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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Pessary or Progesterone to Prevent Preterm delivery in women with a twin pregnancy and short cervical length
Scientific title
Evaluating the effectiveness of a cervical pessary to improve neonatal outcome by preventing preterm birth in women with a twin pregnancy and a short cervix.
Secondary ID [1] 289560 0
Universal Trial Number (UTN)
Trial acronym
Quad P-twins
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Short cervix in twin pregnancy 299284 0
Condition category
Condition code
Reproductive Health and Childbirth 299281 299281 0 0
Antenatal care
Reproductive Health and Childbirth 299282 299282 0 0
Fetal medicine and complications of pregnancy

Study type
Description of intervention(s) / exposure
Cerclage pessary.

This is a dome shaped silicone device which is inserted into the vagina by an obstetrician. The cerclage pessary will remain in place from the time of insertion (approx 20 weeks gestation) until approximately 36 weeks gestation, or the onset of labour, whichever occurs first.
Intervention code [1] 295152 0
Intervention code [2] 295153 0
Treatment: Drugs
Intervention code [3] 295154 0
Treatment: Devices
Comparator / control treatment
Vaginal progesterone.

Progesterone capsules containing 200mg micronised progesterone. These will be self administered by participants by placing one capsule into the vagina each night. Treatment will be from study entry ( at approx 20 weeks gestation) until approximately 36 weeks gestation, or the onset of labour, whichever occurs first.
Control group

Primary outcome [1] 298773 0
Composite adverse neonatal outcome icluding periventricular leukomalacia (PVL) > grade 1, severe respiratory distress syndrome (RDS) bronchopulmonary Dyplasia (BPD), Intraventricular Haemorrhage grade III or IV, Necrotizing Enterocolitis (NEC) > stage 1, proven sepsis, (intrapartum) stillbirth and death before discharge from the nursery. These will be assessed by review of medical records.
Timepoint [1] 298773 0
Time of delivery
Secondary outcome [1] 325154 0
Time to delivery
Preterm birth rates at 38, 32, 34, and 37 weeks gestation.
These will be assessed by medical record review
Timepoint [1] 325154 0
Time of delivery

Key inclusion criteria
Viable twin pregnancy
Cervical length less than 38mm via transvaginal ultrasound assessment
Minimum age
18 Years
Maximum age
No limit
Can healthy volunteers participate?
Key exclusion criteria
Placenta praevia
Cervical cerclage in this pregnancy
Identified major congenital anomaly
Demise of one or both twins
previous preterm birth (including of singleton)
Previous participation in the Quad P-twin study

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Treatment allocation will NOT be concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software. Stratified by site
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Data will initially be analysed according the intention to treat and outcome assessors will be blinded to treatment allocation. The main outcome variable will be assessed by calculating rates in the two groups, relative risks and 95% confidence intervals as well as numbers needed to treat. To evaluate the potential of each of the strategies, we will also perform a per protocol analysis, taking into account only those cases that were treated according to protocol.
A poor outcome rate of 15% is expected. The aim of the study is to exclude that the difference between the two groups is more than 15%. Using a power of 80% we need 89 subjects in each arm. However as each pregnancy will result in the birth of two children and there will be a dependency between the children born of one mother, it is sufficient to recruit 70 women per arm (140 in total).

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 6031 0
Womens and Childrens Hospital - North Adelaide
Recruitment hospital [2] 6032 0
Lyell McEwin Hospital - Elizabeth Vale
Recruitment postcode(s) [1] 13480 0
5006 - North Adelaide
Recruitment postcode(s) [2] 13481 0
5112 - Elizabeth Vale

Funding & Sponsors
Funding source category [1] 293932 0
Name [1] 293932 0
Women's and Children's Hospital Foundation
Address [1] 293932 0
55 King William Rd, North Adelaide SA 5006
Country [1] 293932 0
Primary sponsor type
Women's and Children's Health Network
72 King William Rd, North Adelaide SA 5006
Secondary sponsor category [1] 292755 0
Name [1] 292755 0
Address [1] 292755 0
Country [1] 292755 0

Ethics approval
Ethics application status
Ethics committee name [1] 295348 0
Women's and Children's Health Network Human Research Ethics Committee (EC00197)
Ethics committee address [1] 295348 0
72 King William Road, NORTH ADELAIDE SA 5006
Ethics committee country [1] 295348 0
Date submitted for ethics approval [1] 295348 0
Approval date [1] 295348 0
Ethics approval number [1] 295348 0

Brief summary
Preterm birth, defined as birth before 37 weeks gestation, affects 22,000 pregnancies (7.5%) in Australia each year. While advances in neonatal care and treatments for preterm babies have greatly increased the chances of survival for even the smallest babies, preterm birth is still the leading cause of newborn death. Babies born before 37 weeks are also at risk for serious health problems including breathing difficulties, feeding problems, jaundice and effects on brain functions.

Multiple pregnancy is a major risk factor for preterm birth, with 57% of twins born preterm compared to only 7% of singletons. Furthermore, 12% of twins are born before 32 weeks compared with only 2% of singletons.

A short cervix, as measured by transvaginal ultrasound during the second trimester, is a powerful predictor of preterm birth. The risk of preterm delivery increases as the cervix shortens. When cervical length is less than 22 mm, women face a 20% probability of preterm delivery, which increases to 50% when the cervical length is less than 15 mm.

Two currently available treatments used to reduce the incidence of preterm delivery in high risk women include the cerclage pessary and progesterone. Both of these interventions have been shown to effectively reduce the incidence of preterm birth in women with a short cervix. However, up until now, no study has directly compared the effectiveness of these two treatment options in women with twins. The purpose of this study is to directly compare the effectiveness of progesterone and cerclage pessaries in preventing preterm birth in women with a short cervix and twin pregnancy. Currently there is no standard treatment for short cervix in twin pregnancies. The standard treatment in singleton pregnancies is to offer progesterone. While the cerclage pessary is not widely used in Australia, it is widely used in Europe. A number of sites in Australia do use the cerclage pessary where they think it will be helpful.

This study is similar to a larger one currently being conducted in the Netherlands. We will be watching that study closely to see if any of it’s outcomes inform us regarding the conduct of this study here in South Australia.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 66978 0
Prof Ben Mol
Address 66978 0
The University of Adelaide
University Department of Obstetrics and Gynaecology,
Level I, Queen Victoria Building,
72 King William Rd.,
Country 66978 0
Phone 66978 0
+61 8 81617619
Fax 66978 0
Email 66978 0
Contact person for public queries
Name 66979 0
Dr Suzette Coat
Address 66979 0
Robinson Research Institute,
Level 3, 55 King William Rd.,
Country 66979 0
Phone 66979 0
+61 8 8313 1338
Fax 66979 0
Email 66979 0
Contact person for scientific queries
Name 66980 0
Prof Ben Mol
Address 66980 0
The University of Adelaide
University Department of Obstetrics and Gynaecology,
Level I, Queen Victoria Building,
72 King William Rd.,
Country 66980 0
Phone 66980 0
+61 8 8161 7619
Fax 66980 0
Email 66980 0

No information has been provided regarding IPD availability
Summary results
No Results