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Trial registered on ANZCTR


Registration number
ACTRN12621000405819
Ethics application status
Approved
Date submitted
10/02/2021
Date registered
14/04/2021
Date last updated
10/11/2024
Date data sharing statement initially provided
14/04/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Early versus late artificial rupture of membranes during oxytocin induction of labour : A randomised controlled trial
Scientific title
Impact of early versus late artificial rupture of membranes during oxytocin induction of labour on the incidence of chorioamnionitis : A randomised controlled trial
Secondary ID [1] 303258 0
Nil known
Universal Trial Number (UTN)
U1111-1264-8374
Trial acronym
ARM Trial
Linked study record

Health condition
Health condition(s) or problem(s) studied:
chorioamnionitis 320523 0
induction of labour 320524 0
Condition category
Condition code
Reproductive Health and Childbirth 318383 318383 0 0
Other reproductive health and childbirth disorders
Reproductive Health and Childbirth 318860 318860 0 0
Complications of newborn
Infection 318861 318861 0 0
Other infectious diseases

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This is a randomised controlled trial comparing women undergoing oxytocin induction of labour to early versus late artificial rupture of membranes (ARM).
Late ARM - Oxytocin infusion is commenced. ARM will not be performed before 6cm dilation unless the oxytocin infusion commenced 12 hours prior and the woman is not yet 6cm dilated. In this case, the ARM will be performed at that time.

The ARM procedure is performed via performing a vaginal examination with a gloved hand and placing a thin plastic device through the cervix of the woman. The examiner then uses the end of the device to create a small hole in the amniotic membrane.
This procedure usually takes 1-2 minutes.
The procedure is performed by either the midwife or the doctor.
Medical records will be audited as the time of ARM is always recorded.

Oxytocin induction of labour is the method at the Auckland City Hospital. There is a standard protocol that the midwives follow to administer a sufficient dosage to women undergoing induction. The starting dose is 1-2 milliunits per minute. Oxytocin is administered intravenously via an infusion. There is no maximum duration of administration. However, it would be unusual for an induction of labour to take longer than 72 hours.
Intervention code [1] 319608 0
Treatment: Other
Comparator / control treatment
Early ARM - ARM is performed within 60 minutes (either before or after) of commencement of oxytocin

In this group, the ARM will be performed within 60 minutes of oxytocin starting. In most cases the midwife will perform the ARM immediately after starting the infusion. However, it it also acceptable to perform the procedure prior to starting the infusion. The timing will not be dependent on the degree of dilation as all women being randomized will already have a cervix dilated enough to permit ARM.
Control group
Active

Outcomes
Primary outcome [1] 326468 0
Diagnosis of chorioamnionitis.
Chorioamnionitis is defined as maternal temperature of greater than or equal to 38°C OR 2 maternal temperatures of >37.5°C AND the choice to treat for chorioamnionitis with antibiotics
Timepoint [1] 326468 0
By birth of the neonate

This outcome will be assessed via medical record review. Diagnosis and treatment of chorioamnionitis is recorded in the medical chart as well as the medication chart.
Secondary outcome [1] 391580 0
Caesarean birth - overall incidence of Caesarean birth post-induction
Timepoint [1] 391580 0
By birth of the neonate

This outcome will be assessed via medical record review. An operative report will be recorded in the event that a caesarean is performed.
Secondary outcome [2] 391582 0
Caesarean birth for fetal heart rate abnormality
Timepoint [2] 391582 0
By birth of the neonate

This outcome will be assessed via medical record review. An operative report with the operative indication(s) will be recorded in the event that a caesarean is performed.
Secondary outcome [3] 391583 0
Caesarean birth for labour dystocia
Timepoint [3] 391583 0
By birth of the neonate

This outcome will be assessed via medical record review. An operative report with the operative indication(s) will be recorded in the event that a caesarean is performed.
Secondary outcome [4] 391584 0
Rate of fetal heart rate abnormalities
Timepoint [4] 391584 0
By birth of the neonate

This outcome will be assessed via medical record review. An operative report with the operative indication(s) will be recorded in the event that a caesarean or instrumental vaginal birth is performed for fetal heart rate abnormalities. The midwife also performs a checklist after each birth which details the presence or absence of fetal heart rate abnormalities.
Secondary outcome [5] 391585 0
Rate of fetal heart rate abnormalities resulting in fetal scalp lactate sampling
Timepoint [5] 391585 0
By birth of the neonate

