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Trial registered on ANZCTR


Registration number
ACTRN12618000510246p
Ethics application status
Submitted, not yet approved
Date submitted
2/04/2018
Date registered
9/04/2018
Date last updated
11/03/2019
Date data sharing statement initially provided
11/03/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Measuring the clinical effectiveness and healthcare experiences for women undergoing a balloon induction of labour, where the balloon is used for 6 hours compared to 12 hours.
Scientific title
Amongst women undergoing induction of labour using a balloon catheter, is leaving the balloon in for 6 hours, compared to 12 hours, associated with similar changes in the cervix to prepare for labour, similar clinical outcomes, and a similar healthcare experience?
Secondary ID [1] 294484 0
Nil known
Universal Trial Number (UTN)
U1111-1211-6521
Trial acronym
SILVER Balloon
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Induction of labour 307248 0
Condition category
Condition code
Reproductive Health and Childbirth 306366 306366 0 0
Childbirth and postnatal care

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Women randomised to the 6-hour arm will have a balloon catheter inserted by an experienced clinician (midwife, Registrar or obstetrician) and remain in hospital, Clinical staff will endeavour to review the women at 6-hours following insertion of the balloon catheter, deflate the balloon, attempt an amniotomy and commence an oxytocin infusion as soon as possible. The induction process for women in the trial will be very similar to usual clinical practice, except that the balloon catheter will be removed at 6 hours. Protocol compliance will be monitored by a research midwife.
Intervention code [1] 300780 0
Treatment: Devices
Comparator / control treatment
Women randomised to the 12-hour arm will have a balloon catheter inserted by an experienced clinician (midwife, Registrar or obstetrician) aand remain in hospital Clinical staff will endeavour to review the women at 12-hours following insertion of the balloon catheter, deflate the balloon, attempt an amniotomy and commence an oxytocin infusion as soon as possible. The induction process for women in the trial will be very similar to usual clinical practice, Protocol compliance will be monitored by a research midwife.
Control group
Active

Outcomes
Primary outcome [1] 305379 0
Change in cervical favourability (as measured by the modified Bishop's score)
Timepoint [1] 305379 0
At time of removal of the balloon catheter
Secondary outcome [1] 345003 0
Mode of birth, as recorded in the hospital records
Timepoint [1] 345003 0
At the time of birth
Secondary outcome [2] 345004 0
Time from insertion of balloon catheter until birth, as recorded in the hospital records
Timepoint [2] 345004 0
At the time of birth
Secondary outcome [3] 345005 0
Time from amniotomy until birth, as recorded in the hospital records
Timepoint [3] 345005 0
At the time of birth
Secondary outcome [4] 345006 0
Epidural use, as recorded in the hospital records
Timepoint [4] 345006 0
At the time of birth
Secondary outcome [5] 345007 0
Admission to a neonatal nursery, as recorded in the hospital records
Timepoint [5] 345007 0
At the time of birth
Secondary outcome [6] 345008 0
Health status of the baby at time of birth will be assessed using Apgar score at 5 minutes of age, as recorded in the hospital records
Timepoint [6] 345008 0
At the time of birth
Secondary outcome [7] 345009 0
Arterial cord blood pH < 7.1, tested using an arterial blood gas analyses
Timepoint [7] 345009 0
At the time of birth
Secondary outcome [8] 345010 0
Healthcare experience (as measured by the Experiences of Induction Tool)
Timepoint [8] 345010 0
Between 48h and 7 days following birth
Secondary outcome [9] 345011 0
Total healthcare costs. Information used to calculate this will be drawn from the hospital record, patient administration system, and operating room data systems,. Where possible, this will be calculated at the patient-level using a bottom-up methodology. Where this is not possible, cost will be ascribed using the apportioned cost per minute spent in the various clinical areas. Costs will be calculated from the perspective of the hospital and the time horizon will be from hospital admission until discharge of both mother and baby.
Timepoint [9] 345011 0
Time of hospital discharge

Eligibility
Key inclusion criteria
All women with live singleton pregnancies greater than or equal to 37+0 weeks booked for induction of labour and requiring cervical priming (i.e. the cervix to be softer, shorter, dilated)
Minimum age
18 Years
Maximum age
No limit
Gender
Females
Can healthy volunteers participate?
No
Key exclusion criteria
Major congenital abnormality; multiple pregnancy; fetal death in utero; any contraindication to vaginal birth; previous caesarean section; modified Bishops score of 7 or more at commencement of induction of labour; women <18 years; inability to consent.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Randomisation will be according to computer-generated random allocation list into two study arms. Sealed opaque, sequentially numbered envelopes will be prepared. Randomisation will be performed approximately 8-24 hours prior to commencing the IOL.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation). Randomisation will be stratified by parity.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
N/A
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Statistical analyses of the data will be performed by the investigators with support from Mater Research. The initial analysis will assess the adequacy of randomization procedure to ensure comparability of the study groups. In this analysis demographic and other baseline characteristics will be compared. Primary and secondary outcomes will be assessed comparing the study groups. Analysis will be by intention-to-treat. Data from women who withdraw their consent will not be included in the analysis. Subgroup analyses will be undertaken, comparing outcomes for nulliparous versus multiparous women, and for women with more and less favourable cervices at time of commencement of IOL. The Chi squared test will be used for categorical outcomes and student’s t-test for continuous data. If imbalance is identified in important baseline characteristics or demographics, a second analysis will be undertaken controlling for these factors using multivariate analysis. The level of significance for the primary outcome measures is set at 0.05 and Bonferroni adjustment for multiple comparisons will be undertaken for secondary outcome measures.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
QLD
Recruitment hospital [1] 10532 0
Mater Mother's Hospital - South Brisbane
Recruitment postcode(s) [1] 22252 0
4101 - South Brisbane

