Transperineal Ultrasound as a Biofeedback Tool for Pelvic Floor Muscle Therapy in Postpartum Patients
Phase: NA
Conditions: Pelvic Floor Muscle Training, Transperineal Ultrasound, Biofeedback Therapy, Postpartum, Pelvic Floor Disorder, Pelvic Floor Muscle Exercise, Pelvic Floor, Obstetric, Pelvic Floor Dysfunction, Pelvic Floor Health After Childbirth, Physiotherapy, Physiotherapy Specialty
Sponsor: Singapore General Hospital

 
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RESEARCH STUDY PROTOCOL 
 
 
PROTOCOL TITLE: 
Transperineal ultrasound as a biofeedback tool for pelvic floor muscle 
therapy in postpartum patients. 
 
 
 
 
 
 
 
 
PROTOCOL NUMBER: 
1 
 
 
 
 
 
 
 
 
 
VERSION NUMBER: 
4 
 
 
 
 
 
 
 
 
 
VERSION DATE:  
25th March 2025 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
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1 Table of Contents 
1 
BACKGROUND AND RATIONALE ............................................................................................. 3 
2 
HYPOTHESIS AND OBJECTIVES.............................................................................................. 3 
3 
EXPECTED RISKS AND BENEFITS ........................................................................................... 4 
4 
STUDY POPULATION .............................................................................................................. 4 
4.1 
LIST THE NUMBER AND NATURE OF SUBJECTS TO BE ENROLLED. ................................................................................. 4 
4.2 
CRITERIA FOR RECRUITMENT AND RECRUITMENT PROCESS ....................................................................................... 4 
4.3 
INCLUSION CRITERIA ................................................................................................................................................ 5 
4.4 
EXCLUSION CRITERIA ............................................................................................................................................... 5 
5 
STUDY DESIGN AND PROCEDURES/METHODOLOGY .............................................................. 5 
5.1 
METHODOLOGY ........................................................................................................................................................ 5 
5.2 
CONSORT FLOW DIAGRAM ..................................................................................................................................... 9 
5.3 
STATISTICAL ANALYSIS ........................................................................................................................................... 10 
6 
SAFETY MEASUREMENTS ..................................................................................................... 10 
6.1 
DEFINITIONS .......................................................................................................................................................... 10 
6.2 
COLLECTING, RECORDING AND REPORTING OF SERIOUS ADVERSE EVENTS (SAES) TO CIRB .................................. 10 
6.3 
DATA SAFETY MONITORING PLAN ........................................................................................................................... 10 
6.4 
COMPLAINT HANDLING ........................................................................................................................................... 11 
7 
DATA ANALYSIS................................................................................................................... 11 
7.1 
DATA QUALITY ASSURANCE .................................................................................................................................... 11 
7.2 
DATA ENTRY AND STORAGE .................................................................................................................................... 11 
8 
SAMPLE SIZE AND STATISTICAL METHODS ......................................................................... 12 
8.1 
DETERMINATION OF SAMPLE SIZE ........................................................................................................................... 12 
8.2 
STATISTICAL AND ANALYTICAL PLANS ..................................................................................................................... 12 
9 
DIRECT ACCESS TO SOURCE DATA/DOCUMENTS ................................................................. 12 
10 
QUALITY CONTROL AND QUALITY ASSURANCE ................................................................... 12 
11 
ETHICAL CONSIDERATIONS ................................................................................................ 13 
11.1 
INFORMED CONSENT .............................................................................................................................................. 13 
11.2 
CONFIDENTIALITY OF DATA AND PATIENT RECORDS ............................................................................................... 13 
12 
PUBLICATIONS .................................................................................................................... 13 
13 
RETENTION OF STUDY DOCUMENTS .................................................................................... 13 
14 
FUNDING AND INSURANCE ................................................................................................. 13 
15 
REFERENCES ....................................................................................................................... 14 

 
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1 
BACKGROUND AND RATIONALE 
Pelvic floor exercises (PFE) form the basis of recovery of the pelvic floor musculature after vaginal birth. 
Regular and effective PFE training has been demonstrated to reduce the risk of common pelvic floor 
disorders such as urinary and fecal incontinence, pelvic organ prolapse and sexual dysfunction[1]. However, 
in the postpartum period, effective pelvic floor muscle therapy is often overlooked with only 20% of 
postpartum women performing PFE on a regular basis[2]. One-on-one, supervised pelvic floor therapy with 
a trained physiotherapist can improve adherence to PFE. However, even when this group of women are 
evaluated, only 27% of them perform PFE in an effective manner[3].  
 
