Introduction
Menopause is the stage in a woman’s life when her ovarian failure causes a variety of endocrine, physical, and emotional changes that affect the pelvic floor muscles (PFM) [1] and sexual function [2]. The pelvic floor tissue is affected by hormonal fluctuations in postmenopausal women, resulting in a shift of internal organs due to weakened supporting structures. Additionally, low estrogen levels can weaken the ligaments that support the pelvis and PFM, which could contribute to PFM weakness [3]. In addition, the drop in gonadal steroid hormone levels during menopause influences vaginal elasticity and secretion, leading to vaginal atrophy and dyspareunia, which are prevalent indicators of sexual dysfunction [4,5]. Furthermore, these hormonal fluctuations impede the process of filling the blood vessels of the vagina, leading to inadequate lubrication and arousal, a response induced by decreased blood circulation to the genital organs [6]. As a consequence, a decline in sexual quality is usually observed at this stage due to reported discomfort, mostly from pain, during sexual intercourse [7]. Unsatisfactory sexual relationships may cause feelings of inadequacy, anger, and insecurity [8]. The quality of life (QoL) after menopause can also be negatively affected by impairment in sexual function, which is one of the foremost health concerns for women following menopause [9].
Treatments targeting the PFM have been regarded as the benchmark for rehabilitating pelvic floor dysfunction in post-menopausal women by enhancing relaxation, strength, and endurance in the pelvic region [10] which could potentially lead to improved sexual function after menopause [11]. Recently, a new noninvasive approach using high-intensity focused electromagnetic therapy (HIFEMT) was introduced for the treatment of PFM [12,13]. In HIFEMT, an alternating magnetic field is used to induce involuntary contractions by transmitting them through the tissue. These contractions are classified as supramaximal contractions because they are more intense and repeated more frequently than voluntary contractions during PFM training. In addition, the induced contractions are deeper and more intense because the magnetic field passes through live tissues without attenuation [14,15]. Although the benefits of HIFEMT for PFM and sexual function have been proven in premenopausal [16] and parous women [14,15], no previous studies have explored the outcomes of HIFEMT in postmenopausal women. Therefore, this interventional study aimed to evaluate the relative benefits of HIFEMT on the PFM (primary outcome), sexual function, and QoL (secondary outcome) among postmenopausal women.
Materials and methods
This study followed the rules provided by the 2010 consolidated standards of reporting trials statement, which aims to standardize the reporting of studies using randomized control groups [17].
1. Study settings
This study, conducted from February 2023 to January 2024, employed a prospective, randomized, controlled design with a parallel-group, single-center focus. Women were sourced from the Obstetrics & Gynecology Outpatient Clinic at Almahalla General Hospital in Egypt with referrals enabled by gynecologists. The interventions were conducted in the hospital’s physical therapy department.
2. Sample size estimation
The ideal participant count for each group was determined using G Power 3.1 (Heinrich Heine University, Düsseldorf, Germany). This computation was based on a research by Dudonienė et al. [18], utilizing the PFM strength on perineometry for calculation. A two-sided t-test with a 5% chance of error (α), 85% power, and an effect size of 0.43 were all included in the computations, which resulted in an estimated sample size of 21 participants in each group. Nevertheless, 25 women were selected as the sample for each group to make the results more reliable and reduce any possible attrition effects.
3. Randomization and allocation
This study employed simple randomization. The sample of women (n=50) was successfully assigned to groups using a strict randomization process produced by SPSS computer software for Windows, version 22 (SPSS, Inc., Chicago, IL, USA). Randomization was performed by a physiotherapist who was not involved in the recruitment, data collection, or intervention of the study. The randomization codes were concealed in sequentially numbered opaque envelopes from 1 to 50 to ensure allocation concealment. Another physiotherapist, not involved in the study, opened the envelopes in that order, and the women were randomly selected from one of the two intervention or control groups. Achieving an equal distribution of the control and study groups using an identical allocation ratio (1:1) reduced the possibility of selection bias.
4. Blinding
The recruiters, two physiotherapists who were not involved in the study, were blinded to the women’s allocation groups throughout the whole recruiting process. Due to the basic nature of the therapeutic regimen used, it was not possible to blind the participating women or HIFEMT supervisors. In contrast, the PFM exercise supervisors were blinded. In addition, all outcome measure evaluations for both groups were conducted before and after treatment completion by two physiotherapists blinded to the women’s group allocation to minimize bias. Additionally, the assessors did not participate in any intervention.
