntimes a day, \nlasting for \n8 weeks or \nmore, ES and \nBF (30 min-\nutes, 2 times \na week for \n10 sessions)\nGeneral \npostpartum \nguidance\n-LHA\n-PFM \nstrength\n-PFM \nthickness\nTransvaginal The interven-\ntion group \nhad signifi-\ncantly better\nimprovement \nin all the \nmeasured out-\ncomes after\nintervention\n Zhao et al. \n2024 [27]\nChina Clinical trial \n(postpartum)\n60 (31.02) - PFMT (6s \nhold and \n10-20s rest, \n10 to 15 \nrepetitions, 3 \ntimes a day \nfor 5 weeks), \nES and BF (2 \ntimes a week \nfor 5 weeks)\n- -POP stage\n-PFM \nstrength and \nactivity\n-PFM \nsensation\n-LHA\n-Blad-\nder neck \nposition\nTransperineal All measured \noutcomes \nwere \nimproved \nafter the \nintervention\nBF biofeedback, CSA cross-sectional area, ES electrical stimulation, NR no report, LHA levator hiatus area, PFM pelvic floor muscle, PFMT pelvic floor muscle training, \nPOP pelvic organ prolapse, RCT randomized controlled trial\nTable 1 (continued) \n\nPage 8 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nPFM strength\nFive studies assessed the effects of PFMT on PFM \nstrength using various outcome measures, including a \nvaginal balloon catheter [ 25, 35], manometer [ 36], the \nModified Oxford Scale [ 27], and, in one study, biofeed -\nback signal data [28].\nThe results of the RCTs demonstrated that partici -\npants in the PFMT group exhibited significantly greater \nimprovements in PFM strength and activity, as measured \nby any form of EMG, compared to the control group [ 25, \n28, 35].\nAdditionally, findings from clinical trials demonstrated \nthat PFM strength improved following the PFMT pro -\ngram compared to baseline measurements [ 27, 36]. A \nmeta-analysis was not performed due to the absence of \nessential data and the heterogeneity of outcome mea -\nsurement methods across studies.\nFig. 2 ( a) Risk of bias summary about each risk of bias domain for each included study separately. ( b) The overall risk of bias graph for included studies \nItems: (1) Eligibility criteria were specified, (2) Subjects were randomly allocated to groups (in a crossover study, subjects were randomly allocated an order \nin which treatments were received), (3) Allocation was concealed, (4) The groups were similar at baseline regarding the most important prognostic indica-\ntors, (5) There was blinding of all subjects, (6) There was blinding of all therapists who administered the therapy, (7) There was blinding of all assessors who \nmeasured at least one key outcome, (8) Measures of at least one key outcome were obtained from > 85% of the subjects initially allocated to groups, (9) \nAll subjects for whom outcome measures were available received the treatment or control condition as allocated or, where this was not the case, data for \nat least one key outcome were analyzed by intention to treat, (10) The results of between-group statistical comparisons are reported for at least one key \noutcome, 11. The study provides both point measures and measures of variability for at least one key outcome\n \n\nPage 9 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nDiscussion\nThis systematic review and meta-analysis evaluated the \neffects of PFMT on PFM morphometry in women with \nPOP . The results indicated that PFMT may improve \nPFM morphometric parameters, POP stage, and muscle \nstrength, particularly among women with stage I–III \nPOP . To our knowledge, this is the first meta-analysis \nspecifically investigating the effects of PFMT on PFM \nmorphometry in this population.\nThis systematic review and meta-analysis provides \nevidence supporting the efficacy of PFMT in reducing \nthe LHA both at rest and during the Valsalva maneu -\nver. These findings suggest that PFMT elicits measur -\nable morphological adaptations in the LHA, potentially \nFig. 5 Forest plot for the bladder neck position\n \nFig. 4 Forest plot for the levator hiatus area during the Valsalva maneuver\n \nFig. 3 Forest plot for the levator hiatus area during the rest position\n \n\nPage 10 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nindicative of PFM hypertrophy or architectural remodel -\ning in response to PFMT, particularly among postpartum \npopulations. These results align with a previous system -\natic review reporting favorable morphological changes \nfollowing PFMT in women with stress urinary inconti -\nnence and POP [ 17]. Collectively, these data suggest that \nPFMT may contribute to measurable reductions in LHA, \npotentially underscoring its clinical relevance in POP \nrehabilitation.\nIn addition, the findings suggest that PFMT may posi -\ntively influence bladder neck position in women with \nPOP , particularly those classified as stages I to III. This \npotentially supports the notion that PFMT could con -\ntribute to improvements in measurable morphological \nparameters, aligning with a previous report [ 17]. Mor -\nphological changes, such as reduced LHA and improved \nbladder neck position, may address core pathophysiologi-\ncal mechanisms underlying POP [38].