Funding & Sponsors
Funding source category [1] 299110 0
Hospital
Name [1] 299110 0
Mater Misericordiae Ltd
Address [1] 299110 0
Raymond Terrace
South Brisbane, QLD, 4101
Country [1] 299110 0
Australia
Primary sponsor type
Hospital
Name
Mater Misericordiae Ltd
Address
Raymond Terrace
South Brisbane, QLD, 4101
Country
Australia
Secondary sponsor category [1] 298366 0
None
Name [1] 298366 0
Address [1] 298366 0
Country [1] 298366 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 300042 0
Mater Group Human Research Ethics Committee
Ethics committee address [1] 300042 0
Raymond Terrace
South Brisbane, QLD, 4101
Ethics committee country [1] 300042 0
Australia
Date submitted for ethics approval [1] 300042 0
03/04/2018
Approval date [1] 300042 0
Ethics approval number [1] 300042 0

Summary
Brief summary
Induction of labour (IOL) is one of the most frequently performed obstetric interventions. In high-income countries nearly one-third of all pregnant women undergo IOL. The process of IOL commonly involves cervical ripening, using mechanical or pharmacological methods; however, the optimum protocol of IOL remains undetermined. For almost 50 years, balloon catheters have been used to mechanically ripen the cervix. Balloon catheters apply direct pressure on the internal os of the cervix, stretching the lower uterine segment and indirectly increasing release of endogenous prostaglandins. In recent years, there has been a shift in clinical practice favouring mechanical methods in response to growing evidence of both efficacy and safety. In randomised controlled trials and meta-analyses mechanical methods appear comparable to pharmacological methods for successful IOL without the complication of uterine hyper-stimulation. Trends toward a reduction in instrumental births, fetal acidaemia and post-partum haemorrhage have also been observed with balloon IOL.

IOL using a single or double balloon catheter typically involves removal of the catheter approximately 12 hours after insertion, followed by an artificial rupture of membranes (ARM) and commencement of an oxytocin infusion. Whilst there is good data supporting its efficacy in ripening the cervix, there is limited information to guide exactly how long a balloon catheter should remain in situ. The product recommendation states “up to 12 hours”. There are just two abstracts reporting on small clinical trials comparing a 6-hour versus 12-hour insertion. The methods do not describe how the IOL was managed following removal of the balloon. These data are under-powered but nevertheless reassuring that an earlier removal of the balloon catheter is likely associated with a shorter duration of labour and is unlikely to be associated with a difference in mode of birth. There is evidence to support that a longer duration of induced labour is associated with both a poorer healthcare experience and increased costs. Hence earlier removal of the balloon catheter shows promise as a method to reduce cost, and improve the healthcare experience for women without altering clinical outcomes.

This study therefore aims to explore the clinical effectiveness and healthcare experience of women undergoing an IOL using a balloon catheter where the balloon is left in-situ for a shorter versus longer duration of time.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 82366 0
A/Prof Michael Beckmann
Address 82366 0
Level 6
Duncombe Building
Mater Health
Raymond Tce
South Brisbane, QLD, 4101
Country 82366 0
Australia
Phone 82366 0
+61731638602
Fax 82366 0
Email 82366 0
michael.beckmann@mater.org.au
Contact person for public queries
Name 82367 0
A/Prof Michael Beckmann
Address 82367 0
Level 6
Duncombe Building
Mater Health
Raymond Tce
South Brisbane, QLD, 4101
Country 82367 0
Australia
Phone 82367 0
+61731638602
Fax 82367 0
Email 82367 0
michael.beckmann@mater.org.au
Contact person for scientific queries
Name 82368 0
A/Prof Michael Beckmann
Address 82368 0
Level 6
Duncombe Building
Mater Health
Raymond Tce
South Brisbane, QLD, 4101
Country 82368 0
Australia
Phone 82368 0
+61731638602
Fax 82368 0
Email 82368 0
michael.beckmann@mater.org.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Ethics approval has not been sought
What supporting documents are/will be available?
No other documents available
Summary results
No Results