Condition category
Pregnancy and Childbirth
Date applied
22/09/2016
Date assigned
28/09/2016
Last edited
27/09/2016
Prospective/Retrospective
Retrospectively registered
Overall trial status
Ongoing
Recruitment status
Recruiting

Plain English Summary

Background and study aims
The length of a women’s cervix (cervical length) during pregnancy can affect the chances of premature labour. If a expectant mother has a short cervix, they can be at risk of going into premature labour and, therefore, premature birth of their baby. During pregnancy, the cervix (which is usually closed and rigid) with soften up over time, become shorter and open up as the baby grows and the body prepares to give birth. If the cervix begins to open too soon, premature birth may result. This study is looking at pregnant women with no symptoms pregnant with one baby, measuring the length of their cervix using vaginal ultrasound twice: at 18-20 weeks and at 21-23 weeks. The aims are to get an estimate of how many women have a short cervix during pregnancy, when it is best to measure the cervix to determine whether it is short, at what time is shortening of the cervix more likely to cause premature birth and how good the methods used to determine a short cervix are.

Who can participate?
Healthy pregnant women at between 18-20 weeks with one baby.

What does the study involve?
Participants have ultrasound examinations of their cervix at 18-20 weeks into their pregnancy and again at 21-23 weeks. At each session, the measurements are taken three times. The examination is carried out by a specially trained midwife. The women are not told the results of the measurements. Data is then collected to determine whether the method can successfully predict premature birth.

What are the possible benefits and risks of participating?
Not provided at time of registration

Where is the study run from?
Five hospitals in Sweden.

When is the study starting and how long is it expected to run for?
January 2014 to May 2017

Who is funding the study?
1. Swedish Research Council
2. Regional R & D Council, Uppsala / Örebro
3. Center for Clinical Research Dalarna
4. Southern Älvsborg Hospital
5. Regional R & D funds Västra Götaland
6. Hjalmar Svensson Research Fund
7. Löf (County Councils' Mutual Insurance)

Who is the main contact?
Dr Ulla-Britt Wennerholm
ulla-britt.wennerholm@vgregion.se

Trial website

http://www.medscinet.com/cervixstudien/

Contact information

Type

Scientific

Primary contact

Dr Ulla-Britt Wennerholm

ORCID ID

http://orcid.org/0000-0003-2475-2226

Contact details

Sahlgrenska Universitetssjukhuset
Östra
Göteborg
41685
Sweden
+46313435580
ulla-britt.wennerholm@vgregion.se

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

2014-10104-117089-114 The Swedish Research Council

Study information

Scientific title

Measurement of cervical length with vaginal ultrasound in the second trimester in asymptomatic women with a singleton pregnancy to predict preterm delivery: a Swedish multi-center observational study

Acronym

Study hypothesis

The general aim is to collect information to estimate if screening for preterm birth (PTB) with cervical length measurements at mid‐gestation using ultrasound and prophylactic progesterone treatment if the cervix is short is potentially cost‐effective in Sweden. The specific aims are to ‐ in a Swedish population:
1. Estimate the prevalence of ”short” cervix as measured by vaginal ultrasound at mid‐gestation in asymptomatic women with a singleton pregnancy
2. Find the optimal cervical length cutoff to predict PTB in asymptomatic women with a singleton pregnancy
3. Estimate the sensitivity and specificity with regard to PTB of ”short” cervix as measured by vaginal ultrasound (using different measurement techniques and definitions) at midgestation in asymptomatic women with a singleton pregnancy
4. Define the optimal gestational weeks (in the window from 18 to 23 gestational weeks) to measure cervical length to predict PTB in asymptomatic women with a singleton pregnancy
5. Investigate if a shortening of the cervix between gestational week 18‐20 and 21‐23 is more predictive of PTB than a single measurement of cervical length in asymptomatic women with a singleton pregnancy
6. Based on the results of 1., 2., 3., 4. and 5. and knowledge of the prevalence of PTB in singleton pregnancies in Sweden calculate the sample size of a Swedish randomized controlled trial to investigate the effect on PTB and neonatal outcome of screening asymptomatic women with a singleton pregnancy with ultrasound measurement of cervical length followed by progesterone treatment if the cervix is “short”

Ethics approval

Ethical committee at University of Gothenburg, Sweden, 13/11/2013 (ref: 825-13), 17/01/2014 (ref: T053-14), 08/12/2015 (ref: T972-15) and 25/02/2016 (ref: T122-16)

Study design

Multicentre prospective observational study

Primary study design

Observational

Secondary study design

Cohort study

Trial setting

Hospitals

Trial type

Screening

Patient information sheet

Condition

Pregnancy

Intervention

This is a Swedish multicentre prospective observational study. where healthy asymptomatic women with a singleton pregnancy will be examined with transvaginal ultrasound and measurement of cervical length during midtgestation.

