A Pilot Study of Cervical Stiffness Assessment With an Aspiration-based Device in High-risk Pregnancies for Preterm Birth
Conditions: Cervical Insufficiency, Cervical Stiffness
Sponsor: Luzerner Kantonsspital

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
1 
Project Title: 
A pilot study of cervical stiffness assessment with an 
 
 
 
aspiration-based device in high-risk pregnancies for  
 
 
 
preterm birth 
 
 
 
 
Research legislation: 
 Ordinance on human research with the exception of Clinical trials 
(HRO) [1]. 
 
 
Type of Research Project: 
Research project involving human subjects  
 
 
Risk Categorisation:  
Risk category A 
 
 
Sponsor 
 
 
 
 
 
 
 
 
 
Principal investigator  
 
 
 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
2 
PROTOCOL SIGNATURE FORM    
 
 
Study Title 
A pilot study of cervical stiffness assessment with an 
aspiration-based device in high-risk pregnancies for 
preterm birth 
  
 
The project leader has approved the protocol version 5, 7th October 2024 and confirms hereby to 
conduct the project according to the protocol, the Swiss legal requirements [1, 2], current version 
of the World Medical Association Declaration of Helsinki [3] and the principles and procedures for 
integrity in scientific research involving human beings.  
 
 
Sponsor:  
 
Principal investigator:  
 
 
 
 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
3 
GLOSSARY OF ABBREVATIONS 
 
BASEC 
Business Administration System for Ethical Committees 
CCI 
 
cervical consistency index 
CI 
 
cervical insufficiency 
CRF 
Case report form 
CI 
 
cervical insufficiency 
CSI 
 
cervical stiffness index 
EKZ 
Ethikkommission Zentralsschweiz 
FMF 
Fetal Medicine Foundation 
FOPH 
Federal Office of Public Health 
HRA 
Human Research Act 
HRO  
Ordinance on Human 
ICF  
 
Informed Consent Form 
PI  
 
Principal investigator 
PIS 
 
Patient Information Sheet 
PPROM 
preterm premature rupture of membranes  
PPS 
 
preterm parturition syndrom 
PTB   
preterm birth  
PTL 
 
preterm labour 
ROI 
 
region of interest 
Wp  
 
weeks of pregnancy 
 
 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
4 
1 
BACKGROUND AND PROJECT RATIONALE  
Preterm birth (PTB), defined by birth before 37th weeks of pregnancy (wp), is a public health 
concern and the most relevant risk factor for neonatal morbidity and mortality (4). The 
prevalence of PTB is between 5 to 9% in Europe. 40% occurs before 33 wp, whereas neonatal 
morbidity and mortality are related inversely to the gestational age (5). Despite advances in 
antenatal pregnancy care, the spontaneous preterm birth trend could not be reduced 
significantly in most countries except for black women (6, 7, 8). 
A combination of symptoms leading to PTB, summarized as the preterm parturition syndrome 
(PPS), involves multiple etiologies and pathological processes (6, 9, 10). Among those cervical 
insufficiency (CI) is a syndrome with a prevalence of around 1%, which is preterm cervical 
ripening without uterine contractility (9). Usually, recurrent pregnancy loss in the mid-trimester, 
bulging membranes without contractions, prior cervical surgery (conization, repeated cervical 
dilation associated with termination of pregnancy or missed abortions), or congenital cervical 
disorders (i.e., hypoplastic cervix, DES exposure in utero, congenital connective tissue disease) 
are related to cervical insufficiency (9, 11).  
Different interventions exist to reduce the preterm birth risk significantly. Vaginal progesterone 
use reduced the risk of recurrent preterm birth by up to 55% (12-18), even though the benefit 
was not equal for all women for reasons not well understood (12, 16, 17). Cerclage has been 
shown beneficial in pregnancies with a short cervix of less than 25 mm and a history of preterm 
birth in single pregnancies (12, 15) but stayed without benefit in low- or medium-risk 
pregnancies (19, 20). Neither cerclage nor progesterone was efficient in multiple pregnancies 
(21, 22). Nevertheless, the outcome was comparable for both interventions (15). Cervical 
pessary, introduced in the 1950s, showed some conflicting results in pregnancies with a cervical 
length less than 25 mm, while Goya et al. stated the benefit in reducing the preterm birth rate 
before 34 wp (23, 24, 25). 
 
However, prediction of CI in an ongoing pregnancy remains difficult unless there is a previous 
history of recurrent pregnancy loss in the mid-trimester or a history of extremely premature birth 
(10, 12). So far, cervical length measurement by ultrasound, which is inversely related to the 
risk of preterm birth, digital cervical assessment, and fibronectin testing are used to predict the 
preterm risk, but low sensitivities (sn < 40%) make them unsuitable as a screening test (12, 26, 
27). Concluding we need more accurate methods to estimate preterm birth risk. Therefore, 
recent research of the mechanical tissue property of the cervix may be promising, as cervical 
shortening is an equation between different forces and its mechanical property (28). Internal 
uterine pressure represents opening force pressure, whereas the lower abdomen or the pelvic 
floor represent external closing forces. The longitudinal deformation in the length of any material 
after applying a predefined pressure can be described by a percentage change in longitude or 
called a strain, which can be a positive or negative (tensile or compressive strain). The 
mechanical property of any material depends on the strain, the applied force, and the stressed 
area. This behavior can be visualized by stress-strain curves. So, either the mechanical 
pressure on a stiff cervix is significantly high, or the stiffness of the cervix is relevantly low to 
result in a cervical shortening. The cervical changes before, during, and after labor reflect its 
dynamic character. Collagen fibers degradation, distribution, cross-link density, organization, 
and composition of glycosaminoglycans explain this dynamic histologically (29, 30). So far, 
mechanical cervical behavior is analyzed by ultrasound, elastography, and an aspiration-based 
device.  
 
