Clinical guide to reading cervical elastography output: stiffness index values, colour mapping and thresholds for threatened preterm labour and induction readin
Clinicians looking to understand cervical length measurement thresholds and how cervicometry fits into preterm birth risk stratification protocols.
Clinical guide to threatened preterm labor: diagnostic criteria, cervical assessment, biomarkers, bed rest evidence, and hospital vs. outpatient management path
Cervical biomechanics assessment for obstetric teams: anatomical measurement limits, an elastography bridge, and instrumentation procurement criteria.
Preterm birth clinical presentation, gestational classification and week-by-week neonatal outcomes: a reference for obstetric teams on risk stratification.
Why the Bishop Score falls short for induction readiness and how torsional wave elastography delivers objective, operator-independent cervical assessment.
Cervical assessment in obstetrics still relies on tools that only capture part of the picture: a manual exam, a length measurement, a biomarker test. None of them tells a clinician how the tissue itself is behaving mechanically, information that matters for predicting preterm birth and induction outcomes alike. Shear wave elastography (SWE) has emerged as an answer to that gap, and this article walks through the physics behind it, where the clinical evidence stands, and what to look for when evaluating an SWE-capable device for your department. What Is Shear Wave Elastography? Principles and How It Differs from Strain Elastography Elastography quantifies how a tissue responds to a mechanical stimulus: softer tissue deforms more easily than firm tissue, and this contrast translates into a stiffness value. The technique branches into two families depending on how that impulse is generated. Strain elastography measures tissue displacement under manual probe compression and renders the result as a color-coded map. It is intuitive and low-cost, but cannot report an absolute stiffness value, only a relative one, since the cervix has no adjacent reference tissue to compare against. Conventional shear wave elastography uses an ultrasonic push to generate the impulse and measures the speed of the resulting shear wave as it travels through tissue. A focused ultrasound beam displaces the tissue at a single point, generating a shear wave that propagates perpendicular to the beam’s direction. Because this wave travels through stiff tissue far faster than through soft tissue, the system builds a real-time color map of that speed across the image — soft areas in blue, stiff areas in red. Placing a region of interest on that map returns a quantitative stiffness value, expressed as shear wave velocity (m/s) or Young’s modulus (kPa) depending on the system. Clinical Applications of SWE in Obstetric Practice Cervical stiffness assessment for preterm birth risk stratification Although the Bishop score has been a widely used digital examination of the cervix for decades, it is now used less often because it is too invasive and subjective. Transvaginal ultrasound measurement of cervical length (CL) and detection of fetal fibronectin in cervicovaginal secretions remain the standard approaches for assessing preterm birth risk. These techniques account for false-positive rates of 70 and 75%, respectively, leading to unnecessary hospitalizations, tocolytics administration, healthcare costs, and waste of resources. Up to 60% of spontaneous preterm births occur in women with normal CL. A cervix can stay anatomically long while the internal os, the region responsible for maintaining pregnancy, is already softening beneath the surface. Because the internal os cannot be assessed manually, elastography is the only tool that reaches it and gives information about the biomechanical state of the cervix. Studies assessing internal os stiffness using strain elastography in low-risk populations at 18–22 weeks found that a soft internal os was associated with substantially higher rates of subsequent preterm delivery than a firm one, with figures as high as 81.1% versus 1.7% in one prospective cohort (Wozniak et al., 2014). Shear wave measurements in the prediction of preterm labor were reported for the first time in 2015. Shear wave speed specifically correlates with gestational age, with the presence of preterm contractions, and with the risk of preterm delivery (Muller et al., 2015), reinforcing the case for combining stiffness data with cervical length rather than relying on length alone. A 2025 systematic review and meta-analysis pooling 13 studies and 4,087 women confirms this predictive value for preterm birth: cervical elastography correctly flagged roughly three out of every four women who ultimately delivered preterm (Angelopoulou et al., 2025). SWE showed higher sensitivity later in gestation, and strain elastography performed comparatively better earlier on. Induction readiness: complementing and replacing the Bishop Score