The reasons for the poor adherence and effectiveness of PFE are multi-factorial. Lack of awareness of how 
to engage the pelvic floor muscles as well as what constitutes an effective contraction are the main barriers 
for effective therapy. A trained physiotherapist can make a digital assessment of pelvic floor muscle tone, 
however this assessment only provides indirect feedback to the patient. Verbal cues are often the only means 
of training and refining a patient’s technique with PFE. What is needed is an objective, visual training tool 
that is available for evaluation by both physiotherapist and patient. 
 
Biofeedback is the process by which a patient is able to control, train and modify voluntary body functions 
with aid of sensory feedback tools for the purpose of improving health and wellbeing[4]. Various biofeedback 
tools exist in medicine but in the context of pelvic floor physiotherapy, the use of transperineal ultrasound 
(TPUS) has gained popularity over the years due to its ability to clearly demonstrate the pelvic floor muscles 
and their interactions (Fig. 1). TPUS has the advantage of being accessible, safe, easy to use and relatively 
non-invasive compared to other imaging modalities. It can be utilized in the outpatient (clinic) setting, 
providing real-time visualization of the pelvic floor and does not expose patient to potentially harmful 
ionizing radiation. Where available, many departments choose to utilize TPUS as an adjunct to pelvic floor 
muscle training. However, to date, no data exists which evaluates its effectiveness as a biofeedback tool in 
postpartum women. The primary aim of this study is to assess, under controlled conditions, whether the 
additional use of TPUS can serve as a useful biofeedback tool for postpartum patients during pelvic floor 
muscle therapy. 
 
 
Figure 1: 2D mid-sagittal image of the pelvic floor at rest (Left) with corresponding anatomical overlay (Right). SP - symphysis pubis, U - 
urethra, P - perineum, LA - levator ani (puborectalis muscle). 
 
2 
HYPOTHESIS AND OBJECTIVES 
Null hypothesis – transperineal ultrasound is not an effective biofeedback tool during pelvic floor muscle 
therapy. 
Alternate hypothesis – transperineal ultrasound is an effective biofeedback tool during pelvic floor muscle 
therapy. 
 

 
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Primary outcome 
Does visual feedback with transperineal ultrasound improve the effectiveness of pelvic floor muscle therapy 
in postpartum patients? 
 
Secondary outcomes 
a. Are postpartum patients who have trained with visual biofeedback more likely to continue to perform 
pelvic floor muscle therapy than those who do not train with visual biofeedback? 
b. Do postpartum patients who train with visual biofeedback continue to perform effective pelvic floor 
muscle contractions 3 months after pelvic floor muscle training. 
c. Does pelvic floor contraction strength improve after 3 months of pelvic floor muscle therapy with visual 
biofeedback compared to those who did not receive visual biofeedback.  
 
3 
EXPECTED RISKS AND BENEFITS 
The only intervention performed in this study is the addition of transperineal ultrasound (TPUS). 
Ultrasonography is the use of high frequency sound waves to create an image of underlying structures. It has 
been utilized for decades and provides detailed images used for diagnostic purposes. It is extremely safe as 
it does not involve the use of ionizing radiation. Some data suggest that high energy ultrasound (which will 
not be used in this study) may produce heat effects of human tissue, however these effects have no known 
consequences on fetal nor maternal health[7]. This study intends to recruit postpartum (and therefore, non-
pregnant) women therefore what little potential risk there is, is substantially reduced in this study population. 
Transperineal ultrasound has a similar safety profile to all other ultrasound-based imaging modalities with no 
reported adverse effects from its use [8]. Overall, despite the excellent safety profile this study will continue 
to use ultrasound at the lowest required energy setting for the minimum amount of time. 
 
The major benefit of this study is that it can potentially introduce a tool to objectively measure the 
effectiveness of pelvic floor muscle contractions. This can be beneficial both to the patient and the clinician 
who is treating them. Patients will be able to use visual cues to help train and refine their technique resulting 
in better outcomes. Clinicians can offer bespoke guidance to aid recovery and prevent progression of pelvic 
floor disorders. For future clinicians it can also be used as a training tool and can help remove subjectivity 
and therefore the potential for error from clinical practice. 
 