Cervical tissue deformability or cervical consistency index (CCI) was calculated using the 
percentage change of cervical length before and after applying manual pressure by a hand-held 
transvaginal ultrasound (31). This ratio showed a detection rate of spontaneous PTB of 100% 
before 32 wp decreasing to 79% before 37 wp, respectively, for a 10% screen-positive rate. The 
detection rate by only measuring the cervical length was less accurate, such as 33% and 26%, 
respectively, for a 10% screen-positive rate.  

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
5 
Elastography analyzes quantitative tissue deformability. Image analysis algorithms track many 
points at any time during the pushing and retracting of the hand-held ultrasound probe. 
Whereas a perfectly rigid organ would show a stable position of these points during motion, a 
soft organ would display broad changes in distance between the points, also called strain (28). 
Elastography assessments showed significant differences between cervical strains of women 
with PTB versus women with term birth (32-34).  A reduced cervical length or advanced 
gestational age was associated with higher strain (32-34). The lack of standardization of applied 
pressure or strain depending on different ROI stays a limitation of this methodology. Others 
used shear wave elastography which calculates strain using a high-frequency ultrasound pulse 
at a steady-state to avoid these limitations (35, 36). Significant differences in cervical elasticity 
in patients with high-risk factors for preterm birth and women who delivered preterm are found 
(35, 36).  
Another recent technique to reduce the mentioned constraints is an aspiration-based device, 
the Pregnolia System, which creates negative pressure to deform a tissue until a prespecified 
distance. The closing negative pressure (closing pressure or pcl) or the cervical stiffness index 
(CSI), is measured perpendicular at a specified region of the ectocervix, for instance at 12 
o’clock, at a tissue deformation of up to 4 mm. A lower CSI is associated with reduced stiffness 
(28). The intra-observer and inter-observer variability compared between CSI measurements of 
5 silicone cervix models were as high as 3.4 % (37). Digital palpation was unreliable (37). 
Different ROI of the cervix showed different standard deviations, whereas the smallest standard 
deviation was at 12 o’clock (38). CSI between non-pregnant and pregnant women or between 
the 1st and 2nd trimesters showed significant differences, but not between the 2nd and 3rd 
trimesters (38, 39). So far, 100 pregnant patients have not shown any adverse effects (pain, 
discomfort, bleeding) (38, 39) proving a low risk for use in clinical practice. Other ongoing 
studies including more than 1000 executed measurements have neither reported any serious 
adverse events related to the device according to the Pregnolia System provider 
(clinicaltrials.gov: NCT02037334; NCT05477381; NCT05267717; NCT05200117). One pilot 
study carried out on high-risk pregnant women showed significantly lower cervical stiffness in 
the history-indicated cerclage group compared with a low-risk control group (40). But so far, 
sparse data on high-risk patients is available.  
The current pilot investigation aims to assess cervical stiffness in women at high risk of 
premature birth who will be offered treatment with progesterone. According to international 
guidelines, a cervical length less or equal to 25 mm until the 24th wp is considered a high risk 
for preterm birth, and therefore progesterone treatment and close follow-up are initiated after 
ruling out other aetiologies for a short cervix such as contractions (41-44). In clinical practice, a 
cervical length inferior or equal to 25 mm is generally used until 34 wp as a cut-off for a more 
frequent follow-up to assess preterm birth risk. Nevertheless, the 5th centile is gestational age-
dependent and corresponds to a cervical length of 24,7 mm at 25 wp (45). Primarily we want to 
assess the cervical stiffness of pregnant women with a short cervix inferior to or equal to 25 mm 
before 32 wp and before the start of progesterone treatment. Secondarily we want to measure 
the effect of progesterone treatment on cervical stiffness during follow-up visits. For the 
assessment of the cervical stiffness, we will use the Pregnolia System (CE-marked device). 
2 
PROJECT OBJECTIVES AND DESIGN  
2.1 Hypothesis, primary and secondary objectives 
To date, no accurate prediction of preterm birth risk is possible. An aspiration-based device is a 
promising tool for measuring cervical stiffness index and possibly predicting outcomes. So far, 
sparse data on cervical stiffness in high-risk patients is available. Additionally, the effect of 
progesterone treatment on the mechanical cervical property is not well understood. We want to 
analyze cervical stiffness in patients with a short cervix £ 25 mm between 16weeks 0 days and 
32weeks 0 days of pregnancy before the initiation of progesterone treatment.  

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
6 
 
This study is an exploratory pilot study without any formal hypotheses. The aim is to obtain 
some data for an initial characterization of the distribution of the Cervical Stiffness Index (CSI) in 
the defined population of pregnant women with short cervix before initiation of progesterone 
treatment and within a month after start of progesterone treatment. 
This may serve as a basis for planning of larger studies in order to investigate the relationship 
between occurrence of cervical stiffness, course of cervical stiffness under progesterone 
treatment and the impact on birth and neonatal outcomes. 
Primary objective 
The primary objective is an initial characterization of the distribution of the median Cervical 
Stiffness Index (CSI, in mbar), corresponding to the median of three consecutive measurements 
at each presentation, at pregnant women of gestational age between 16weeks 0 days and 
32weeks 0 days with a cervical length £ 25 mm before the initiation of progesterone treatment. 
 
Secondary objectives 
- 
At each presentation three consecutive CSI measurements will be carried out and as a 
secondary objective the first, the highest, lowest and mean measurement will be 
analyzed for each secondary outcome.  
- 
Evaluate Cervical Stiffness Index 1, 2, 3 (CSI, in mbar) at follow-up visits on day 10-14 
and on day 24-28 after initiation of progesterone treatment, which is defined as day 1; 
further follow-up is not mandatory, but possible 
- 
Determine a first estimate of the correlation of the initial CSI and CSI changes with birth 
outcome (gestational age at birth) 
- 
Determine a first estimate of the correlation of CSI with cervical length (longer cervical 
length stiffer?) 
- 
Determine first signals for potential associations of CSI with additional treatments for 
preterm birth (tocolysis, cerclage, pessary) 
- 
Determine first signals for potential associations of CSI with neonatal outcome (birth 
weight, APGAR, arterial pH, admission to neonatal intensive care) 
- 
Safety objective: safety of the device, by assessing incidence, severity, and seriousness 
of device-related adverse events (discomfort, bleeding, lesion, irritation). 
 