5. Participants
The study included 50 postmenopausal married women with a maximum age of 5 years since menopause. All women had mild to moderate PFM weakness with manometry scoring 14.6 to 41.5 cmH2O [19] in addition to mild to moderate sexual dysfunction scoring 14.5 to 21.6 on the female sexual function index (FSFI) [20]. All women had regular sexual intercourse with penile penetration of the vagina. Participants were aged between 45 and 60 years and had a body mass index (BMI) of <30 kg/m2. They were multiparous with normal vaginal delivery. The exclusion criteria were women with prolapse of the pelvic organs, pelvic tumors, vaginal infections, metal implants, blood coagulation disorders, diabetes mellitus, any other contraindications to HIFEMT, and those who refused to complete the self-report questionnaires.
The participating women were allocated to two equal groups with no discrimination: the HIFEMT (PFM training in addition to HIFEMT) and the control (PFM training only) groups. Fig. 1 comprehensively depicts the progressive development of the women over the course of the trial.
6. Evaluations
1) History and clinical assessment
The suitability of women to participate in the trial was ascertained by a specialized gynecologist through comprehensive clinical examinations and medical history evaluations. Demographic, anthropometric, and clinical data were recorded for each participant. At the outset, the height and body weight of the participants were evaluated using a computerized scale designed for measuring weight and height (BYH01, Zhejiang, China). Using a standardized formula, BMI was calculated by dividing weight in kilograms by the square of height in meters [21].
2) PFM measures (primary outcome)
Both PFM strength and endurance were measured using a MizCure perineometer (OWOMED, Seoul, Korea) composed of a vaginal balloon filled with air measuring 75 mm in length and 28 mm in diameter. The balloon is coupled to a pressure transducer. Perineometry is an easy, minimally invasive, cost-effective, and reliable tool for the PFM [22]. The female participants underwent testing while lying on their backs with their knees bent and legs slightly apart. They were instructed to contract their PFM without moving their pelvis or contracting their gluteal, hip, or abdominal muscles visibly. Each woman contracted her PFM to a maximum without holding her breath and rested for fives between attempts thrice. PFM strength was defined as the mean of three maximum voluntary contractions (mmHg). PFM endurance was determined by calculating the mean duration of three endurance trials measured in seconds. The women were instructed to maintain sustained maximum voluntary contraction of the PFM without inhalation for as long as possible. The trial was terminated when the squeezing pressure decreased by 2 mm. A 10-second interval was permitted between each of the three trials [23]. Strength and endurance of the PFM were evaluated at baseline and after 12 weeks.
3) Sexual function (secondary outcome)
The current study used the Arabic version which proved validated by Anis et al. [24] to evaluate the sexual function at the beginning and 12 weeks later for all women via inperson interviews. The FSFI consists of 19 items that allow women to self-report sexual function. It evaluates numerous facets of sexual function, including sexual desire, arousal, orgasm, pain, and satisfaction and offers scores for each component as well as an overall score for sexual function. The 19 items of the FSFI are rated on a 5-point Likert scale ranging from 1 to 5, with higher scores for each item indicating better levels of sexual function [25]. Sexual dysfunction was characterized by a total score of 26.5 or below on FSFI [26].
4) QoL (secondary outcome)
The Arabic version of the menopause-specific quality of life questionnaire (MENQOL) was used to evaluate the QoL of postmenopausal women in both groups. This Arabic version was validated and translated by Smail et al. [27] from the original English one. MENQOL consists of 29 items categorized into four domains: vasomotor, psychosocial, physical, and sexual. Items related to a particular symptom were evaluated as either present or absent, and if present, the level of annoyance was assessed on a scale of zero (indicating no bothersomeness) to six (indicating extreme bothersomeness). An item receives a score of “1” if it is not endorsed and a score of “2” if it is endorsed, in addition to the specific rating number. Therefore, the potential score for each item may vary from 1 to 8. The domain score was the mean of the domain item scores, with higher scores indicating a greater degree of QoL disruption. The overall MENQOL score was calculated using the mean of all four domains [28]. Patients were given the MENQOL via in-person interviews both at baseline and 12 weeks later.
7. Interventions
1) PFM training
All participants, regardless of their assigned group, participated in the PFM training. Thirty minutes of initial therapist-supervised instruction on how to contract the PFM comprised the PFM training. The participants were directed to gradually execute three sets of eight to twelve maximal voluntary floor contractions, with a 6-second pause between each contraction. All contractions were executed on the mat, in a supine position with the legs bent and relaxed. Supervised PFM exercises were performed twice weekly for 12 weeks [29]. Two qualified physiotherapists who were not engaged in the evaluations monitored the exercise sessions throughout the research period. Each participant was instructed to perform their own exercise regimen as a home routine on alternate days. The level of compliance with PFM training was continuously monitored. Each woman maintained an exercise table during the 12-week intervention, recording the specific dates and times of their workouts.