This outcome will be assessed via medical record review. Fetal scalp lactate sampling and the results of the sampling are entered into the medical record.
Secondary outcome [6] 391586 0
Rate of fetal heart rate abnormalities resulting in instrumental vaginal delivery
Timepoint [6] 391586 0
By birth of the neonate

This outcome will be assessed via medical record review. An operative report with the operative indication(s) will be recorded in the event that a caesarean or instrumental vaginal birth is performed for fetal heart rate abnormalities. The midwife also performs a checklist after each birth which details the presence or absence of fetal heart rate abnormalities.
Secondary outcome [7] 391589 0
Rate of maternal temperature greater than or equal to 38°C
Timepoint [7] 391589 0
By birth of the neonate

This outcome will be assessed via medical record review. The observation chart contains recordings of the maternal temperature readings.
Secondary outcome [8] 391592 0
Rate of postpartum endometritis
Timepoint [8] 391592 0
By diagnosis made within 7 days of birth

This outcome will be assessed via medical record review. The data will be available in the clinical record and treatment will be available in the medication chart.
Secondary outcome [9] 391593 0
Rate of infants born with 5 minute Apgar Scores <7
Timepoint [9] 391593 0
By data imputed 5 minutes post-delivery

This outcome will be assessed via medical record review. The neonatal APGAR scores are recorded in the delivery summary.
Secondary outcome [10] 391594 0
Proportion of infants born with abnormal cord blood lactate levels greater than or equal to 4.0
Timepoint [10] 391594 0
By data imputed from birth

This outcome will be assessed via medical record review. The neonatal cord blood gas readings are recorded in the delivery summary.
Secondary outcome [11] 391596 0
Average time to vaginal delivery
Timepoint [11] 391596 0
By birth of the neonate

This outcome will be assessed via medical record review. The duration from start of oxytocin to delivery of the neonate will be calculated.
Secondary outcome [12] 391597 0
Average time from rupture of membranes to vaginal delivery
Timepoint [12] 391597 0
By birth of the neonate

This outcome will be assessed via medical record review. The duration from start rupture of membranes to delivery of the neonate will be calculated.
Secondary outcome [13] 391598 0
Rate of Neonatal Intensive Care Unit (NICU) admission
Timepoint [13] 391598 0
By discharge from hospital of neonate

This outcome will be assessed via medical record review.
Secondary outcome [14] 391599 0
Cost effectiveness
Timepoint [14] 391599 0
By discharge of both mother and baby from hospital

This outcome will be assessed via medical record review. The cost of length of stay (in days) for both mother and baby will be assessed.
Secondary outcome [15] 392748 0
Proportion of infants born with abnormal cord blood pH less than or equal to 7.10
Timepoint [15] 392748 0
By data imputed after delivery.

This outcome will be assessed via medical record review. The neonatal cord blood gas readings are recorded in the delivery summary.
Secondary outcome [16] 428506 0
Rate of maternal temperature of >37.5°C on single occasion during labour
Timepoint [16] 428506 0
By birth of the neonate This outcome will be assessed via medical record review. The observation chart contains recordings of the maternal temperature readings.
Secondary outcome [17] 428507 0
Rate of maternal temperature of >37.5°C on single occasion during labour
Timepoint [17] 428507 0
By birth of the neonate This outcome will be assessed via medical record review. The observation chart contains recordings of the maternal temperature readings.
Secondary outcome [18] 428508 0
Rate of maternal temperature of >37.5°C on two occasions during labour
Timepoint [18] 428508 0
By birth of the neonate This outcome will be assessed via medical record review. The observation chart contains recordings of the maternal temperature readings.
Secondary outcome [19] 428509 0
Rate of maternal temperature of >37.5°C on two occasions during labour
Timepoint [19] 428509 0
By birth of the neonate This outcome will be assessed via medical record review. The observation chart contains recordings of the maternal temperature readings.

Eligibility
Key inclusion criteria
Pregnant women with a live singleton cephalic presentation
Planning IOL at greater than or equal to 37 weeks gestation
On admission for IOL, or for after cervical ripening with intact membranes
Cardiotocography normal
Minimum age
14 Years
Maximum age
55 Years
Sex
Females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Previous caesarean delivery
Major fetal congenital anomaly or known chromosomal abnormality
Fetal growth restriction with Absent or Reverse End Diastolic Flow noted on umbilical artery Doppler (Abnormal pulsatility index of the Middle Cerebral Artery or Umbilical Artery or abnormal CPR are permissible)
Participant in OBLIGE Study