2.2 Variables for primary and secondary endpoints 
Primary endpoint: Median Cervical stiffness Index (CSI, in mbar) measured before 
progesterone treatment start 
Secondary endpoints:  
- 
Cervical Stiffness Index 1, 2, 3 (first, max, min, mean) (CSI, in mbar) at follow-up visits 
- 
Cervical length at study entrance and during follow-up 
- 
Additional treatments during pregnancy (tocolysis, cerclage, pessary) 
- 
Birth outcome (gestational age at birth) 
- 
Neonatal outcome (birth weight, APGAR, arterial pH, admission to neonatal intensive 
care) 
- 
Safety outcome: Device-related adverse events, such as discomfort, bleeding, lesion, 
irritation or serious adverse events (incidence, severity, and seriousness). 
2.3 Project design 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
7 
A prospective, observational, non-interventional, post-market, single-center pilot study at the 
cantonal hospital of Lucerne will be carried out to answer the primary and secondary objectives. 
Patients presenting at or referred to our prenatal care will be included into this study.  
CSI measurements, general, clinical, laboratory, history and pregnancy data relevant for the 
study objectives will be collected and recorded under a unique study ID under which all data will 
be held in-line with the Data Protection Act in REDCap. Patient data corresponding to the study 
ID will be only known to the principal investigator and protected with a password on the hospital 
server.  
3 
PROJECT POPULATION AND STUDY PROCEDURES 
3.1 Project population, inclusion, and exclusion criteria  
Project population 
We are studying pregnant patients older then 18 years of age and pregnant between 16w0d 
and 37w0d. We estimate the number of patients with a short cervix inferior or equal to 25 mm 
(<5th centile at 25 wp) opting for a progesterone treatment around 10-20 at our center per year. 
For our pilot study we want to include 10 patients. After inclusion of the first 10 patients we want 
to continue our pilot study until latest June 2025. 
 
Inclusion criteria at study entry  
1. Informed consent signed by the participant 
2. Pregnant women ³ 18 years of age. 
3. Singleton gestation 
4. Weeks of pregnancy between 16 weeks 0 days and 32 weeks and 0 days 
5. Cervix £25 mm (inferior to the 5th centile at 25 wp according to Salomon et al. (45)) 
6. No regular contractions 
7. Planned progesterone treatment 
Exclusion criteria at study entry 
Any of the following criteria will lead to the exclusion of the subject: 
Cognitively impaired adults  
Cerclage or pessary on place 
Ongoing progesterone (if continued or started after 13+0 wp) treatment 
Multiple pregnancies 
Placenta praevia totalis with hemorrhage (irrespective of severity) 
Vasa praevia 
Light bleeding (if the bleeding can be stopped it is no longer an exclusion criterion) 
Heavy vaginal bleeding, hematoma or chorioamniotic membrane separation  
Rupture of membranes (exclusion with ROM+ test if PPROM is suspected) 
History of cervical surgery only if visible scaring at 12 o’clock 
Cervical dilation ³ 3 cm 
Signs of chorioamnionitis 
Symptomatic genital infection 
Known carrier of HIV or Hepatitis B/C 
Fetal malformations 
3.2 Recruitment, screening, and informed consent procedure 
Patients presenting with or referred to our unit for any reason with a finding of a cervix of £25  mm 
meeting the inclusion and excluding the exclusion criteria will be recruited to the study after 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
8 
informed consent is given. The same procedure can be also applied to patients presenting 
emergently and fulfilling the study criteria without delay if informed consent can be obtained. 
Patient recruitment is planned over a period of two years after study start.  
Study recruitment will only take place at our fetomaternal center. But referral doctors will be 
informed about the study purpose and procedure in case one of their patients meet the study 
criteria and has interest to participate. Written and oral informed consent will be taken from all 
patients agreeing with the study protocol by the principal investigator (PI) or an appropriate 
delegate. If time to consider study participation is needed, it will be respected. In that case 
medical treatment can be delayed upon the patient’s agreement by a few days usually without 
negative consequence, as treatment effect is based on its continuos use. No obligation for study 
participation and the possibility of later withdrawal without giving any reason will be explained to 
all participants. A copy of the signed Informed Consent Form (ICF) and the approved Patient 
Information Sheet (PIS) will be given to the study participant. The original signed and dated 
consent form will be retained in a study file after having been scanned into the electronic patient 
file. Study participation is voluntary, and no payment is planned for participation. Secondarily 
the Pregnolia probe and System will be offered for free to the study participants. 
3.3 Study procedures 
A short cervix £25 mm can occur any time in pregnancy. It can be a coincidental finding during 
routine check-ups, or a woman may be presenting with symptoms like for instance lower back 
or abdominal pain or vaginal pressure. A short cervix of £25 mm is a risk factor for preterm birth 
if diagnosed before 34 weeks of pregnancy. Therefore, in such situations we routinely assess 
the fetus and the placenta, and we carry out bacterial genital swabs, urinary and laboratory 
tests. Additionally in the study, we will measure the cervical stiffness index (CSI). The patient 
will be in lithotomy position; a typical gynecological examination position and a vaginal 
speculum will be inserted. After visualization of the anterior cervical lip the Pregnolia probe will 
be placed at 12 o’clock and a weak vacuum will be applied deforming the cervical tissue into the 
probe tip by a fixed distance of 4 mm. The vacuum needed to deform the cervical tissue inside 
the probe is a proxy value for the cervical stiffness, is expressed in mbar and is called Cervical 
Stiffness Index (CSI). The stiffer the cervical tissue, the higher the vacuum needed to deform it. 
The vacuum will be created three times at the same place giving three values before removing 
the probe and completing the examination. The three values will be noted into the patients’ file. 
An additional 5-10 minutes is calculated for this measurement during routine obstetric care. 
Details about the Pregnolia System can be also found under the following link: 
https://en.pregnolia.com/gebrauchsanweisung.  
The cervical length measurement will be carried out according to the criteria of the fetal medicine 
foundation (FMF London). All designees, the PI and the Sponsor will have been taught to use the 
Pregnolia System by the time of study start.  
If during follow-up there will be a need to apply a cervical cerclage or pessary, it will be discussed 
with the patient and applied without delay. A cerclage or pessary placement is a reason for 
exclusion from further follow-ups, as both may influence the cervical CSI. No disadvantage will 
arise for any patients by study participation or later withdrawal. The study will be carried out over 
a period of two years.  
 
