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Trial registered on ANZCTR


Registration number
ACTRN12616000739415
Ethics application status
Approved
Date submitted
15/03/2016
Date registered
6/06/2016
Date last updated
9/03/2022
Date data sharing statement initially provided
11/02/2019
Date results information initially provided
9/03/2022
Type of registration
Prospectively registered

Titles & IDs
Public title
Comparing two methods of starting an induction of labour in pregnant women (balloon at home versus vaginal prostaglandins in hospital) to assess chance of caesarean section
Scientific title
Comparison of low-risk pregnant women undergoing induction of labour at term by outpatient balloon or inpatient prostaglandin in order to assess caesarean section rate; a randomised controlled trial
Secondary ID [1] 288759 0
nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Induction of labour 298006 0
Condition category
Condition code
Reproductive Health and Childbirth 298163 298163 0 0
Childbirth and postnatal care

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants will present themselves to the hospital Assessment area on the day of their scheduled induction of labour. The research midwife will confirm their consent to participate in the trial. They will then be randomized to the intervention or control group. Women in the intervention group will then receive an explanation of the balloon insertion procedure from the doctor or midwife on duty and have an opportunity to ask questions. The foley balloon is the device which will be used. It is a flexible catheter that is threaded up the cervical canal, and the balloon inflated just above the internal os with 50mL sterile water. This requires the woman to be in lithotomy position on a gynaecological procedure table. The procedure takes five minutes and will be performed by the midwife or doctor on duty, Afterwards, the woman will be asked to rate her discomfort during the procedure (VAS score) and will then be discharged from hospital with an information sheet on what to expect, when to return to hospital and a phone number to ring if concerned. If the balloon falls out, or if contractions start, or if she has spontaneous rupture of membranes, she would be instructed to return to hospital. If no concerns, she will return to hospital the following day (18-24 hours) and the balloon will be removed by the midwife on duty. Then the induction will be continued as clinically appropriate.
Intervention code [1] 294196 0
Treatment: Devices
Comparator / control treatment
Participants will present themselves to the hospital assessment area on the day of their scheduled induction of labour. The research midwife will confirm their consent to participate in the trial. They will then be randomized to the intervention or control group. Women in the control group will then receive an explanation of the prostaglandin (PG) vaginal gel or cervidil insertion procedure from the doctor or midwife on duty and have an opportunity to ask questions. The Prostin PG gel or Cervidil PG controlled-release insert is placed in the vagina by the midwife or doctor on duty at the same time as a routine cervix examination, and takes an extra one to two minutes. Afterwards, the woman will be asked to rate her discomfort during the procedure (VAS score). She will remain in hospital. The timing and dose of each PG gel/insert can be at the discretion of the clinical team, taking into account parity and Bishop score. The assessment and administration of PG gel/insert will be repeated regularly (not < 6 hours apart for gel; not < 12 hours apart for insert) until ARM is possible and appropriate, or if labour establishes spontaneously, or SRM, or if patient/clinician prefer to switch to balloon, or to a maximum of 6 doses for gel; maximum of 2 doses for insert. At any point that the woman starts to feel regular painful uterine tightenings, the midwife will perform a CTG. Following ARM, the woman will be transferred to labour and birthing suite for intravenous oxytocin infusion and monitoring as per local protocols.
Control group
Active