The Bishop score was developed on a cohort of multiparous women with prior vaginal deliveries, using induction methods that bear little resemblance to today’s balloon catheters and staged prostaglandin protocols. It is now applied indiscriminately to nulliparous women, whom Bishop explicitly excluded. The ARRIVE trial found no significant reduction in cesarean risk by Bishop score subgroup among nulliparous women induced at 39 weeks, an unexpected result given decades of assumed correlation (Grobman et al., 2018). Elastography has consistently outperformed the Bishop score on this question. A 2016 meta-analysis pooling four studies and 323 women found cervical elastography superior to the Bishop score for predicting labor induction success (Londero et al., 2016). In a prospective study of 475 women undergoing induction, cervical SWE measured across the inner, middle, and outer regions of the cervix is a useful predictor of cesarean section. The combination of sonographic cervical length and elastography is superior to the Bishop score in the prediction of the outcome of labor induction (Lu et al., 2020). How to Select a Shear Wave Elastography-Capable Device for Your Department Conventional shear wave elastography has real limitations. Because shear waves lose strength quickly as they travel, the technique works best on tissue close to the probe and becomes less reliable at depth. It’s also sensitive to how the tissue is being handled: pressing the probe too firmly can artificially stiffen the reading before the measurement even starts. And because different systems use different scanning parameters, results aren’t always directly comparable from one machine to another. Although it is more objective than strain elastography, conventional SWE presumes that the tissue is homogeneous, non-viscous, and isotropic, conditions the cervix does not meet, given its heterogeneous, anisotropic, and highly hydrated structure. Commercial shear wave transducers also struggle to isolate a pure shear signal from longitudinal waves, which can produce multiple reflections in a small organ like the cervix. Torsional wave elastography (TWE) is an emerging alternative that addresses both issues directly. These shear waves travel through soft tissue in a curled pattern instead of a straight line, which helps them avoid the reflection problems that affect conventional shear waves in a small organ like the cervix. CerviSense turns this physics into a practical bedside tool. It is
Understanding the mechanical role of the cervix is imperative for developing in vivo diagnostic techniques to identify women at risk of preterm birth.” We are excited to share groundbreaking insights that delve into the world of maternal healthcare with our white paper on “Torsional Waves Elastography: Potentiality to Predict the Risk of Preterm Birth.” This study explores the mechanical dynamics of the human cervix throughout pregnancy and introduces an innovative solution to predict and mitigate the risk of preterm birth. Introduction During pregnancy, the human cervix serves as a crucial mechanical barrier that undergoes substantial stresses from the developing baby. Understanding the mechanical role of the cervix is imperative for developing in vivo diagnostic techniques to identify women at risk of preterm birth. The World Health Organization (WHO) projected that around 15 million infants were born preterm (before 37 weeks of gestation) in 2017, a rate exceeding 1 in 10 newborns. (1) Problem Highlights: Addressing the Global Preterm Birth Challenge 15 million babies born preterm annually, with 45% due to True Threatened Preterm Labor. 45 million pregnant women hospitalized yearly after a Threatened Preterm Labor event. Only 15% of Threatened Preterm Labor cases result in spontaneous delivery post-event. 38 million pregnant women unnecessarily hospitalized annually due to false positive TPTL test. The economic burden of false Threatened Preterm Labor events is approximately $1.2 billion for the US & EU. What is Torsional Waves Elastography (TWE)? Torsional waves are a type of pure shear elastic waves that propagate through soft tissue radially and in-depth in a curled geometry, ideally suited to explore structures such as the cervix. (2) These torsional waves offer a unique insight into cervical structures. Recent interest surrounds cervical elastography measurements, an imaging technique estimating local axial tissue strains. Changes in collagen, elastin, and macromolecular components during pregnancy impact cervical stiffness, leading to the process of cervical maturation. The exact mechanism controlling this process remains a mystery. Fine Birth: Revolutionizing Preterm Birth Diagnostics In response to the challenges posed by preterm birth, We have introduced Fine Birth, a novel patented diagnostic tool. Fine Birth utilizes an intravaginal probe to transmit torsional waves to the cervix, measuring tissue consistency. An Artificial Intelligence algorithm