Assessment schedule 
Enrolment 
 
Routine: 
Inform patient about study, purpose, risks, voluntary participation, the device, the right of 
withdrawal at any time and no disadvantages in case of study participation or 
disapproval 
Gather informed consent signature, thereafter, enroll subject into the study 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
9 
Demographic data (age, race) 
Chronic medical disease and obstetrical risk factors for preterm birth (gravidity, parity, 
D&C, cesarean, history of preterm birth or pregnancy loss > 12 wp, history of cervical 
conization) 
Reason for check-up (routine, symptoms at presentation) 
Gestational age at study enrolment 
Bacterial samples (yes/no, if yes which bacteria) 
Bacterial vaginosis (yes/no) 
Preexisting prematurity treatments (yes/no, if yes which treatment) 
Ultrasound-based measurement of cervical length 
 
Additional assessment for the study objectives: 
Acquire 3 consecutive CSI measurements with the Pregnolia System at 12 o’clock 
position on the squamous epithelium of the cervix, taking care to keep the probe tip in 
exactly the same position (study objective: first measurement; second and third 
measurement for documentation) 
Record day, hour, minute of the CSI measurement session 
Discomfort and side-effect assessment of the CSI measurement (taking care of 
distinguish between discomfort of the speculum insertion and of the measurement) 
Record adverse events (discomfort, bleeding, lesion, irritation) or if measurement is not 
possible and the reason for it 
Record remarks. 
 
Follow-up 
 
Routine 
At least two follow-up visits every 10-14 days, further follow-ups are optional 
Record obstetrical data if anything new arrives (hospitalization, tocolytics, lung 
maturation, cerclage, pessary) 
Speculum examination and CSI measurement 
Ultrasound measurement of cervical length 
 
Additional assessment for the study objectives: 
Acquire 3 consecutive CSI measurements with the Pregnolia System at 12 o’clock 
position on the squamous epithelium of the cervix, taking care to keep the probe tip in 
exactly the same position 
Record day, hour, minute of the CSI measurement session 
Discomfort and side-effect assessment of the CSI measurement (taking care of 
distinguish between discomfort of the speculum insertion and of the measurement) 
Record adverse events (discomfort, bleeding, lesion, irritation) or if measurement is not 
possible and the reason for it 
Record remarks. 
 
Postpartum (data collection in absence of the participant)  
 
Check and record other interventions and/or treatments if occurred during pregnancy 
and at birth (hospitalization, tocolytics, lung maturation, cerclage, pessary) 
Delivery information (GA at delivery) 
Newborn data and morbidities (APGAR, pH, weight, admission to NICU during the first 7 
days) 
Record adverse events (discomfort, bleeding, lesion, irritation) 
Record remarks. 
 
Graphical assessment schedule 
 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
10 
Time (days) 
0 
+10-
14 
+24-
28 
(+38-42) (+xx-xx) postpartum 
Visit 
Study 
inclusion  
1st 
follow-
up 
2nd 
follow-
up 
Optional 
3rd 
follow-
up 
Optional 
further 
follow-
up 
In absence 
of 
the 
patient 
oral and written 
Information 
+ 
 
 
 
 
 
Written consent 
+ 
 
 
 
 
 
inclusion-/ 
exclusion 
criteria 
+ 
 
 
 
 
 
 
 
 
 
 
 
 
Demograophic 
data 
+ 
 
 
 
 
 
Medical data 
+ 
 
 
 
 
 
 
 
 
Obstetric data 
+ 
 
 
 
 
 
Study 
withdrawal 
or 
discontinuation 
(+) 
 
(+) 
(+) 
 
(+) 
 
(+) 
 
(+) 
Clinical 
exam 
and 
CSI 
measurement 
+ 
 
+ 
+ 
 
(+) 
 
(+) 
 
Safety outcome 
+ 
+ 
+ 
+ 
+ 
 
Laboratory 
results 
+ 
 
+ 
 
+ 
 
+ 
 
 
+ 
 
 
Treatments 
+ 
+ 
+ 
(+) 
(+) 
 
Birth data 
 
 
 
 
 
+ 
Neonatal data 
 
 
 
 
 