Ultrasound examinations of the cervix are carried out by specially trained midwives, who have undergone standardized theoretical education and practical training. A certification system specially designed for this project is in place. The ultrasound examinations are performed vaginally with the woman in the lithotomy position with an empty urinary bladder. The vaginal ultrasound probe is slowly introduced into the vagina until the cervix becomes visible. Care is taken not to exert undue pressure on the cervix: the anterior and posterior lips of the cervix should appear equally thick. Ideally, the cervical canal should be horizontal in the image. The length of the closed cervical canal ( the line made by the interface of the mucosal surfaces) is measured as a straight line between the internal and external cervical os. If the isthmus is present its length is measured separately. Each measurement is taken three times, and all three are recorded. Images are stored for quality assessment.
These measurements are taken at 18+0-20+6 gestational weeks and 21+0-23+6 gestational weeks.

The women themselves and all medical staff are blinded to the results of the cervical length measurements. However, an ultrasound finding of bulging amniotic membranes is disclosed.

Intervention type

Procedure/Surgery

Phase

Drug names

Primary outcome measures

Ability of sonographic cervical length to predict preterm birth < 33 weeks, expressed as the area under the receiver operating characteristic curve (ROC) sensitivity, specificity, positive and negative likelhood ratio.

Secondary outcome measures

Ability of sonographic cervical length to predict spontaneous PTB < 33+0 gestational weeks and for total and spontaneous PTB <28+0, <29+0, <30+0, <31+0, <32+0, <34+0 and< 35+0 gestational weeks.

All calculations will be made for:
1. the length of the closed cervical canal
2. if the isthmus is present its length is measured separately
3. from the external cervical os to the apparent (virtual) inner cervical os (if isthmus is present)
4. the length of the closed cervical canal + the isthmus.

Each measurement is taken three times and all three are recorded. Calculations will be made for the minimum, maximum and mean value and separately for measurements taken at 18+0-20+6 gestational weeks and 21+0-23+6 gestational weeks. using the ROC curves, the optimal method for measuring cervical length (which week, which measurement) and the optimal cervical length cutoff of the optimal method to predict PTB will be identified. The ability of a change in cervical length between the first (at 18+0-20+6) and the second (at 21+0-23+6) cervical length measurement to predict PTB. The prevalence of "short cervix" (using different definitions) will be calculated.

Overall trial start date

01/01/2014

Overall trial end date

31/05/2017

Reason abandoned

Eligibility

Participant inclusion criteria

1. Asymptomatic women > 18 years old
2. With a live healthy singleton pregnancy in gestational week 18+0-20+6
3. Able to understand oral and written information

Participant type

Patient

Age group

Adult

Gender

Female

Target number of participants

11000

Participant exclusion criteria

1. Fetal malformation
2. Rupture of membranes
3. Current vaginal bleeding
4. Ongoing miscarriage
5. Cerclage in situ
6. Current progesterone treatment at the time of recruitment

Recruitment start date

01/05/2014

Recruitment end date

31/05/2017

Locations

Countries of recruitment

Sweden

Trial participating centre

Sahlgrenska University Hospital
Gothenburg
41685
Sweden

Trial participating centre

Skåne University Hospital
Malmö/Lund
20502
Sweden

Trial participating centre

Karolinska University Hospital Solna/Huddinge
Stockholm
17176
Sweden

Trial participating centre

Falun's Hospital
Falun
79182
Sweden

Trial participating centre

Örebro University Hospital
Örebro
70185
Sweden

Sponsor information

Organisation

Region Västra Götaland

Sponsor details

Regionens Hus
Vänersborg
46280
Sweden
+46104410000
regionenshus@vgregion.se

Sponsor type

Hospital/treatment centre

Website

http://www.vgregion.se

Funders

Funder type

Research council

Funder name

Swedish Research Council, Vetenskapsrådet

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

Regional R & D Council, Uppsala / Örebro (Regionala FOU rådet Uppsala/Örebro)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

Centrum fÖr Klinisk Forskning Dalarna

Alternative name(s)

Center for Clinical Research Dalarna, CKF

Funding Body Type

government organisation

Funding Body Subtype

government non-federal

Location

Sweden

Funder name

Southern Älvsborg Hospital (SÄS, Forskningsenhet)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

Regional R & D funds Västra Götaland (VGR Regionala FOU medel)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

Hjalmar Svensson Research Fund (Handlanden Hjalmar Svensson, Göteborg)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

Löf (County Councils' Mutual Insurance)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Results and Publications

Publication and dissemination plan

The results of the trial is expected to be presented during 2018 in scientific papers and at conferences.

Intention to publish date

01/06/2018

Participant level data

To be made available at a later date

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes