In vivo characterization of the mechanics of human uterine cervices

Can the Acetabular Labrum Be Reconstructed With a Meniscal Allograft? An In Vivo Pig Model

BACKGROUND

No single graft type has been shown to have a benefit in acetabular labral reconstruction. The native labrum and lateral meniscus share many similarities, suggesting that the meniscus may be a promising source of graft material in labral reconstruction.

QUESTIONS/PURPOSES

Using a pig model, we sought to evaluate the healing process of fresh-frozen meniscus allograft for acetabular reconstruction by assessing (1) MRI and macroscopic observations of the meniscus allograft; (2) histologic appearance and immunohistologic evaluation of the meniscus allograft, native meniscus, and labrum; (3) microscopic assessment of the native labrum and meniscus via scanning electron microscopy; and (4) biomechanical assessment of tensile properties.

METHODS

Twelve skeletally mature male miniature Bama pigs (24 hips) were randomly divided into two groups: labral defect group (control) and lateral meniscus allograft group. The selection of Bama pig specimens was based on the similarity of their acetabular labrum to that of the human acetabular labrum, characterized by the presence of fibrocartilage-like tissue lacking blood vessels. The pigs underwent bilateral hip surgery. Briefly, a 1.5-cm-long section was resected in the anterior dorsal labrum, which was left untreated or reconstructed using an allogeneic lateral meniscus. The pigs were euthanized at 12 and 24 weeks postoperatively, and then evaluated by macroscopic observations and MRI measurement to assess the extent of coverage of the labral defect. We also performed a histologic analysis and immunohistologic evaluation to assess the composition and structure of meniscus allograft, native labrum, and meniscus, as well as scanning electron microscopy assessment of the microstructure of the native labrum and meniscus and biomechanical assessment of tensile properties.

RESULTS

Imaging measurement and macroscopic observations revealed that the resected area of the labrum was fully filled in the lateral meniscus allograft group, whereas in the control group, the labral defect remained at 24 weeks. The macroscopic scores of the meniscus allograft group (8.2 ± 0.8) were higher than those of the control groups (4.8 ± 1.0) (mean difference 3.3 [95% CI 1.6 to 5.0]; p < 0.001). Moreover, in the meniscus allograft group, histologic assessment identified fibrocartilage-like cell cluster formation at the interface between the graft and acetabulum; cells and fibers arranged perpendicularly to the acetabulum and tideline structure that were similar to those of native labrum could be observed at 24 weeks. Immunohistochemical results showed that the average optical density value of Type II collagen at the graft-acetabulum interface was increased in the meniscus allograft group at 24 weeks compared with at 12 weeks (0.259 ± 0.031 versus 0.228 ± 0.023, mean difference 0.032 [95% CI 0.003 to 0.061]; p = 0.013). Furthermore, the tensile modulus of the lateral meniscus allograft was near that of the native labrum at 24 weeks (54.7 ± 9.9 MPa versus 63.2 ± 11.3 MPa, mean difference -8.4 MPa [95% CI -38.3 to 21.4]; p = 0.212).

CONCLUSION

In a pig model, lateral meniscus allografts fully filled labral defects in labral reconstruction. Regeneration of a fibrocartilage transition zone at the graft-acetabulum interface was observed at 24 weeks.

CLINICAL RELEVANCE

The use of an autograft meniscus for labral reconstruction may be a viable option when labral tears are deemed irreparable. Before its clinical implementation, it is imperative to conduct a comparative study involving tendon grafts, which are extensively used in current clinical practice.

Bioengineering and the cervix: The past, current, and future for addressing preterm birth

The uterine cervix plays two important but opposing roles during pregnancy - as a mechanical barrier that maintains the fetus for nine months and as a compliant structure that dilates to allow for the delivery of a baby. In some pregnancies, however, the cervix softens and dilates prematurely, leading to preterm birth. Bioengineers have addressed and continue to address the lack of reduction in preterm birth rates by developing novel technologies to diagnose, prevent, and understand premature cervical remodeling. This article highlights these existing and emerging technologies and concludes with open areas of research related to the cervix and preterm birth that bioengineers are currently well-positioned to address.