\nWhile PFMT resulted in statistically significant changes \nin PFM morphometry, the clinical significance of these \nalterations is unclear. For example, the small elevation in \nbladder neck position observed in the present systematic \nreview and meta-analysis may reflect inherent ultrasound \nimaging measurement error, such as variability in probe \nplacement and operator technique [ 39], rather than a \ntrue morphological improvement. Moreover, although \nminimal clinically important differences (MCIDs) have \nbeen established for patient-reported outcomes in PFM \ndisorders [ 40], MCIDs for morphometric parameters \nremain undefined, which may limit clinical interpreta -\ntion. The predominance of women with POP stages I–III \nrestricts generalizability to more advanced cases. More -\nover, heterogeneity in PFMT protocols, imaging meth -\nods, and supervision intensity, along with the limited \nnumber and variable quality of included studies, weakens \nthe strength of evidence. Further high-quality RCTs with \nstandardized interventions and long-term follow-up are \nneeded to confirm these findings and determine optimal \ntraining parameters.\nEvidence on the improvement of the POP stage follow -\ning PFMT remains inconsistent. Most RCTs reported \nsignificant improvements [25, 27, 36], except one involv -\ning group-based PFMT without adjunct modalities [ 35]. \nPrograms incorporating supervision and additional tech -\nniques, such as biofeedback or electrical stimulation, \nappeared more effective in improving POP . Similarly, pre-\nvious systematic reviews have suggested that PFMT may \nimprove the POP stage [ 12, 13], supporting its potential \nas a conservative first-line therapy.\nThe present findings suggest that PFMT may enhance \nPFM strength, which in turn could contribute to \nimprovements in the POP stage [ 18]. Most included \nstudies consistently reported significant gains in PFM \nstrength following supervised PFMT [ 25, 27, 28, 35, 36], \nsupporting its role in reinforcing pelvic structural sup -\nport [ 41]. Intensive, individualized programs, as shown \nby Hagen et al., were also associated with reduced need \nfor surgical intervention [ 42]. Overall, these findings \nindicate that PFMT could serve as a first-line conserva -\ntive approach for POP , although further high-quality \nRCTs are required to confirm its efficacy and inform clin-\nical practice.\nThis systematic review and meta-analysis has some lim-\nitations. First, considerable heterogeneity across studies, \narising from differences in PFMT protocols (e.g., dura -\ntion, intensity, supervision, use of adjunct modalities) \nand imaging methods, may have affected pooled esti -\nmates. Second, most trials lacked long-term follow-up, \nlimiting insights into the sustainability of PFMT effects. \nFinally, the small number of high-quality RCTs and the \nabsence of participant and therapist blinding increase the \nrisk of bias.\nConclusion\nThis systematic review and meta-analysis suggest that \nPFMT may improve PFM morphology, POP stage, and \nmuscle strength among women with POP , particularly \nin stages I to III. Although evidence indicates possible \nmorphological improvements, such as reductions in LHA \nand improved bladder neck position, the limited number \nand variable quality of included studies warrant cautious \ninterpretation. The findings support the potential value of \nsupervised PFMT as a conservative management option \nfor POP; however, the heterogeneity of intervention pro -\ntocols highlights the need for further high-quality RCTs \nto confirm these results, establish their long-term clinical \nrelevance, and identify the patient subgroups most likely \nto benefit.\nAbbreviations\nCI  Confidence Intervals\nCINAHL  Cumulative Index to Nursing and Allied Health Literature\nLHA  Levator Hiatus Area\nMCIDs  Minimal Clinically Important Differences\nMD  Mean Difference\nMRI  Magnetic Resonance Imaging\nPEDro  Physiotherapy Evidence Database\nPFM  Pelvic Floor Muscle\nPFMT  Pelvic Floor Muscle Training\nPOP  Pelvic Organ Prolapse\nPOP-Q  Pelvic Organ Prolapse Quantification System\nPRISMA  Preferred Reporting Items for Systematic Reviews and \nMeta-Analyses\nRCTs  Randomized Controlled Trials\nREML  Random-Effects Model with the restricted maximum Likelihood\nSupplementary Information\nThe online version contains supplementary material available at  h t t p s :   /  / d o  i .  o r  \ng  /  1 0  . 1 1   8 6  / s 1 2  9 0 5 -  0 2 5 - 0  4 0 9 5 - 2.\nSupplementary Material 1.\n\nPage 11 of 12\nShahAli et al. BMC Women's Health          (2025) 25:542 \nAcknowledgements\nNot applicable.\nAuthors’ contributions\nSS: Concept development, literature searches, drafting, and revising the \nmanuscript. KB: Contributed to study design, manuscript preparation, and \nediting. AH: Contributed to study design, conducted statistical analyses, and \nassisted in manuscript preparation. HH: Contributed to study design and \nperformed data extraction. GK: Contributed to study design, performed data \nextraction, drafting, and revising the manuscript. All authors reviewed and \napproved the final version of the manuscript.\nFunding\nNot applicable.\nData availability\nThe datasets used and/or analysed during the current study are available from \nthe corresponding author on reasonable request.\nDeclarations\nEthics approval and consent to participate\nNot applicable.\nConsent for publication\nNot applicable.\nCompeting interests\nThe authors declare no competing interests.\nAuthor details\n1Iranian Center of Excellence in Physiotherapy, Rehabilitation Research \nCenter, Department of Physiotherapy, School of Rehabilitation Sciences, \nIran University of Medical Sciences, Tehran, Iran\n2Department of Sports Medicine, Norwegian School of Sport Sciences, \nOslo, Norway\n3Department of Physiology, School of Medicine, Iran University of Medical \nSciences, Tehran, Iran\nReceived: 1 September 2025 / Accepted: 10 October 2025\nReferences\n1. Haylen BT, Maher CF, Barber MD, Camargo S, Dandolu V, Digesu A, et al. 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