4 
STUDY POPULATION 
 
4.1 List the number and nature of subjects to be enrolled.  
This study is a single-site, prospective randomized controlled trial of female postpartum patients attending a 
specialized pelvic floor assessment clinic. Sample size calculations estimate that a total number of 94 
participants are required (47 in each arm) to demonstrate a difference between the study group and the 
control group and therefore reject the null hypothesis (see Section 8.1).   
 
4.2 Criteria for Recruitment and Recruitment Process 
Recruitment of potential participants will occur in the outpatient setting. Postpartum patients attending the 
specialized pelvic floor assessment clinic will be screened, and if they meet the eligibility criteria will be 
offered an opportunity to participate. Participation in the study will be voluntary and go alongside the 
patient’s normal clinical care. Informed, written consent will be obtained and each of the participants will 
have the right to withdraw from the study at any point.  
 

 
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4.3 Inclusion Criteria 
• Female participants 
• Aged 21 – 45 years old. 
• Within 4 months of a singleton, vaginal delivery. 
 
4.4 Exclusion Criteria 
• Currently pregnant 
• Over 4 months since vaginal birth. 
• Previous caesarean delivery. 
• Previous pelvic floor surgery (eg. pelvic floor repair, continence surgery, cervicetomy, cosmetic 
pelvic floor procedures)  
• Neurological disorder affecting muscle contraction (eg. Guillan-Barre syndrome, motor neuron 
disease, multiple sclerosis) 
 
5 
STUDY DESIGN AND PROCEDURES/METHODOLOGY 
 
5.1 Methodology 
 
This is a prospective, randomised controlled study and will be conducted through five stages: 
 
 
Stage 1: Recruitment and randomisation. 
 
Stage 2: Assessment. 
 
Stage 3: Preliminary analysis and Interim report. 
 
Stage 4: Follow up assessment. 
 
Stage 5: Final analysis.  
 
5.1.1  Stage 1: Recruitment and Randomisation 
Postpartum patients who attend the pelvic floor assessment clinic will be screened for eligibility to the study. 
The study team will be responsible for screening and recruiting the participants based on the aforementioned 
inclusion/exclusion criteria. If eligible, the potential participant will be approached by a member of the study 
team and provided with a Participant Information Sheet and Consent Form. If they agree, they will be 
recruited to the study and will be allocated a study identifier number (SIN). A member of the study team will 
take written consent from the participant. English will be the default language of use; however, interpretation 
will be available in both Chinese, Malay and Tamil if required. Each participant will be asked to complete the 
pre-study questionnaire. Participants will be randomized into two different arms for the study (control arm 
and study arm). Equal numbers are required in each arm and therefore randomization will be performed 
using a computer randomizer set to distribute SINs into two equal groups.   
 
5.1.2 
Stage 2: Assessment  
Assessment of participants is divided into two parts. The first part involves the gathering of clinical data such 
as demographic, pregnancy, and symptom information. This is obtained through their electronic medical 
record (using only the Citrix application), as well as eliciting symptoms history verbally from the participant. 
A clinical examination for uterovaginal prolapse is performed and a digital examination to assess pelvic floor 
muscle tone, known as the Modified Oxford Scale (MOS), is recorded in the standing position[5]. This 
assessment forms part of the usual care for each of the participants and can therefore be performed by any 
qualified member of their clinical care team. After this assessment, study participants are provided with a 

 
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specially designed hard-copy questionnaire to complete which is relevant to the aims of the study. This is to 
ascertain the participants knowledge of, and exposure to pelvic floor muscle therapy. 
 
The second part of the assessment is conducted by a member of the study team specialized in transperineal 
ultrasound of the pelvic floor and pelvic floor muscle training techniques. Each participant is asked to 
undress from the waist down and lay supine for the examination. A chaperone is present and dignity is 
maintained throughout.  
 
Participants will be encouraged to “squeeze the muscles” of their perineum and several attempts will be given 
to each participant to achieve this. Verbal feedback will be given by the assessor after each attempt to be 
sure the participant is activating their pelvic floor muscles and not co-activating their abdominal or gluteal 
muscles.    
 