+ 
Remarks 
+ 
+ 
+ 
+ 
+ 
+ 
3.4 Withdrawal and discontinuation 
If a patient withdraws informed consent she will be excluded from the further study, which will be 
indicated in the CRF. Data which has been collected until that moment will be utilized.  
Another reason for discontinuation from further measurement follow-ups is an increasing 
shortening of the cervical length requiring additional treatments with a pessary or a cerclage due 
to treatment change, which makes CSI comparison no longer possible. Discontinuation applies 
also in case of a PPROM or in case of repetitive, strong bleedings of the utero-placental interface. 
Furthermore, a very short or soft cervix might make the CSI measurement impossible, or the 
specular examination might be undesirably uncomfortable which are other reasons of 
discontinuation. In these cases, all data will be used. The latter reasons or if examination is 
impossible will be noted as a remark and will be mentioned in the final analysis.  
3.5 Identification and description of the medical device for cervical stiffness measurement  
Pregnolia System, composed of the Pregnolia Control Unit (REF 100058) and Pregnolia Probe 
(REF 100026). 
Manufacturer: Pregnolia AG, Wiesenstrasse 33, 8952 Schlieren, Switzerland 
The device is composed of a single-use sterile probe and a reusable control unit. The Pregnolia 
System is designed for use in a gynaecological examination room 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
11 
equipped for speculum-based vaginal examinations.  
Description of use see paragraph 3.3. 
See instructions for use:  
https://en.pregnolia.com/gebrauchsanweisung 
Labelling, supply (re-SUPPLY) and storage conditions 
Pregnolia is a CE certified device, which has been manufactured and labelled in accordance 
with the applicable Swiss and European requirements, including but not limited to the MDR or 
MDD (which ever applies), ISO 13485:2016 and Good Manufacturing Practice Guidelines 
(GMP) in their current version.  
Upon delivery of the the reusable control unit and the single-use sterile probes they will be 
identified and stored in a board in our outpatient prenatal clinic disposable only for the purpose of 
this study. If stored in a board then there is no special requirement for the storage. The device 
remains in the sole property of Pregnolia. The Device will only be used in the manner intended 
and only as described in written directions provided by the manufacturer Pregnolia AG.  
Accountability of the Pregnolia device 
The key for the locker, where the Pregnolia is stored will be available for the team of the prenatal 
outpatient clinic. All designees will get appropriately instructed about the protocol and how to use 
the Pregnolia unit only defined for use in this study. Every use will be recorded on a 
documentation sheet next to the Pregnolia device storage. Additionally, the LOT number of the 
Pregnolia probe will be documented for each patient in their file. 
We will promptly notify Pregnolia upon becoming aware of the need for Device maintenance or 
repair with appropriate care within the littlest delay. The serial number, any date of reception, use, 
return or repair of the device will be documented on a documentation sheet located in the storage 
next to the Pregnolia device, which will be checked by the PI regularly.  
Return of the device 
At the completion of the Investigation the Institution will return to Pregnolia, the Device and all 
related materials. In case of any deficiency including malfunction, usability issues, or inadequacy 
in the information supplied by the manufacturer Pregnolia AG will be notified in the shortest delay.  
4 
STATISTICS AND METHODOLOGY 
4.1. Statistical analysis plan 
In this pilot study, 10 (an estimated 20 subjects after continuation of the study) subjects will be 
included for the analysis of the pilot study. We chose 10 (to around 20) subjects because it is a 
feasible number to recruit and is supposed to sufficiently support to exploratory aim to obtain 
some data for an initial characterization of the distribution of the Cervical Stiffness Index (CSI) 
and to receive feedback on how the investigation is perceived in the defined population of 
pregnant women. As recruitment has progressed, we would like to continue to recruit more 
subjects to broaden the initial data base meanwhile we will evaluate the so far collected data. 
The Cervical Stiffness Index (CSI) is a continuous variable. Quantitative parameters will be 
described in terms of absolute values and changes from baseline by time point. Descriptive 
statistics will comprise median, interquartile range, minimum and maximum, mean and standard 
deviation and, where appropriate (especially for changes from baseline), 95% confidence 
intervals for the mean or median. 
Qualitative parameters will be analysed utilizing frequency tables by time point and treatment.  
Scatterplots or Box Plots may be used to visualize associations of CSI with some of the secondary 
endpoints. Evaluation of potential associations by measures of association or correlation 
coefficients will be purely exploratory.  

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
12 
4.2. Handling of missing data  
The number of subjects who completed the study and discontinued from the study will be 
provided. A participant who will withdraw from the study will be asked for her reason and questions 
will be answered if desired. She has the right to withdraw without giving any reasons. As far as 
the reasons for study withdrawal are known they will be presented. 
All available data will be included in the analysis and will be used to the largest possible extent. 
Missing data will not be imputed for the descriptive and exploratory evaluations. However, the 
potential impact of missing values will be discussed when the study is reported. If deemed 
necessary, sensitivity analyses will be performed. 
5 
REGULATORY ASPECTS AND SAFETY 
5.1 Local regulations / Declaration of Helsinki 
This research project will be conducted in accordance with the protocol, the Declaration of 
Helsinki [3], the principles of Good Clinical Practice, the Human Research Act (HRA) and the 
Human Research Ordinance (HRO) [1] as well as other locally relevant regulations. The Project 
Leader and the Sponsor acknowledge their due responsibilities. 
5.2 Notification of safety and protective measures (HRA Art. 15, HRO Art. 20) 
If, during the research project, circumstances arise which could jeopardise the safety or health of 
the participants or lead to a disproportionate relationship between the risks and burdens and the 
benefits, all the measures required to ensure protection are to be taken without delay. 
The project leader and the sponsor are promptly notified (within 24 hours) if immediate safety and 
protective measures have to be taken during the conduct of the research project. The Ethics 
Committee will be notified via BASEC of these measures and of the circumstances necessitating 
them within 7 days. 
5.3 Serious events (HRO Art. 21) 
If a serious event occurs, the research project will be interrupted, and the Ethics Committee will 
be notified on the circumstances via BASEC within 7 days according to HRO Art. 211. Therefore, 
the template to report safety events to the Ethics Committee on the swissethics webpage will be 
used (www.swissethics.ch).  
5.4 Procedure for investigations involving radiation sources 
Not applicable.  
5.5 Amendments 
As recruitment progresses, it will be evaluated whether an amendment to the clinical investigation 
plan is feasible and appropriate. Substantial changes to the project set-up, the protocol and 
relevant project documents will be submitted to the Ethics Committee for approval according to 
HRO Art. 18 before implementation. Exceptions are measures that have to be taken immediately 
in order to protect the participants.  
 