2) HIFEMT
For 12 weeks, the women assigned to the HIFEMT group received two sessions each week using the BTL EMSELLA chair device (BTL Industries Inc., Boston, MA, USA). It was equipped with a power generator and a circular coil positioned in the seat of the chair. The EMSELLA chair device utilizes HIFEMT to strengthen PFM. Based on the manufacturer’s instructions, the women undergoing treatment were instructed to remain fully dressed and placed in the middle of the chair. They were asked to tilt their pelvic region towards the center while applying alternating magnetic fields. The intensity of the magnetic fields started at a low level, as reported by the women, and subsequently increased to 2.5 tesla. Each woman received 24 HIFEMT treatments during the course of the research period.
8. Analysis of data
Statistical analyses were performed using SPSS for Windows version 22 (SPSS, Inc.) to analyze the data and check for outliers and the normalcy assumption before completing the analysis. The results of the Shapiro-Wilk test showed that the data followed a normal distribution (P>0.05). Standard deviation, mean, and paired and unpaired t-tests were used for statistical analysis of the data that was obtained. A paired t-test was used to compare variables within the same group. An unpaired t-test was used to compare the groups. Categorical variables were compared using the chi-squared test. All statistical tests were performed at a significance of 0.05.
Results
Throughout the trial, no side effects secondary to the HI- FEMT or PFM training were reported. Of the 50 women, three were lost to the HIFEMT group and four were lost to the control group based on their request to withdraw. When comparing the two groups’ adherence to the treatment sessions, no significant differences were detected (P>0.05) (Table 1).
2. Post-intervention within groups
Compared to the initial measures, the PFM results, comprising strength and endurance, showed substantial improvements in both the HIFEMT and control groups (P<0.05) (Table 2). Additionally, subgroup analyses based on the levels of PFM weakness (mild and moderate) revealed significant improvements in the PFM strength and endurance for both weakness levels within both groups (P<0.05) (Table 4). In each group, there was a significant increase (P<0.05) in the total FSFI and its six components, including desire, arousal, lubrication, orgasm, satisfaction, and pain (Table 3). Additionally, subgroup analyses based on the degree of sexual dysfunction (mild and moderate) revealed significant increases in the FSFI scores at both levels of sexual dysfunction in both groups (P<0.05) (Table 4). Furthermore, the study found substantial declines in all four domains and overall MENQOL scores of MENQOL (P<0.05) (Table 5).
3. Post-intervention between groups
Compared to the controls, the HIFEMT group demonstrated more significant improvements in the PFM strength (mean difference [MD], 9.99 vs. 5.29 cmH2O; P=0.001) and endurance (MD, 7.1 vs. 6.01; P=0.005) upon the completion of the trial (Table 2).
Regarding the FSFI scores, the HIFEMT group, in comparison with the control one, revealed more significant enhancements in desire (MD, 1.2 vs. 0.4; P=0.02), arousal (MD, 1.04 vs. 0.44; P=0.02), lubrication (MD, 1.36 vs. 0.68; P=0.008), orgasm (MD, 1.12 vs. 0.64; P=0.04), satisfaction (MD, 1.04 vs. 0.32; P=0.01), pain (MD, 1.56 vs. 0.92; P=0.01) and the total score (MD, 7.96 vs. 5.0; P=0.01) post-intervention (Table 3).
In favor of the HIFEMT group, the MENQOL revealed more significant declines in the vasomotor (MD, −1.42 vs. −0.65; P=0.03), psychosocial (MD, −1.66 vs. −1.13; P=0.04), and sexual (MD, −2.0 vs. −1.02; P=0.04) domains, in addition to the overall mean score (MD, −1.51 vs. −0.9; P=0.01) when compared to those in the control group post-intervention (Table 5). However, the post-intervention physical domain scores showed no significant difference between the HIFEMT and control groups (MD, −0.94 vs. −0.77; P=0.17) (Table 5).
Discussion
As far as we are aware, our research is the first to explore the effect of HIFEMT, in combination with PFM training, on measures of the PFM strength and endurance, sexual function, and QoL, compared to the effect of PFM training, in isolation, in postmenopausal women.
The study found that 12 weeks of PFM training alone or in combination with HIFEMT produced significant improvements in the PFM strength, endurance, sexual function, and QoL compared to the baseline data. In addition, adding HI- FEMT to PFM training resulted in greater improvements in all outcome measures than PFM training alone in such women.