Transperineal ultrasound is then performed for all participants. Preparation of the probe involves applying 
a single-use, non-latex probe cover around a GE™ RAB2-5-MHz 3-dimensional volume transducer with 
generous amounts of ultrasound conducting gel placed inside and outside the probe cover. The transducer 
is placed upon the participant’s perineum, in the mid-sagittal plane, and acquisition of images in conducted 
through a Voluson™ S10 ultrasound system. An acquisition angle of 85° is set and the machine is configured 
to the “Pelvic Floor” setting.  
 
Participants in the control arm will have the ultrasound screen turned away from them with only the assessor 
having access to it. One 3d static image of the pelvic floor at rest will be obtained. The assessor will then ask 
the participant to perform a pelvic floor muscle contraction where a 4d dynamic image of the pelvic floor 
will be obtained. Three attempts at pelvic floor muscle contraction will be made for each participant. During 
this time the assessor will provide no feedback nor encouragement to the participant.  
 
Participants in the study arm will have the ultrasound screen turned towards them in a way that both the 
assessor and participant can view it. A simple demonstration of the pelvic anatomy will be given to the 
participant outlining the orientation of the image as well as the basic pelvic structures such as positions of 
the bladder, vagina and rectum. As in the control group, the assessor will obtain the same static 3d image of 
the pelvic floor at rest as well as three dynamic 4d images during a pelvic floor contraction. Unlike the control 
group, the participant will be able to visualize in real-time the dynamic movement of their pelvic floor. They 
will be permitted to adjust/strengthen their technique between attempts based on these visual cues.  
 
Upon completion of the assessment, all participants will have a follow up visit arranged in 3 months. This 
appointment usually forms a standard part of their clinical care and will be utilized to perform the follow up 
assessment. Participants who wish to continue to take part in the study will be informed that they will have 
the opportunity to repeat the assessment again during their follow up visit and will be encouraged to continue 
to perform pelvic floor muscle therapy in the interim. 
 
5.1.3 
Stage 3: Preliminary analysis and Interim report 
This stage is performed by the study team only and does not require the involvement of the participants. 
Ultrasound data sets will be evaluated by a member of the study team who is blinded to the clinical data as 
well as to the study arm that the data set belongs to. The following describes the measurement parameters 
which are relevant to the study. 
 
a. Antero-posterior (AP) pelvic hiatal diameter. 

 
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This is defined as the distance between the inferior edge of the symphysis pubis and the greatest 
apogee of the puborectalis muscle. The measurement can be obtained in both the mid-sagittal as well 
as the transverse (axial) planes (Fig. 2). However, care must be taken to orientate the 3d/4d image to 
reflect the correct plane of viewing regardless of the method of measurement.  
 
It is well established that the AP hiatal diameter is a very good indicator of pelvic floor muscle 
contraction. Based on a previous study, a proportional change in AP hiatal diameter of >15% 
corresponds well with a normal pelvic floor muscle contraction[6]. This cut-off value will be utilized 
to determine the adequacy of contraction.  
 
b. Transverse diameter 
This is defined as the maximal diameter between the inner edge of the levator ani muscles and is 
measured solely in the transverse plane. As with AP diameter, changes in transverse diameter are 
associated with effective muscle contractions, albeit to a lesser extent[6]. The transverse diameter can 
be a useful adjunct to the AP diameter as it provides assurance that that a pelvic floor contraction is 
effective.  
 
c. Pelvic hiatal area 
This is the defined as the area enclosed anteriorly by the symphysis pubis, laterally by the levator ani 
and posteriorly by the puborectalis. This measurement can only be obtained in the transverse plane 
and conventionally measured along the axis subtended by the symphysis pubis and greatest apogee 
of the puborectalis. 
 
Changes in the pelvic hiatal area correspond well with clinical assessments, such as use of the MOS[6]. 
Care will be taken to ensure the correct plane is measured during rest and contraction and 
measurement of the area will be performed by tracing the inner outline using the trace function on 
the Voluson™ S10 ultrasound system. 
 
Figure 2: Pelvic hiatal measurements taken in the resting state along the transverse (axial) plane. Anteroposterior diameter (1), Transverse 
diameter (2). Right image - Genital hiatal area (1).  

 
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Preliminary analysis will be performed when the minimal sample size has been reached. Results of the analysis 
will form the basis of the studies’ interim report. The interim report will ultimately aim to answer the primary 
hypothesis of the study- to determine if a significant difference is observed in pelvic floor muscle contraction 
between the study group and the control group. However, prior to this, several quality assurance checks will 
be performed. These quality assurance measures are described later (Section 7.1). 
 
