Condition category
Not Applicable
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Cervical dilatation is the term used to describe the opening of the cervix (entrance to the womb (uterus)). Cervical dilatation can occur naturally, such as during childbirth and miscarriage, or it can be caused by surgical or medical procedures, such as during a pregnancy termination (abortion). There are various mechanical devices available for surgeons or clinicians to use to open the cervix, however some of these devices carry a risk of causing complications, such as damage to the cervix or uterus. Hydraulic dilatation is an alternative method to open the cervix. This involves opening the cervix with a balloon placed within the cervix. Fluid is pumped into the balloon causing it to gently expand. The balloon’s expansion is controlled by a computer software system designed to provide continuous and controllable balloon dilatation (CCBD). The aim of this study is to test a new system for CCBD, which consists of a computer programmed hydrostatic pump connected to a balloon extension. This new CCBD method aims to measure and determine the strength of muscles within the cervix (cervical resistance), and also the location of cervical resistance, by placing two pressure-measuring films on the top and on the bottom of the balloon extension. This new system will be tested in women seeking a surgical abortion (vacuum aspiration).

Who can participate?
Pregnant women who have been pregnant for less than 10 weeks.

What does the study involve?
All participants have the new system for hydraulic dilatation during the abortion procedure.

What are the possible benefits and risks of participating?
The intervention is considered to be completely risk free and thus, beneficial for the patient.

Where is the study run from?
Clinical Center Kragujevac (Serbia)

When is the study starting and how long is it expected to run for?
May 2013 to September 2013

Who is funding the study?
Ministry of Education, Science and Technological Development (Serbia)

Who is the main contact?
Dr P Arsenijevic

Trial website

Contact information



Primary contact

Dr Petar Arsenijevic


Contact details

Mite Cenica 22

Additional identifiers

EudraCT number number

Protocol/serial number

III 41007

Study information

Scientific title

Analysis of cervical resistance during continuous controllable balloon dilatation


Study hypothesis

Cervical resistance during continuous controllable dilatation is highest in the zone of the internal orifice of the uterus (inner cervical os); the uterine cervix behaves as a sphincter during continuous controllable balloon dilatation.

Ethics approval

Ethics Committee of Clinical Center Kragujevac, Serbia, 16/04/2013, ref: 01-4169.

Study design

Prospective experimental randomised study

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet.


Cervical resistance during continuous controllable balloon dilatation prior to termination of unwanted pregnancy.


To measure and determine the location of cervical resistance: an improved system for continuous and controllable balloon dilatation (CCBD) (a programmed hydrostatic pump connected to a balloon extension) will be used. CCBD uses two pressure-measuring films on the top and on the bottom of the balloon extension. The dilation process is analysed using Dilation Controller software. The software monitors the dilation process in real time and controls the given mode of dilation.

Intervention type



Drug names

Primary outcome measure

To precisely measure, analyse and map the cervical canal during dilatation of the uterine cervix, and locate every point of resistance along the upper and lower sides of the cervical canal.

Secondary outcome measures

1. Association between values of cervical resistance and the number of previous miscarriages
2. Association between the values of cervical breaking point and number of previous miscarriages

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Age 18-40
2. Pregnancy verified by an ultrasound
3. Singleton pregnancy
4. Gestational age of 10 weeks or less
5. Absence of uterine bleeding or cramping
6. Cervix and uterus without pathological changes
7. Closed external cervical os

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Any previous attempt at an abortion or use of substances for cervical maturation
2. Multiple pregnancy
3. Presence or, at minimum, the suspicion of a septic abortion, followed by an elevated body temperature of 38°C or higher, uterine pain and odorous vaginal secretions.
4. Presence of any previous intervention performed on the uterine cervix
5. Uterine or cervical anomalies
6. Intrauterine device in situ
7. Hemorrhagic and/or chronic diseases

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Clinical Center Kragujevac
22 Zmaj Jovina Street

Sponsor information


Ministry of Education, Science and Technological Development (Serbia)

Sponsor details

Nemanjina street 22-26

Sponsor type




Funder type


Funder name

Ministry of Education, Science and Technological Development (Serbia)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

The results and conclusions of the study will be disseminated through scientific articles, scientific books, presentations and congress seminars. One article is about analysis of the cervical resistance measured by pressure sensitive films and is intended to be published by the end of this year. Another article is about sphincter qualities of the uterine cervix and is intended to be published by the end of this year.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

2015 results in:

Publication citations

Additional files

Editorial Notes