1 A serious event is defined as any adverse event where it cannot be excluded, that the event is attributable to the 
sampling of biological material or the collection of health-related personal data, and which: 
a. requires inpatient treatment not envisaged in the protocol or extends a current hospital stay; 
b. results in permanent or significant incapacity or disability; or 
c. is life-threatening or results in death. 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
13 
5.6 End of project 
Upon project completion or discontinuation, the Ethics Committee will be notified within 90 days.  
Details about the storage of the study data are in paragraph 7.4. 
5.7 Insurance 
In the event of project-related damage or injuries, the Sponsor will be liable, except for damages 
that are only slight and temporary; and for which the extent of the damage is no greater than 
would be expected in the current state of scientific knowledge (Art. 12 HRO). As there is no 
specific need of a liability guarantee in this HRO study category A and the sponsor is working at 
the hospital, the hospital liability insurance is covering any damage or injuries if needed. 
6 
FURTHER ASPECTS 
6.1 Overall ethical considerations 
Measuring cervical stiffness is a promising recent method with a potential of closing the gap of 
predicting premature risk. Exploring data in low-risk populations exist and cervical stiffness 
measurement with the Pregnolia System is already offered at certain obstetrical offices and will 
be also offered in little time in our hospital on demand and self-cost of the patient (outside of the 
study protocol; some complementary insurances pay the costs), but data for best use in clinical 
practice is still missing. We need to have a deeper understanding to establish it in routine clinical 
care. We chose an observational study design to further increase knowledge in high-risk 
populations and finally open the floor for randomized clinical trials. The Pregnolia System has 
already been used in over 1000 pregnancies without considerable adverse events. Participation 
is voluntarily and examination is done during routine clinical care in patients already at risk for 
preterm birth with a possible desire to use this device and to improve clinical care for future 
pregnancies.  
6.2 Risk-Benefit Assessment 
Considering the exclusion criteria for study inclusion potential risks are minimized and will not 
differ substantially from routine clinical practice. High-risk patients for preterm birth may benefit 
from additional assessment of cervical stiffness, but main benefit will be reserved for future 
pregnancies such as the accuracy of the prediction of risk for prematurity and therefor decisions 
about the frequency of follow-up or therapy. 
The cervical stiffness measurement is done with the Pregnolia System. It has been CE-marked 
by TÜV Süd. Part of the registration process included a risk-benefit analysis according to ISO 
14971 of the Pregnolia System. 
Careful application of the Pregnolia System according to the instructions for use should result in 
minimal risks for the patients. The instructions for Use can be found under the following link: 
https://en.pregnolia.com/gebrauchsanweisung.  
Potentially, an irritation and sensitization of the mucosal tissue may happen. This may result in a 
spotting or a light bleeding, which can be easily treated by applying a light pressure with a soft 
swab. Light, self-limiting bleedings can be also caused by specula insertion or by manual 
palpation exams during usual obstetric or gynecological care. Besides, we will assess the 
discomfort and the side-effects after each measurement check-up. All possible complications and 
side-effects can be also found in the Instructions for Use.  
The use of the Pregnolia System as specified in the Instructions for Use reduces the risk of 
potential complications. All doctors and designees will have received appropriate instructions for 
use before study start.  

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
14 
6.3 Rationale for the inclusion of vulnerable participants  
Indeed, pregnant patients at risk for preterm birth have generally a certain vulnerability due to 
their clinical findings but our staff is trained to answer the demands of our patients. Additionally, 
the study aims to offer specifically patients at risk for preterm birth an improved prediction in the 
future.  
Patient recruitment will only start after EKNZ has given study approval. The study protocol and 
the pseudonymous data storage will be explained to all eligible pregnant patients, who wish to 
enter the study. The study recruitment, screening and informed consent procedure is explained 
in chapter 3.2.   
7 
QUALITY CONTROL AND DATA PROTECTION 
7.1 Quality measures  
All designees and the principal investigator will be trained to do cervical stiffness measurements 
if no previous traning has been conducted. CSI measurements will be noted on a CSI 
documentation form, which is an additional template to the ICF, and will be scanned into the 
patient’s file after every visit.  
Additionally, the electronic data capture (EDC) system REDCap will be used in this study, a 
secure web application for building and managing online surveys and databases. The EDC 
system REDCap is accessible via Webbrowser over the internet. Two-factor authentication 
(Username, Password, Softtoken) is needed to access the EDC system (except for internal 
access 
no 
softtoken 
is 
needed).  
The EDC System runs on the servers from LUKS (no cloud), which are in two datacenters 
(failover) near Lucerne. The servers are operated and monitored by the IT department of the 
LUKS. Every hour a back-up of the study data will be done. The user privileges in the EDC system 
are set on project level (access) and can be granular set / modified in the project. So, it can be 
ensured that only authorized persons can enter the system to view, enter, edit, or release data 
according to their permissions. An audit trail documents all entries and changes made in the 
system and by whom. The project set-up and eCRFs will be tested by (the PI and the 
sponsor) prior to the release into the productive environment. Furthermore, specific training for 
the use of REDCap will be provided. Plausibility rules and range-checks will be established to 
promote data quality. Furthermore, data will be reviewed and verified on a risk-based approach 
prior to data entry completion. 
For quality assurance the Ethics Committee may visit the research sites. Direct access to the 
source data and all project related files and documents must be granted on such occasions. 
7.2 Data recording and source data 
Data recording is already described above. Basically, all data recordings will exist on the patient 
file which will be transferred to REDCap by the PI. Only the following persons will get access to 
the EDC system REDCap: the PI (writing and reading permission) and the Sponsor (writing 
permission on demand, reading permission). The database set up will be prepared by the PI 
and tested by the sponsor and or other medical leading staff of the women’s department. The 
data entry, monitoring and data release will be done by the PI. Nevertheless, the sponsor may 
be involved any time.  
Data will first be collected using electronic patient chart. All data is then transferred into the EDC 
system REDCap by the PI. CRFs and data entries will be kept current to reflect subject status at 
each phase during the course of study. 
7.3 Confidentiality and coding 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
15 
Project data will be handled with uttermost discretion and is only accessible to authorized 
personnel who require the data to fulfil their duties within the scope of the research project.  
Study participants will not be identified in the CRF by name or initials or birth date. Instead, an 
encrypted identification number (code) will be used. Encrypted data will be exported from the 
EDC system by the study personal for analysis in statistic software. 
For 
each 
enrolled 
study 
participant, 
an 
eCRF 
is 
maintained. 
The patient identification list, which contains the person-identifying data (e.g., name) of each 
patient along with the assigned unique identifying number is stored on the hospital server under 
the password only known to the PI. This folder Data is only accessible to the study personnel 
according to their level of authorization. The PI, the sponsor, the medical chiefs of the women’s 
department will have access to all data on demand whereas the statistician or research staff will 
only have access to encrypted data. 
7.4 Retention and destruction of study data 
The data will not be anonymized after statistical analysis. Electronic study data are archived in 
an encrypted form for a minimum of 10 years after study termination or premature termination of 
the clinical trial in an electronic archive maintained and controlled by the IT department of 
LUKS. 
Source data and identification list will be stored in a locked archive room with limited access for 
a minimum of 10 years. 
8  FUNDING / PUBLICATION / DECLARATION OF INTEREST 
All study materials and procedures are part of routine clinical care in patients with a risk of preterm 
birth except the Pregnolia System, which will be provided by the Pregnolia company. The written 
contract with the Pregnolia company can be found attached to this protocol.  
All contributors to the study have no conflict of interest to declare and there is no financial interest 
to report.   
9 
REFERENCES 
 