The interim report will also explore if there were any issues/adverse effects of the study and if so, whether 
this would warrant discontinuation of the trial. We do not anticipate any adverse physical effects of the study 
as the use of ultrasound is very safe. However, we do anticipate that some patients within the control group 
may wish to visualize their pelvic floor anatomy on ultrasound. As this would compromise the validity of the 
next stage of the study, we would be required to withdraw the participant from the study at this stage if they 
were to request this. We would be able to grant this request willingly at the end of the next stage as 
visualization after Stage 4 is complete will not compromise the results of the study.  
 
5.1.4  Stage 4: Follow up assessment 
This stage will occur 3 months after the initial assessment stage. Participants enrolled in the study will be 
invited back for a follow up review consisting of an assessment of any symptoms, adherence to PFMT and 
repeat ultrasound assessment of their pelvic floor muscle strength. As previously mentioned, the follow up 
stage is part of the standard clinical care for each patient and therefore the study will be done in parallel with 
their usual clinical care. 
  
A similar method of assessment will be employed to the initial assessment, where a physical examination for 
uterovaginal prolapse and MOS grading are conducted. TPUS assessment will be done at rest, but when 
performing a pelvic floor muscle contraction, all participants will be blinded from visual biofeedback. Only 
the assessor will have access to the ultrasound screen and no verbal feedback or encouragement will be given 
during this time. As with the initial assessment three attempts at pelvic floor muscle contraction will be given 
to each participant with the best one being used for final analysis. The assessors themselves will be blinded 
to clinical data as well as the results of the previous assessment. Data will continue to be de-identified, using 
only the SIN as a reference to data sets. 
 
The follow up will also be an opportunity to address any adverse effects or difficulties each participant may 
have experienced since the initial assessment. These will be thoroughly documented as part of the study 
results and will be managed appropriately by their clinical care team. The CIRB will be informed of any 
adverse event the participant suffers as a result of their participation in the study. Participant involvement 
will end at this stage. If requested, participants in the control arm, may view the images of the pelvic floor at 
rest and during contraction. Advice will be given to them on how to manage their pelvic floor symptoms 
and an opportunity for questions will be provided. Each participant will be encouraged to complete a post-
study questionnaire outlining their experiences.         
 
5.1.5  Stage 5: Final analysis 
The objective of the final analysis will be to assess if both the primary and secondary outcomes have been 
met. As with the preliminary analysis, participants are not required at this stage. Measurements of validated 
parameters will be obtained from each data set (initial and 3-month follow up) from each participant. These 
measurements as well as will be compared between time periods to assess if (a) postpartum patients continue 
to perform PFE; (b) are they still effective; and (c) is visual biofeedback more useful than no biofeedback.  
 
 

 
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5.2 CONSORT Flow diagram 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Gynaecology Pelvic Floor Assessment Clinic 
Written informed consent taken. 
SIN assigned to participant. 
Opportunity to participate in study. 
Pre-study questionnaire, 
history and clinical 
examination 
TPUS of pelvic floor 
without visual biofeedback 
Repeat TPUS of pelvic floor without visual 
biofeedback. 
Post study questionnaire 
Comparison of groups and evaluation of 
outcomes 
TPUS of pelvic floor with 
visual biofeedback 
Pre-study questionnaire, 
history and clinical 
examination 
Inclusion/Exclusion criteria 
Patient information leaflet provided 
Randomisation 
STUDY ARM 
CONTROL ARM 
3-month follow up 
Stage 1: 
Recruitment and 
Randomisation 
Stage 5:  
Final Analysis 
Stage 4:  
Follow up 
Assessment  
Stage 3: 
Preliminary 
analysis and 
Interim Report 
Stage 2: 
Assessment 

 
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5.3 Statistical analysis 
Statistical testing will be performed using IBM SPSS statistics version 29.0 (IBM Corp. Armonk, NY). 
Interclass correlation coefficient with Bland-Altman plots will be produced for reliability analysis.  Parametric 
tests will be conducted to compare the control group with study group.  
 
