Effect of Materials of Vaginal Ring Pessary for Pelvic Organ Prolapse on the Effects of Complications and Patient's Satisfaction
Phase: NA
Conditions: Pelvic Organ Prolapse
Sponsor: Princess Margaret Hospital, Hong Kong

Title of study: 
Effect of materials of vaginal ring pessary for pelvic 
organ prolapse on the effects of complications and 
patients' satisfaction: A Randomized Control Trial 
 
Date of document: 11th October: 2024 
 
 
 

Principle investigator: Dr Lo Cheuk Yin 
Resident, Department of Obstetrics and Gynaecology, Princess Margaret Hospital 
Address: Room G204, Department of Obstetrics and Gynaecology, Princess Margaret Hospital 
Contact: 64611057  
Introduction 
Pelvic organ prolapse (POP) is a common gynaecological condition which attains prevalence 
of 15% women. It causes negative impact on physical, emotional and psychosexual aspects, 
thus significantly impairs patients’ activities of daily living and quality of life. Treatment 
modalities include conservative, pessary and surgical management. Vaginal pessary is 
inexpensive, non-invasive and an attractive treatment option for women who possess high 
anaesthetic and surgical risks. Pessary-related complications include vaginal ulcer, vaginitis 
which would require temporary discontinuation of pessary use in order to prevent serious 
complications such as incarceration and fistula formation. If complications can be minimised, 
it is more likely that patients’ satisfaction can further improve. 
Vaginal pessaries are primarily made of polyvinyl chloride (PVC) or silicone. PVC has been 
the material of choice for local practice based on its long history in clinical use and cheaper 
cost. A new PVC pessary is inserted at each consultation if vaginal condition is satisfactory (1). 
In view of the increasing number of POP patients who opt for long term pessary use, silicone 
has emerged as alternative material of choice in recent years. Despite being more expensive, 
silicone pessaries can be washed and re-inserted for 20 washes/10 years if remained intact and 
not visibly damaged. As silicone pessary is more pliable, it can facilitate the process of pessary 
insertion and removal by squeezing of the pessary to pass through narrow introitus. (2) On the 
other hand, it may be more easily compressed by abdominal pressure and dislodged when 
straining. The UK clinical guideline for best practice in the use of vaginal pessaries for POP in 
2021 suggested there is no clear preference of offering one type of pessary over another, further 
supported by the latest publication of a multi-centre pessary study in the UK in 2023. (3) 
 
 

Study Objective 
 
The primary objective is to determine the effect of vaginal ring pessary material on pessary 
complications and patients’ satisfaction. The secondary objectives are to explore the effect of 
pessary material on procedural pain during pessary exchange as well as prolapse-related 
symptoms. It is hypothesised that silicone pessaries, compared to PVC pessaries, can reduce 
the rate of pessary-related complications from 30% to 10% and also result in higher patients’ 
satisfaction.  
 
Material and methods 
 
This is a single-blinded, randomised placebo-controlled trial conducted in the pessary clinic in 
Princess Margaret Hospital (PMH). The procedures are in accordance with ethical standards of 
research and the Declaration of Helsinki. Ethical approval was sought from the Hospital 
Authority Central Institutional Review Board (Central IRB). Written informed consent is 
obtained from all participants before study group allocation.  
Inclusion criteria 
 
Eligible participants are women >=18 years old who understand written traditional Chinese, 
diagnosed with stage 1-4 POP according to the standard of Pelvic organ prolapse 
Quantification (POP-Q), using PVC pessary as long term management for POP, and are willing 
to participate and provide a written informed consent.  
Exclusion criteria 
 
Participants are excluded from the study if 
1. Do not understand or comprehend written traditional Chinese 
2. Cannot provide written consent 
3. Vaginal complication requiring discontinuation of pessary use 
4. Unable to follow up clinic 6 months later 
5. Pregnant or lactating 
6. Recruited in other research studies 
Randomization 
Participants are assessed for eligibility when they present to pessary clinic for routine pessary 
care. 
Participants are recruited and assigned randomly in 1:1 ratio to receive either  
• 
Treatment arm: replacement of a new silicone pessary  
• 
Control arm: replacement of a new PVC pessary  