interprets these measurements, providing real-time assessments of true or false preterm labor events. The information is presented as a score and associated risk level, offering a precise and cost-effective alternative to current methods. Advantages of Fine Birth Accurate differentiation between true and false preterm labor. Low false-negative and false-positive rates. Cost-effective, with practical real-time results. Innitius is a Spanish startup, that focuses on providing actionable diagnostics for women’s health. We develop medical devices combining novel technology (Torsional Waves) with Artificial Intelligence for diagnosing pathologies associated with changes in a woman’s cervical tissue consistency. (1) “Preterm Birth.” World Health Organization, World Health Organization, www.who.int/news-room/fact-sheets/detail/preterm-birth. (2) Rus, Guillermo & Riveiro, Miguel & Molina, Francisca. (2018). Effect of Contact Conditions of Torsional Wave Elastographic Probe on Human Cervix. Mathematical Problems in Engineering. 2018. 1-6. 10.1155/2018/6494758. Upcoming Events As we continue our mission to positively impact women’s health globally, we are thrilled to announce our participation in two upcoming events this year: Women’s Health Innovation Summit Europe Location: Basel, Switzerland Date: April 16-17, 2024 LSI – Life Science Intelligence in Europe ’24 Location: Portugal Date: September 16-20, 2024 We are excited about the opportunity to engage with experts, share insights, and contribute to the discourse surrounding women’s health. Stay tuned for more updates, innovations, advancements, and highlights from our participation in these events as we strive to make a positive impact on women’s health worldwide.
Dear Innitius Community, We’re happy to share an important milestone in our journey to improve obstetric care. The Spanish Agency of Medicines and Medical Devices (AEMPS) has officially approved the launch of our pivotal clinical study for CerviSense TPTL, our diagnostic tool for assessing women with symptoms of threatened preterm labor (TPTL). This is a major step forward as we continue building the evidence needed to bring CerviSense to clinical practice. This marks a critical step forward in bringing a more accurate, non-invasive, and real-time solution to a clinical area where misdiagnosis remains far too common. We believe this study will help set a new standard in maternal care. Clinical Study Overview The study, titled “Evaluation of the safety and the preterm birth predictive capacity of the clinical investigation device ‘CerviSense TPTL’: an international clinical study,” will enroll 457 patients across hospitals in Spain and Germany. It will take place in two phases: Pilot Phase This phase launched in April and is currently active in four Spanish hospitals. It is a randomized, open-label study with a recruitment period of approximately six months. Pivotal Phase Set to begin after the pilot, this phase will expand to 14 hospitals in Spain and 3 hospitals in Germany by the end of 2025. It will be conducted as a single-arm, open-label study running for approximately 14 months. Both phases will be carried out as part of the standard of care in participating hospitals. Why This Matters Each year, thousands of women are hospitalized with symptoms of preterm labor, yet current diagnostic tools are often unreliable. As a result, many receive unnecessary treatments or, worse, are sent home without adequate intervention. CerviSense aims to change that. By measuring cervical consistency through torsional wave technology, the device provides an objective, real-time indicator of whether labor is truly imminent. This has the potential to: Reduce unnecessary hospital admissions and interventions Improve outcomes for mothers and babies Empower clinicians with clearer, data-driven insights About CerviSense CerviSense TPTL uses torsional wave technology to measure the mechanical consistency of cervical tissue. This approach provides clear, real-time data that can help identify women at risk of preterm birth earlier and more accurately than current methods. Participating Spanish Hospitals We’re proud to collaborate with the following hospitals for this important research: H. Universitario San Cecilio H. Universitario de Basurto H. Universitario de Cruces H. Universitario de Torrejón H. Clínic de Barcelona H. Sant Joan de Déu H. Vall d’Hebron H. Virgen Arrixaca H. Universitario La Paz H. Universitario de Málaga H. Universitario de A Coruña H. General Universitario Gregorio Marañón H. Universitario de Donostia H. Materno Infantil de Gran Canaria We are also working with German regulators to finalize participation from three leading hospitals in Germany. Looking Ahead This study will provide key clinical evidence on the safety and predictive performance of CerviSense TPTL. It brings us one step closer to offering physicians and patients a more reliable tool to support timely decision-making in threatened preterm labor.