1. 
Ordinance on Human Research with the Exception of Clinical trials (HRO) 
https://www.admin.ch/opc/en/classified-compilation/20121177/index.html  
2. 
Human Research Act (HRA) 
http://www.admin.ch/opc/en/classified-
compilation/20121176/201401010000/810.305.pdf  
3. 
Declaration of Helsinki  
(https://www.wma.net/policies-post/wma-declaration-of-helsinki-ethical-principles-
for-medical-research-involving-human-subjects ) 
4. Statistik der Todesursachen und Totgeburten von 1995 bis 2018 in der Schweiz. BFS-Nr.: 
je-d-
14.03.04.01.10.https://www.bfs.admin.ch/bfs/de/home/statistiken/gesundheit/gesundheitszu
stand/sterblichkeit-todesursachen/saeuglings-totgeburten.assetdetail.14966028.html. 
Bundesamt für Statistik. Published 14.12.2020. 
5. Goldenberg, R. L., et al. (2008). "Epidemiology and causes of preterm birth." The Lancet 
371(9606): 75-84. 
6. Zeitlin, J., et al. (2013). "Preterm birth time trends in Europe: a study of 19 countries." 
BJOG: An International Journal of Obstetrics & Gynaecology 120(11): 1356-1365. 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
16 
7. Ananth, C. V., et al. (2005). "Trends in Preterm Birth and Perinatal Mortality Among 
Singletons: United States, 1989 Through 2000." Obstetrics & Gynecology 105(5 Part 1). 
8. Romero, R., Espinoza, J., Kusanovic, J., Gotsch, F., Hassan, S., Erez, O., Chaiworapongsa, 
T. and Mazor, M. (2006), The preterm parturition syndrome. BJOG: An International Journal 
of Obstetrics & Gynaecology, 113: 17-42. 
9. Brown, R., Gagnon, R., & Delisle, M. F. (2019). "No. 373-Cervical Insufficiency and Cervical 
Cerclage." JOGC, 41(2), 233–247. 
10. Gotsch, F., et al. (2009). "The preterm parturition syndrome and its implications for 
understanding the biology, risk assessment, diagnosis, treatment and prevention of preterm 
birth." The Journal of Maternal-Fetal & Neonatal Medicine 22(sup2): 5-23. 
11. Romero, R., et al. (2006). "The role of cervical cerclage in obstetric practice: can the patient 
who could benefit from this procedure be identified?" American journal of obstetrics and 
gynecology 194(1): 1-9. 
12. Iams, J. D., et al. (2008). "Primary, secondary, and tertiary interventions to reduce the 
morbidity and mortality of preterm birth." The Lancet 371(9607): 164-175. 
13. Dodd, J. M., et al. (2013). "Prenatal administration of progesterone for preventing preterm 
birth in women considered to be at risk of preterm birth." Cochrane Database of Systematic 
Reviews. 
14. Romero, R., et al. (2012). "Vaginal progesterone in women with an asymptomatic 
sonographic short cervix in the midtrimester decreases preterm delivery and neonatal 
morbidity: a systematic review and metaanalysis of individual patient data." American 
Journal of Obstetrics & Gynecology 206(2): 124.e121-124.e119. 
15. Conde-Agudelo, A., et al. (2013). "Vaginal progesterone vs cervical cerclage for the 
prevention of preterm birth in women with a sonographic short cervix, previous preterm birth, 
and singleton gestation: a systematic review and indirect comparison metaanalysis." 
American Journal of Obstetrics & Gynecology 208(1): 42.e41-42.e18. 
16. Dodd, J. M., et al. (2013). "Prenatal administration of progesterone for preventing preterm 
birth in women considered to be at risk of preterm birth." Cochrane Database of Systematic 
Reviews. 
17. Romero, R., et al. (2012). "Vaginal progesterone in women with an asymptomatic 
sonographic short cervix in the midtrimester decreases preterm delivery and neonatal 
morbidity: a systematic review and metaanalysis of individual patient data." American 
Journal of Obstetrics & Gynecology 206(2): 124.e121-124.e119. 
18. Dodd, J. M., et al. (2013). "Prenatal administration of progesterone for preventing preterm 
birth in women considered to be at risk of preterm birth." Cochrane Database of Systematic 
Reviews.  
19. Alfirevic, Z., et al. (2017). "Cervical stitch (cerclage) for preventing preterm birth in singleton 
pregnancy." Cochrane Database of Systematic Reviews. 
20. Drakeley, A. J., et al. (2003). "Cervical stitch (cerclage) for preventing pregnancy loss in 
women." Cochrane Database of Systematic Reviews. 
21. Rafael, T. J., et al. (2014). "Cervical stitch (cerclage) for preventing preterm birth in multiple 
pregnancy." Cochrane Database of Systematic Reviews(9). 
22. Dodd, J. M., et al. (2019). "Prenatal administration of progestogens for preventing 
spontaneous preterm birth in women with a multiple pregnancy." Cochrane Database of 
Systematic Reviews(11). 
23. Abdel-Aleem, H., et al. (2013). "Cervical pessary for preventing preterm birth." Cochrane 
Database of Systematic Reviews(5). 
24. Goya, M., et al. (2012). "Cervical pessary in pregnant women with a short cervix (PECEP): 
an open-label randomised controlled trial." The Lancet 379(9828): 1800-1806. 
25. Nicolaides, K. H., et al. (2016). "A Randomized Trial of a Cervical Pessary to Prevent 
Preterm Singleton Birth." New England Journal of Medicine 374(11): 1044-1052. 