6 
SAFETY MEASUREMENTS 
 
6.1 Definitions 
Serious adverse event (SAE) in relation to human biomedical research, means any untoward medical 
occurrence as a result of any human biomedical research which: 
• results in or contributes to death 
• is life-threatening 
• requires in-patient hospitalisation or prolongation of existing hospitalisation 
• results in or contributes to persistent or significant disability/incapacity or 
• results in or contributes to a congenital anomaly/birth defect 
• results in such other events as may be prescribed  
 
Adverse event (AE) in relation to human biomedical research means any untoward medical occurrence as a 
result of any human biomedical research which is NOT serious.  Adverse event can be any unfavourable and 
unintended sign (including an abnormal laboratory finding), symptom, or disease possibly/ probably/ 
definitely associated with the participant in the human biomedical research. 
 
6.2 Collecting, Recording and Reporting of Serious Adverse Events (SAEs) to CIRB 
The reporting requirements will be in accordance to the reporting requirements published on CIRB website 
at the time when the event took place. 
 
Only related SAEs (definitely/ probably/ possibly) will be reported to CIRB. Related means there is a 
reasonable possibility that the event may have been caused by participation in the research.   
 
The investigator is responsible for informing CIRB after first knowledge that the case qualifies for reporting. 
Follow-up information will be actively sought and submitted as it becomes available.  
 
Related AEs will not be reported to CIRB.  However, the investigator is responsible to keep record of such 
AEs cases at the Study Site File. 
 
6.3 Data Safety Monitoring Plan 
 
The principal investigator will be responsible for data monitoring and safety. It will be their responsibility to 
ensure that any SAEs and AEs are reported to the CIRB. Confidentiality of participants will be protected at 
all times with only the SIN being used to identify outcome data during the study. The study team will convene 
on a monthly basis to ensure the completeness of records and integrity of study data. 
 
 

 
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6.4 Complaint Handling  
The patient information leaflet will provide contact information of the study team should a participant wish 
to lodge a complaint. The PI will be informed immediately of any complaints that arise and will be responsible 
for resolving them.  
 
7 
DATA ANALYSIS 
 
7.1 Data Quality Assurance 
Three stages of quality assurance will take place. 
1. Ensure homogeneity of the study and control groups.  
• Statistical testing will be performed to ensure that the groups are well matched in reference 
to age, BMI, mode of vaginal delivery, and parity and that no confounding factors are present 
that can compromise the results of the study. This will be unlikely due to the nature of the 
randomization process, but formal assessment will nonetheless be performed.  
2. Determine reproducibility of the ultrasound measurements.  
• An inter- and intra-observer variability analysis will be conducted. This will involve two 
trained urogynaecologists independently measuring pelvic diameters and areas on a sample 
of cases after which an interclass correlation coefficient can be calculated to assess inter-
observer reliability.  
3. Comparative analysis.  
• This is to ensure that strength of contraction measured by ultrasound corresponds well with 
those found on clinical examination using the Modified Oxford Scale. This will validify the 
use of the above ultrasound parameters as a clinical assessment tool.  
 
7.2 Data Entry and Storage 
Data collected from the study will be in the form of two linked sets: 
1. Clinical and Demographic data 
• This is gathered from the history taking and electronic medical records (EMR) via the Citrix 
application. It includes data such as age, body mass index, mode of delivery, symptomology 
and findings on clinical examination. 
• Participant questionnaires. These will be hardcopy files completed in writing with only the 
SIN printed on them. 
2. Ultrasound data 
• This is derived from the ultrasound images from each participant. It includes measurements 
made of the pelvic hiatus during rest and maximal contraction.  
 
As previously mentioned, participants recruited to the study will be assigned a study identifier number (SIN). 
This SIN will be documented on their hospital EMR, which is only accessible by members of the patient’s 
clinical care team. Clinical and demographic data lifted from the EMR from each participant will contain de-
identified data and will be stored only on the hospital’s secure network. Data files will be password encrypted 
with only members of the study team having access to them. These measures will ensure that it will not be 
possible to retroactively access patient-identifiable information using the SIN. However, should the need 
arise, the clinical care team who is managing the patient could potentially request the data with authorisation 
from the study team.        
  
For ultrasound data, images acquired from each participants assessment will be stored on the ultrasound 
machine only. The images will be tagged to the SIN so only the study team is able to link the demographic 

 
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and clinical data with data collected from the ultrasound images. No identifiable information will be stored 
on the ultrasound machine.  
 