Outcomes
Primary outcome [1] 297675 0
Caesarean section rate, assessed by review of medical records
Timepoint [1] 297675 0
birth
Secondary outcome [1] 321779 0
time from commencement of induction (placement of balloon or first dose of prostaglandins) to time of birth; assessed by review of medical records
Timepoint [1] 321779 0
birth
Secondary outcome [2] 321780 0
uterine hyperstimulation, if treatment was required. hyperstimulation is defined as tachysystole (> 5 contractions in 10 minutes) or hypertonus (contractions lasting > 2 minutes) in the presence of fetal heart rate abnormalities; assessed by review of medical records
Timepoint [2] 321780 0
birth
Secondary outcome [3] 321781 0
antepartum haemorrhage after start of IOL, cause (placenta abruption, other), timing
(during IOL, during labour, during birth), associated with fetal and/or maternal
complications; assessed by review of medical records
Timepoint [3] 321781 0
birth
Secondary outcome [4] 321782 0
Uterine rupture, defined as clinically significant rupture involving the full thickness of the uterine wall and requiring surgical repair; assessed by review of medical records
Timepoint [4] 321782 0
birth
Secondary outcome [5] 321783 0
rate of return to hospital prior to planned time of review; assessed by review of medical records
Timepoint [5] 321783 0
birth
Secondary outcome [6] 321784 0
discomfort during placement of balloon or first vaginal prostaglandin hormone (VAS pain score)
Timepoint [6] 321784 0
immediately after placement
Secondary outcome [7] 321785 0
need for second method of cervix ripening (and reason); assessed by review of medical records
Timepoint [7] 321785 0
birth
Secondary outcome [8] 321786 0
use of oxytocin infusion and at what cervix dilation started; assessed by review of medical records
Timepoint [8] 321786 0
birth
Secondary outcome [9] 321787 0
use of epidural anaesthesia and at what cervix dilation placed; assessed by review of medical records
Timepoint [9] 321787 0
birth
Secondary outcome [10] 321788 0
chorioamnionitis; defined clinically as fever during labour with maternal or fetal tachycardia and received broad spectrum IV antibiotics; assessed by review of medical records
Timepoint [10] 321788 0
birth
Secondary outcome [11] 321789 0
assisted vaginal birth (forceps or ventouse) and primary reason; assessed by review of medical records
Timepoint [11] 321789 0
birth
Secondary outcome [12] 321790 0
if caesarean delivery, then primary reason and at what cervix dilation; assessed by review of medical records
Timepoint [12] 321790 0
birth
Secondary outcome [13] 321791 0
post-partum haemorrhage within 24 hours of birth, categorised as estimated blood loss 500-1000, 1001-1500, > 1500mL; assessed by review of medical records
Timepoint [13] 321791 0
post natal discharge from hospital
Secondary outcome [14] 321792 0
admission to intensive care unit or equivalent; assessed by review of medical records
Timepoint [14] 321792 0
post natal discharge from hospital
Secondary outcome [15] 321793 0
maternal satisfaction; assessed by a questionnaire designed for this study, based on questionnaire designed for similar studies, such as ACTRN12614000039684 (verbal permission from principle investigator to use)
Timepoint [15] 321793 0
post natal discharge from hospital
Secondary outcome [16] 321794 0
composite measure of fetal and neonatal outcome comprising one or more of: Admission to Level 2 neonatal critical care nursery; Need for intubation and/or external cardiac compressions; Cord arterial pH < 7.10 or base excess 12 or greater or lactate 8 or greater; Hypoxic ischaemic encephalopathy; Neonatal seizure; Infection (as defined by neonatal antibiotic administration); Persistent pulmonary hypertension of the newborn (PPHN); Stillbirth; Early neonatal death; assessed by review of medical records
Timepoint [16] 321794 0
6 weeks
Secondary outcome [17] 321795 0
Maternal length of stay in hospital from antenatal admission to Assessment unit, to post natal discharge home; assessed by review of medical records
Timepoint [17] 321795 0
post natal discharge from hospital
Secondary outcome [18] 321796 0
hospital staff satisfaction; assessed by a questionnaire designed for this study, based on questionnaire designed for similar studies, such as ACTRN12614000039684 (verbal permission from principle investigator to use)
Timepoint [18] 321796 0
birth
Secondary outcome [19] 321797 0
Cost effectiveness; assessed by data linkage to hospital or country-wide cost lists, including:
Pharmaceutical, equipment and consumable costs;
Health care utilisation costs;
Incremental cost effective ratio for caesarean rate.
Timepoint [19] 321797 0
post natal discharge from hospital
Secondary outcome [20] 321963 0
Reason for return to hospital prior to planned time of review; assessed by review of medical records
Timepoint [20] 321963 0
birth
Secondary outcome [21] 321964 0
discomfort during artificial rupture of membranes (VAS pain score);
Timepoint [21] 321964 0
immediately after ARM
Secondary outcome [22] 321968 0
Neonatal 5 minute Apgar score less than 7; assessed by medical records
Timepoint [22] 321968 0
birth
Secondary outcome [23] 335143 0
Admission to neonatal intensive care unit (NICU)/special care baby unit (SCBU); respiratory
support (ventilation, CPAP, HHHF); mechanical ventilation (CMV or HFOV) and duration; assessed by review of medical records
Timepoint [23] 335143 0
post natal discharge