 
 
CervicalStiffnessProgesterone, Protocol, Luzern, V5.0, 07.10.2024 
 
 
17 
26. Berghella V, Saccone G. Cervical assessment by ultrasound for preventing preterm 
delifvery. Cochrane Database of Systematic Reviews 2019, Issue 9. Art. No.: CD007235. 
DOI: 10.1002/14651858.CD007235.pub4. Accessed 20 July 2021 
27. Carr-Hill, R. A. and M. H. Hall (1985). "The repetition of spontaneous preterm labour." 
BJOG: An International Journal of Obstetrics & Gynaecology 92(9): 921-928. 
28. Mazza, E., et al. (2014). "In vivo assessment of the biomechanical properties of the uterine 
cervix in pregnancy." Prenatal Diagnosis 34(1): 33-41. 
29. Petersen, L. K. and N. Uldbjerg (1996). "Cervical collagen in non-pregnant women with 
previous cervical incompetence." European Journal of Obstetrics and Gynecology and 
Reproductive Biology 67(1): 41-45. 
30. Timmons, B., et al. (2010). "Cervical remodeling during pregnancy and parturition." Trends 
in endocrinology and metabolism: TEM 21(6): 353-361. 
31. Paara-Saavedra, M., et al. (2011). Prediction of preterm birth using the cervical consistency 
index. UOG. 
32. Hernandez-Andrade, E., et al. (2013). Evaluation of cervical stiffness during pregnancy 
using semiquantitative ultrasound elastography. UOG. 
33. Du, L., et al. (2019). Evaluation of cervical elastography for prediction of spontaneous 
preterm birth in low-risk women: A prospective study. J Ultra Med 
34. Gesthuysen, A., et al. (2019). Evaluation of cervical elastography strain pattern to predict 
preterm birth. 
35. Nazzaro, G., et al. (2020). Cervical elastography using E-cervix for prediction of preterm 
birth in singleton pregnancies with threatened preterm labor.  
36. Patberg, E. T., et al. (2021). Use of cervical elastography at 18 to 22 weeks’ gestation in the 
preterm birth.  
37. Badir, S., et al. (2020). "Aspiration technique-based device is more reliable in cervical 
stiffness assessment than digital palpation." BMC Pregnancy and Childbirth 20(1): 391. 
38. Badir, S., et al. (2013). "A novel procedure for the mechanical characterization of the uterine 
cervix during pregnancy." Journal of the Mechanical Behavior of Biomedical Materials 27: 
143-153. 
39. Badir, S., et al. (2013). "Cervical softening occurs early in pregnancy: characterization of 
cervical stiffness in 100 healthy women using the aspiration technique." Prenatal Diagnosis 
33(8): 737-741. 
40. Poster 213 Assessment of cervical stiffness in cervical insufficiency using a novel aspiration-
based device. Julie M. Stone, Michael House. Tufts Medical Center, Boston, MA. American 
Journal of Obstetrics and Gynecology Supplement to February 2021, p142 
41. Coutinho CM, Sotiriadis A, Odibo A, Khalil A, D’Antonio F, Feltovich H, Salomon LJ, 
Sheehan P, Napolitano R, Berghella V, da Silva Costa F, on behalf of the ISUOG Clinical 
Standards Committee. ISUOG Practice Guidelines: role of ultrasound in the prediction of 
spontaneous preterm birth. Ultrasound Obstet Gynecol 2022; 60: 435 – 456.  
42. Preterm labour and birth, NICE guideline, published: 20 November 2015, 
www.nice.org.uk/guidance/ng25 
43. AWFM Leitlinie, Registernummer 015-025, Leitlinienklasse S2k, Stand Februar 2020, 
Version 1.1, Prävention und Therapie der Frühgeburt, DGGG 
44. Jacobsen, B, et al. FIGO good practice recommendations for reducing preterm birth and 
improved child outcomes. Int J Gynecol Obstet. 2021; 155:1-4. 
45. Salomon, J., et al. (2009). Reference range for cervical length throughout pregnancy:non-
parametric LMS-based model applied to a large sample. UOG.