Electronic data will only be stored on hospital computers under the login credentials of the study team. 
These are password encrypted computers and, as data will be stored on the study team’s virtual drive, access 
to data will only be available to members of the study team. Written, hardcopy data (participant 
questionnaires, consent forms) will be kept in a single, locked filing cabinet that can only be accessed by 
member of the study team.   
 
8 
SAMPLE SIZE AND STATISTICAL METHODS 
 
8.1 Determination of Sample Size  
Effective pelvic floor muscle contractions are observed in 27% of women who undergo pelvic floor muscle 
training [2] while other biofeedback methods have demonstrated an improvement of up to 58%[3]. For our 
primary outcome measure, to demonstrate equivalence to other biofeedback tools, a minimum sample size 
of 78 participants will be required (Power 80%, alpha 0.05). This calculation is based upon two independent 
groups with a dichotomous primary outcome measure (i.e effective pelvic floor muscle contraction or not) 
Taking into account a potential 20% dropout rate, a further 16 participants will be required - 94 participants 
in total (47 in each arm).  
 
8.2 Statistical and Analytical Plans 
a. General considerations 
Both groups will be evaluated for homogeneity. Parametric t-tests and Chi-squared analysis will be 
used to determine if groups are well matched. Bland-Altman plots with interclass correlation 
coefficients will be used to determine if there is any significant degree of inter and intra-observer 
variability between ultrasound measurements.  
b. Safety Analyses 
The study presents very little physical risks to participants. A safety review will nonetheless be 
conducted during the preliminary analysis. All reportable SAEs and AEs will be compiled and a 
determination will be made as to whether to continue the study or not. 
c. Interim Analyses 
The interim analysis will focus on the primary outcome of whether adding visual biofeedback with 
TPUS improves the effectiveness of PFMT. Details of the interim analysis were outlined in Section 
5.1.3.  
 
9 
DIRECT ACCESS TO SOURCE DATA/DOCUMENTS 
The investigator(s)/institution(s) will permit study-related monitoring, audits and/or IRB review and 
regulatory inspection(s), providing direct access to source data/document. 
 
10 
QUALITY CONTROL AND QUALITY ASSURANCE 
Data will be evaluated for quality on a monthly basis. In addition to ensuring participant homogeneity, 
ultrasound measurement reliability and comparative analysis, data sets will be monitored for completeness 
and validity. Adherence to the study protocol will be ensure through regular data reviews by the study team 
and it will be the responsibility of the PI to ensure the data entries are accurate.    
 

 
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11 
ETHICAL CONSIDERATIONS 
This study will be conducted in accordance with the ethical principles that have their origin in the Declaration 
of Helsinki and that are consistent with the Good Clinical Practice and the applicable regulatory 
requirements. 
 
This final Study Protocol, including the final version of the Participant Information and Consent Form, must 
be approved in writing by the Centralised Institutional Review Board (CIRB), prior to enrolment of any 
patient into the study. 
 
The principal investigator is responsible for informing the CIRB of any amendments to the protocol or other 
study-related documents, as per local requirement. 
 
11.1 Informed Consent 
Written, informed consent will be obtained from all participants prior to enrolment into the study. Consent 
will be taken only by members of the study team. Provisions will be made for translation for non-English 
speaking participants. Vulnerable populations and those lacking capacity to provide consent will not be 
recruited to the study. All study team members will abide by GCP guidelines and comply with the ethical 
principles that have their origin in the Declaration of Helsinki. 
 
11.2 Confidentiality of Data and Patient Records 
Confidentiality of participants will be maintained throughout the study. All participants are assigned a SIN 
upon enrolment and any data gathered will be deidentified.   
 
12 
PUBLICATIONS 
All publication related decisions will be discussed amongst the study team members with the PI giving final 
approval of decisions.  
  
13 
RETENTION OF STUDY DOCUMENTS 
Records for all participants, including CRFs, all source documentation (containing evidence to study 
eligibility, history and physical findings, laboratory data, results of consultations, etc.) as well as IRB records 
and other regulatory documentation will be retained by the PI in a secure storage facility. The storage will be 
in accordance with the SingHealth CIRB guideline on Retention of Research Data and Records and will be 
stored for a minimum period of 6 years after completion of the study. The records will be accessible for 
inspection and copying by authorized authorities.  
 
14 
FUNDING AND INSURANCE 
This study is self-funded and will be insured under the National Clinical Trial Insurance Policy. 
 
 
 

 
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15 
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