These improvements following HIFEMT may be explained by an understanding of its beneficial physiological effects. The magnetic field produced during HIFEMT leads to excitation of the pelvic floor nerves, resulting in PFM contractions [14], similar to PFM exercises. However, because HIFEMT is supraphysiological, it may activate muscles faster and more intensively than traditional PFM training can [15]. HIFEMT-induced contractions may be accomplished at great depths and intensities because the magnetic field can travel through any medium without energy attenuation [30]. In addition, increased PFM strength and endurance are associated with beneficial morphological changes in the muscle tissue after HIFEMT [15,31]. Using ultrasonography to track changes in muscle thickness, Samuels et al. [31] found a +24.2% increase 3 months after HIFEMT. In addition, pelvic floor dynamics improved after 10 HIFEMT treatments according to three-dimensional ultrasounds, which revealed smaller anteroposterior and laterolateral diameters and hiatal areas [15]. Additionally, PFM electromyography measurements (maximal voluntary contraction), as an indicator of functionality, improved significantly in postpartum women with pelvic floor dysfunction following 10 sessions of HIFEMT, relative to the control and baseline [14]. An additional important advantage of the non-invasive HIFEMT procedure is its significant therapeutic safety achieved while strengthening PFM across a broad range of patients when compared to other available invasive treatment options [12].
Similar to our findings, HIFEMT in women with urinary incontinence resulted in significant improvements in strength and endurance measurements of the PFM, assessed using perinometry, following a single-session intervention [32] and after 12 sessions [18]. In men with premature ejaculation, 28 minutes of weekly pelvic floor HIFEMT for 4 weeks was sufficient to increase the PFM strength compared to that at baseline [33].
Another important finding of the current study was the improvement in sexual quality seen in the HIFEMT group when compared to both the baseline and control groups. Low estrogen levels after menopause can result in less sexual responsiveness as poor vaginal lubrication can result in dyspareunia and, consequently, have an impact on the decrease of sexual desire [34]. Strengthening the PFM is the first strategy to improve the female sexual function [35]. Promoting PFM strength increases muscle awareness and proprioception, improves muscle relaxation, restores normal PFM activity, and increases the elasticity of the tissues, which can help reduce sexual pain in women [36]. In addition, stronger PFM respond to sexual triggers by increasing blood flow to the area, and therefore, provide more effective lubrication during intercourse [37]. Therefore, an improvement in women’s sexual desire is usually expected after pelvic floor strengthening [38]. The added strengthening effect of HIFEMT can explain the achieved improvements, mainly in sexual desire, lubrication, and pain (P=0.02, 0.008, and 0.01; respectively), when compared to the control group.
Similar to our results, 30 women with impeded sexual functioning showed noticeable improvements in sexual performance throughout the six sections of the FSFI following six sessions of HIFEMT, each lasting 28 minutes with sessions planned twice a week [16]. In addition, postmenopausal women with urinary incontinence and female sexual dysfunction symptoms responded significantly to six HIFEMT sessions for a total of 3 weeks, twice weekly, by reporting enhanced lubrication, more frequent orgasms, and heightened desire [13].
As a consequence of improvements in PFM and sexual function, QoL improvements in the HIFEMT group were more significant than those in the control group. Both the physical and emotional well-being of a woman depend on her ability to have normal sexual function, and any abnormalities in these functions may lead to emotional and interpersonal communication challenges in addition to experiencing more intense menopausal symptoms that might affect the QoL of postmenopausal women [11]. Therefore, optimal sexual function enhances health status while promoting a good QoL [39]. Similar to our results, following six HIFEMT sessions, postmenopausal women with urinary incontinence showed marked improvements in self-reported changes in QoL [12] and improvements in the QoL King’s Health Questionnaire [40].
This study has several benefits. This investigation was groundbreaking regarding health issues after menopause. Notably, this study is the first to directly investigate the efficacy of HIFEMT on PFM, sexual quality, and QoL in post-menopausal women. Nevertheless, as in several other studies, it is important to evaluate these findings while considering certain limitations. One such constraint was the shyness of some women who completed the FSFI and the PFM testing procedure, which could have affected the outcome measures. In addition, the comparatively short 12-week follow-up period is a major limitation of this study. Moreover, psychosocial variables or life stress may also have impacted the QoL assessment; however, this was outside the control of the researchers conducting this study.
These findings highlight the potential benefits of HIFEMT as a noninvasive and low-risk supplementary strategy for managing PFM weakness, sexual dysfunction, and impaired QoL in post-menopausal women. However, conducting more randomized studies with larger groups of participants and longer follow-up periods are recommended in order to confirm and reinforce these results.
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