Eligibility
Key inclusion criteria
Women with a live singleton cephalic presentation planning induction of labour at 37 weeks’ gestation or more
Minimum age
16 Years
Maximum age
50 Years
Sex
Females
Can healthy volunteers participate?
Yes
Key exclusion criteria
major congenital anomaly; suspected severe fetal growth restriction (defined as estimated fetal weight less than 10th centile or abdominal circumference less than or equal to 5th centile AND oligohydramnios or abnormal dopplers, OR estimated fetal weight less than 3rd centile); previous caesarean; ruptured membranes; bishop score 7 or more at commencement of induction; maternal risk or fetal compromise that would necessitate monitoring the woman or her baby in hospital; not willing to stay within 60 minutes of hospital; does not speak English or have someone with them who speaks English.

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)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
Data will be collected electronically from hospital medical records and maternity databases, and from women and staff directly. Data will be entered into a REDCap database which is centralised, online and secure.
Sample size calculation: At Auckland Hospital in 2015, the caesarean section rate in women who had IOL (excluding women with previous caesarean) was 24.8%, almost all of whom had vaginal prostaglandins (as described above in standard care arm of trial). In the small published trial of outpatient vs inpatient balloon IOL, the caesarean section rate decreased by 14%, from 43% to 29%. Based on consultation with local and Australian obstetricians, we felt that a 6% decrease would be a clinically meaningful difference. In consultation with our statisticians, in order to detect a decrease in caesarean section rate from 24.8% to 18.8%, with 80% power and a two-sided type 1 error of 0.05, the sample size required would be 743 women for each study group. Adding a continuity correction, the final sample size is 1,552 women.
Data analysis: Baseline demographic and clinical characteristics of each group will be described. Analyses will follow the principle of intention-to-treat. Participants will be analysed according to the assigned treatment group at randomisation. Binary endpoints will be analysed using logistic regression to estimate odds ratios for the intervention. Continuous outcomes will be modelled using generalised linear models to estimate any changes in outcomes with the intervention compared to the control group. Multivariable models will control for potentially confounding variables and include hospital site. A p value of 0.05 will be considered to be statistically significant. We recognise there are a number of secondary outcomes; most will be correlated and thus we plan to report p values for these outcomes without corrections, which would be overly conservative.
Economic evaluation: Economic evaluation: Our approach will be to relate costs to outcomes for both arms of the study, allowing for the calculation of incremental cost-effectiveness ratios for the primary study outcome – caesarean delivery rate. In addition, a comparative cost analysis will be conducted to demonstrate the budget impact of wide-scale uptake of the intervention, given that length of stay and complication rates are both higher for caesarean birth rates.

Recruitment
Recruitment status
Stopped early
Data analysis
Data collected is being analysed
Reason for early stopping/withdrawal
Participant recruitment difficulties
Date of first participant enrolment
Anticipated
17/07/2017
Actual
25/10/2017
Date of last participant enrolment
Anticipated
Actual
30/11/2021
Date of last data collection
Anticipated
Actual
25/01/2022
Sample size
Target
1552
Accrual to date
Final
1087
Recruitment outside Australia
Country [1] 7705 0
New Zealand
State/province [1] 7705 0

Funding & Sponsors
Funding source category [1] 293118 0
Government body
Name [1] 293118 0
Health Research Council of New Zealand
Country [1] 293118 0
New Zealand
Funding source category [2] 296536 0
Charities/Societies/Foundations
Name [2] 296536 0
A+ Trust
Country [2] 296536 0
New Zealand
Funding source category [3] 301929 0
Charities/Societies/Foundations
Name [3] 301929 0
Maurice and Phyllis Paykel Trust
Country [3] 301929 0
New Zealand
Primary sponsor type
University
Name
Department of Obstetrics and Gynaecology, FMHS, University of Auckland
Address
Private Bag 92019
Auckland 1142
Country
New Zealand
Secondary sponsor category [1] 292571 0
Hospital
Name [1] 292571 0
Auckland District Health Board
Address [1] 292571 0
c/o ADHB Research Office
Level 14, Support Building, Auckland Hospital
Private Bag 92024
Auckland
Country [1] 292571 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 294616 0
HDEC (Health and Disability Ethics Committee)
Ethics committee address [1] 294616 0
Ministry of Health
Ethics Department
Freyberg Building
Reception – Ground Floor
20 Aitken Street
Wellington 6011
Ethics committee country [1] 294616 0
New Zealand
Date submitted for ethics approval [1] 294616 0
31/03/2016
Approval date [1] 294616 0
15/10/2016
Ethics approval number [1] 294616 0