“Together, we are making significant strides in improving preterm labor assessment and maternal healthcare….” Dear Innitius Community, We are thrilled to share some incredibly exciting news with you all! We are delighted to announce the successful completion of Clinical Trial 1, marking a significant milestone for Innitius and a giant leap forward in our mission to revolutionize maternal healthcare. Clinical Trial Completion In April, we successfully completed the enrollment of our Phase I and Phase II clinical trial titled “Development of a Diagnostic Algorithm for Threatened Preterm Labor Assessment using the FineBirth device.” Phase I, involved 94 patients, and was focused on device usability. In Phase II, which included 258 patients, we worked on developing a diagnostic algorithm for Threatened Preterm Labor (TPTL) based on the quantification of cervical tissue stiffness in combination with clinical variables. The trial was conducted in the following sites: Hospital Universitario San Cecilio, Granada (Granada) Hospital Universitario de Torrejón de Ardoz, Torrejón (Madrid) Hospital Universitario de Cruces, Barakaldo (Bizkaia) Hospital Universitario de Basurto, Bilbao (Bizkaia) Hospital Universitario Virgen de Arixaca, Murcia (Murcia) Hospital San José, Madrid (Madrid) Hospital Universitario Dexeus, Barcelona (Barcelona) Hospital Clinic, Barcelona (Barcelona) Hospital San Joan de Deu, Barcelona (Barcelona) Hospital Vall d’Hebron, Barcelona (Barcelona) Top Recruiting Sites We are proud to announce that Hospital Universitario de Cruces had the highest recruittment rate, closely followed by Hospital Universitario San Cecilio in second place and Hospital Universitario de Torrejón in third. Acknowledgements We want to recognize the exceptional work of Alberto Maroto Ferrer, PhD, our clinical research manager, whose leadership was instrumental in the success of this trial. We would also like to acknowledge all the doctors and principal investigators involved including: Dr. Francisca Molina, Dr. Mar Gil, Dr. Jorge Burgos, Dr. Amelia Valladolid, Dr. Jose Eliseo Blanco, Dr. Carlos Piñel, Dr. Pilar Prats, Dr. Teresa Cobo, Dr. Silvia Ferrero, Dr. María Goya. Additionally, we want to extend our gratitude to the following individuals for their contributions: Alberto García Salguero, Irati Palacios Ruiz, Maialen Coca Ruiz de Azua, Pablo Diez Alonso, Francesco Corbetta, Irene Gutierrez Gonzalez, Jordi Borjas Moreno, Asier De Miguel Luengo, Carmen Andraca, Eñaut Diaz Respaldiza, Christiana Castella, Miguel José Monteiro, Miguel Torres Miranda and Rubén Molina. Next Steps: Clinical Trial 2 Looking ahead, we are excited to commence Clinical Trial 2. This next phase of our research will be conducted across Spain, Germany, and The Netherlands. The title of this study is: Evaluation of the Safety and the Preterm Birth Predictive Capacity of the Clinical Investigation Device ‘Fine Birth’: An International Clinical Study Clinical Trial 2 has been split into two studies to maximize the enrolled patients’ safety and evaluate its reliability in a clinical setting, including its failure rates and technical issues. Our clinical research efforts have expanded significantly, we are exploring new opportunities for research and collaboration in other regions. Stay tuned for more updates on our expanding clinical research program. We want to express our deepest gratitude to everyone who contributed to the success of Clinical Trial 1. Your dedication, hard work, and commitment have been truly inspiring. Together, we are making significant strides in improving preterm labor assessment and maternal healthcare. Thank you for your continued support and dedication. We look forward to the advancements and discoveries that lie ahead.ady worked with it may be more receptive. If FineBirth proves to be a quick tool, it may encounter fewer obstacles, as speed could be its greatest advantage.