Participants are randomly assigned to one of the two groups in 1:1 ratio. Randomization is 
carried out by an independent statistician according to computer-generated random numbers in 
random blocks of two, four and six, allocated by sequentially numbered, sealed opaque 
envelopes. When participants are prepared for pessary care inside the examination room, the 
new pessary will be prepared by research assistant outside the examination room according to 
the allocation result. The attending staff will conduct routine pessary care including pessary 
removal, vaginal examination and pessary replacement. Participants are not informed of the 
material of the new pessary. Standard patient information leaflet regarding pessary care with 
hotlines is provided. A 6-month follow up appointment will be arranged.  
Participants will subsequently attend follow up 6 months later. A questionnaire will be given 
by the research assistant before the consultation to enquire for any pessary-related symptoms, 
and their satisfaction on the current pessary. During the consultation, the attending staff will 
remove the study pessary and assess the vaginal condition. The study is concluded by a short 
questionnaire and routine pessary care follows subsequently.  
Data Collection 
Patient age, parity,  menopausal status, stage of prolapse on presentation, previous duration of 
pessary use, history of pessary complications are obtained from hospital record as demographic 
data.  
Symptoms of pessary-related complications and patients’ satisfaction are collected by self-
administered questionnaires. Signs of pessary-related complications are assessed and 
documented by the attending staff. 
Statistical Analysis 
Baseline characteristics and outcomes of PVC pessary group and silicone pessary group are 
compared using independent t-test, Mann-Whitney U test, Pearson’s chi-square test or Fisher’s 
exact test, where appropriate.  
Odds ratio for complications with 95% confidence interval was calculated.  
The within-group changes of patient satisfaction and severity of prolapse with POP-Q were 
assessed using Wilcoxon signed-rank test.  
Sample size calculation 
Previous pessary study in our unit has shown the rate of pessary-related complications with 
follow-up interval of 6-month was 30% (only PVC pessary was available) (4). Assuming the 
complication rate of silicone pessary use with 6-month follow-up interval is 10%, configuring 
80% power of detection, 5% of beta error and 20% of dropout rate, 140 participants are needed 
for recruitment.  
 
 
 

Handling, Accessibility and Storage of Personal Data and Study Data 
 
Records identifying the subject will be kept confidential and, to the extent permitted by the 
applicable laws and/or regulations, will not be made publicly available. If the results of the trial 
are published, the subject’s identity will remain confidential.  
All participants will be replaced by a designated research code. Master list will be stored 
separately and protected with password. The electronic database and folders will be encrypted. 
Hard copies of the questionnaire will be stored in a lockable file cabinet.  
Only principal investigator, research team member and Central IRB will be granted direct 
access to the subject’s original research records for verification or clinical trial procedures 
and/or data, without violating the confidentiality of the subject, to the extent permitted by the 
applicable laws and regulations and that, by signing a written informed consent form, the 
subject or the subject’s legally authorised representative is authorising such access.  
After 3 years of study completion, hard copies will be discarded as confidential waste while 
soft copies will be deleted and unrecoverable.  
Conflicts of interest 
The author has disclosed no conflicts of interest. 
Funding or support 
This study was supported by Mini Research Grant, Clinical Research Centre, Kowloon West 
Cluster, Hospital Authority, Hong Kong SAR, China. The funding was used for the cost of the 
ring pessary  
Ethical Concern 
Any participation in a research study is completely voluntary. Any person is free to decline to 
participate for any reason. A participant can leave the research study at any time. When 
withdrawing from the study, the participant should let the research team know that he/she/they 
wishes to withdraw. A participant may provide the research team with the reasons for leaving 
the study, but is not required to provide their reason. 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Literature Reference 
1. UK clinical guideline for best practice in the use of vaginal pessaries for pelvic organ 
prolapse. 2021. 
https://thepogp.co.uk/_userfiles/pages/files/resources/uk_pessary_guideline_final_apr
il21.pdf. Date accessed: March 27, 2023 
2. Jones KA, Harmanli O. Pessary use in pelvic organ prolapse and urinary 
incontinence. Rev Obstet Gynecol. 2010 Winter;3(1):3-9. PMID: 20508777; PMCID: 
PMC2876320. 
3. Clinical effectiveness of vaginal pessary self-management vs clinic-based care for 
pelvic organ prolapse (TOPSY): a randomised controlled superiority trial Hagen, 
Suzanne et al. eClinicalMedicine, Volume 66, 102326 
4. Tam M.S., Lee V.Y.T., Yu E.L.M. et al. The effect of time interval of vaginal ring 
pessary replacement for pelvic organ prolapse on complications and patient 
satisfaction: a randomised controlled trial. Maturitas. 2019; 128: 29-35