Summary
Brief summary
Rationale: The induction of labour rate in New Zealand is high. Mechanical methods of induction in hospital are safe and effective. However, most women in New Zealand have induction using pharmacological methods. Trials are needed to determine the safety and effectiveness of outpatient induction with balloon catheter. Outpatient balloon induction has the potential to give women more choice and improve satisfaction, and to save on health care costs, while maintaining safe outcomes for mothers and their babies.

Aim: To compare two management protocols for initial management of induction of labour

Objective: To demonstrate safety, clinical effectiveness and cost effectiveness for mothers and babies who are allowed to go home after commencing a balloon induction, versus remaining in hospital after commencing a prostaglandin induction.

Design: This will be a multi-centre randomized controlled trial across New Zealand. Women will be identified by clinicians in antenatal clinics when induction of labour is recommended. Women will be included if they have a live singleton cephalic presentation and induction of labour is planned at 37 weeks’ or more gestation, and excluded if monitoring in hospital is necessary. Eligible women will be recruited by a research midwife and provide written consent to participate. The primary outcome is clinical effectiveness as measured by caesarean section rate. Secondary outcomes include safety as measured by rates of adverse events (placental abruption; stillbirth; neonatal admission to intensive care); cost effectiveness; and maternal and staff satisfaction.

Implications: If outpatient balloon induction is found to be as safe and effective as inpatient prostaglandin induction in low-risk women, then district health boards can incorporate this protocol into their clinical guidelines. Moreover, this evidence-based recommendation can be added to the Auckland Consensus Guideline (2014) which will hopefully become a national guideline following broad consultation, enabling consistency of practice across the country.
Trial website
www.oblige.auckland.ac.nz
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 64378 0
Dr Michelle Wise
Address 64378 0
Private Bag 92019
Department of Obstetrics and Gynaecology, FMHS, University of Auckland
Auckland 1142
Country 64378 0
New Zealand
Phone 64378 0
+649-923-9488
Fax 64378 0
Email 64378 0
m.wise@auckland.ac.nz
Contact person for public queries
Name 64379 0
Ms Mariska Oakes-ter Bals
Address 64379 0
Private Bag 92019
Department of Obstetrics and Gynaecology, FMHS, University of Auckland
Auckland 1142
Country 64379 0
New Zealand
Phone 64379 0
+6499239808
Fax 64379 0
Email 64379 0
m.terbals@auckland.ac.nz
Contact person for scientific queries
Name 64380 0
Dr Michelle Wise
Address 64380 0
Private Bag 92019
Department of Obstetrics and Gynaecology, FMHS, University of Auckland
Auckland 1142
Country 64380 0
New Zealand
Phone 64380 0
+649-923-9488
Fax 64380 0
Email 64380 0
m.wise@auckland.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
all data that is non-identifiable
When will data be available (start and end dates)?
at end of study and after submission for publication; end of study anticipated to be August 2020 and IPD availability to continue for another 5 years (August 2025)
Available to whom?
to other researchers in the field
Available for what types of analyses?
univariate and multivariable analyses, metaanalysis
How or where can data be obtained?
electronic database can be shared


What supporting documents are/will be available?

TypeCitationLinkEmailOther DetailsAttachment
Ethical approval    370330-(Uploaded-11-02-2019-10-37-23)-Study-related document.pdf
Study protocolWise MR, Marriott J, Battin M, Thompson JMD, Stitely M, Sadler L. Outpatient balloon vs inpatient prostaglandin for induction of labour (OBLIGE): a randomized controlled trial. Trials. Published online 19/02/2020. https://doi.org/10.1186/s13063-020-4061-5   370330-(Uploaded-11-02-2019-10-37-54)-Study-related document.pdf
Other    www.oblige.auckland.ac.nz


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseOutpatient Induction of Labor - Are Balloon Catheters an Appropriate Method?.2021https://dx.doi.org/10.1055/a-1308-2341
N.B. These documents automatically identified may not have been verified by the study sponsor.