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)
Participants will not be randomized until ready for study procedures. The randomization scheme is electronic and hence allocation is concealed until this randomization occurs.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Electronic randomization scheme run by the Liggins Institute.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
Descriptive data will be presented on the study groups.
Analyses will follow the principle of intention-to-treat.
Multivariable models may be used, especially if baseline differences are found between groups.
Binary endpoints will be analysed utilizing chi squared analysis. Continuous outcomes will also be presented (time to vaginal delivery, for example). Outcomes with three or more potential findings will be determined utilizing ANOVA.
A p value of 0.05 will be considered statistically significant. There are multiple secondary outcomes. These will be reported with p values.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
27/04/2021
Actual
3/06/2021
Date of last participant enrolment
Anticipated
1/09/2026
Actual
Date of last data collection
Anticipated
1/11/2026
Actual
Sample size
Target
500
Accrual to date
316
Final
Recruitment outside Australia
Country [1] 23438 0
New Zealand
State/province [1] 23438 0
North Island

Funding & Sponsors
Funding source category [1] 307667 0
University
Name [1] 307667 0
University of Auckland
Country [1] 307667 0
New Zealand
Funding source category [2] 312604 0
University
Name [2] 312604 0
University of Auckland - Nurture Grant
Country [2] 312604 0
New Zealand
Primary sponsor type
Individual
Name
Meghan Hill
Address
The University of Auckland
Private Bag 92019
Auckland 1142
New Zealand
Country
New Zealand
Secondary sponsor category [1] 308507 0
None
Name [1] 308507 0
Address [1] 308507 0
Country [1] 308507 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 307705 0
Northern A Health and Disability Ethics Committee
Ethics committee address [1] 307705 0
Health and Disability Ethics Committees
Ministry of Health
133 Molesworth Street
PO Box 5013
Wellington
6011
Ethics committee country [1] 307705 0
New Zealand
Date submitted for ethics approval [1] 307705 0
14/07/2020
Approval date [1] 307705 0
01/10/2020
Ethics approval number [1] 307705 0
20/NTA/122

Summary
Brief summary
Induction of labour (IOL) is one of the most common procedures performed in pregnant women, with approximately 35% of labours being induced at the Auckland District Health Board (ADHB). There are multiple induction agents that may be used for IOL, including prostaglandins, catheters and oxytocin infusion. The approach to induction of labour differs internationally and within institutions within the same country. There is no risk-free way to give birth, only interventions that may increase or decrease risks in different populations. Our study aims to assess if there is a way to decrease the risk of labour complications by delaying amniotomy until women are in established labour. We intend to perform a randomised controlled trial to assess labour and birth outcomes in women undergoing oxytocin infusion induction of labour. Participants will be randomised to an early artificial rupture of membranes (ARM) group or a late ARM group. We hypothesize that women in the late ARM group will have a lower rate of intraamniotic infection complicating their labours (chorioamnionitis). Further, we hypothesize that women with late ARM will have a lower rate of caesarean delivery and a lower rate of fetal heart rate abnormalities in labour. Other maternal and neonatal outcomes are also included in our secondary analyses. We intend to survey study participants following their births to assess satisfaction with their inductions.
Trial website
www.ARM.auckland.ac.nz
Trial related presentations / publications
Public notes
www.ARM.auckland.ac.nz

The trial website can be accessed at the above address.

Contacts
Principal investigator
Name 108210 0
Dr Meghan Hill
Address 108210 0
The University of Auckland
Private Bag 92019
Auckland 1142
New Zealand
Country 108210 0
New Zealand
Phone 108210 0
+64 9 373 7599
Fax 108210 0
Email 108210 0
[email protected]
Contact person for public queries
Name 108211 0
Meghan Hill
Address 108211 0
The University of Auckland
Private Bag 92019
Auckland 1142
New Zealand
Country 108211 0
New Zealand
Phone 108211 0
+64 9 373 7599
Fax 108211 0
Email 108211 0
[email protected]
Contact person for scientific queries
Name 108212 0
Meghan Hill
Address 108212 0
The University of Auckland
Private Bag 92019
Auckland 1142
New Zealand
Country 108212 0
New Zealand
Phone 108212 0
+64 9 373 7599
Fax 108212 0
Email 108212 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
This is not something that has been built into our consent process.
Data will be available for reviewers at the time that this study is submitted for publication.


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
10485Study protocol  [email protected]
10486Informed consent form  [email protected]



Results publications and other study-related documents

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

Documents added automatically
No additional documents have been identified.