Anisotropic Material Characterization of Human Cervix Tissue Based on Indentation and Inverse Finite Element Analysis

The cervix is essential to a healthy pregnancy as it must bear the increasing load caused by the growing fetus. Preterm birth is suspected to be caused by the premature softening and mechanical failure of the cervix. The objective of this paper is to measure the anisotropic mechanical properties of human cervical tissue using indentation and video extensometry. The human cervix is a layered structure, where its thick stromal core contains preferentially aligned collagen fibers embedded in a soft ground substance. The fiber composite nature of the tissue provides resistance to the complex three-dimensional loading environment of pregnancy. In this work, we detail an indentation mechanical test to obtain the force and deformation response during loading which closely matches in vivo conditions. We postulate a constitutive material model to describe the equilibrium material behavior to ramp-hold indentation, and we use an inverse finite element method based on genetic algorithm (GA) optimization to determine best-fit material parameters. We report the material properties of human cervical slices taken at different anatomical locations from women of different obstetric backgrounds. In this cohort of patients, the anterior internal os (the area where the cervix meets the uterus) of the cervix is stiffer than the anterior external os (the area closest to the vagina). The anatomic anterior and posterior quadrants of cervical tissue are more anisotropic than the left and right quadrants. There is no significant difference in material properties between samples of different parities (number of pregnancies reaching viable gestation age).

Is joint hypermobility related to preterm birth?

AIM

The aim of this study was to investigate whether women giving preterm birth have joint hypermobility.

METHODS

The study included 44 women giving preterm birth (study group) and 48 women with the history of term birth (control group). After demographic data were recorded, the presence of joint hypermobility based on the Beighton diagnostic criteria and subgroup scores were noted down. Total Beighton scores were compared between the study and control groups.

RESULTS

The total Beighton scores were significantly higher in the study group (p < .001). The study group had the highest hypermobility score for elbow hyperextension and the lowest hypermobility score for thumb hyperextension.

CONCLUSIONS

It should be kept in mind that joint hypermobility detected during follow-up of pregnancy can be related to the risk of preterm birth. Informing pregnant women with joint hypermobility about the possibility of preterm birth could be helpful.

Prediction of duration of labor based on biomechanical measurements of the cervix: A preliminary study

OBJECTIVE

Induction of labor is a common procedure in obstetrics. Predictability of duration of labor could facilitate planning as well as patient's satisfaction. The primary purpose of this study was to evaluate the usefulness of a new biomechanical measurement of the cervix based on the aspiration technique for predicting the duration of labor after induction.

STUDY DESIGN

This was a prospective single centre study. Inclusion criteria were term nulliparous pregnant women with an unfavourable cervix who needed an induction of labor. Digital (Bishop score), sonographic (cervical length and cervical consistency index (CCI)) as well as aspiration measurements (closure pressure) of the cervix were performed and compared to duration of labor. The technical feasibility and the acceptability of the measurements were explored.

RESULTS

There were no technical complications of the sonographic or aspiration measurements. Measuring the Bishop score was reported as most painful examination. Both the time to active phase of labor and the time to delivery is significantly correlated with the Bishop score, but not with the cervical length, CCI or closure pressure.

CONCLUSION

The new biomechanical measurement of the cervix, based on the aspiration technique, is technically feasible and acceptable. In our small cohort no correlation was found between the closure pressure and the duration of labor.

Analysis of the collagen fibers on autopsied patients’ uterus with the Acquired Immunodeficiency Syndrome

Abstract Objectives: to compare the percentage of collagen fibers in the autopsied women’s uterine body and cervix with and without the Acquired Immunodeficiency Syndrome (Aids). Methods: 30 autopsied women’s medical files were selected from 1988 to 2013. 30 fragments of the uterine body and 30 cervix were collected and then divided into two groups, 15 with Aids and 15 without, The quantification of the collagen fibers of the uterine body and cervix was performed on slides stained with picrosirius, using the KS-300® system. Results: the percentage of collagen fibers was lower for cervix (U=336544; p=0.001) and higher for the uterine body (U=308726,5; p=0.004) in the retroviral group when compared to the group without the disease. The percentage was higher for cervix than the uterine body in the group with Aids (t=0,4793; p=0.0031). the same result was found in the group without Aids (t=2,397; p=0.0637). Conclusions: the increase in the percentage of collagen fibers in the uterine body of women with Aids’ indicates an immune response for viral infection and reveals a failure in keeping the infection restricted to the cervix. The interpretation of the histochemical and morphometric parameters can be useful in the diagnosis associated to HIV infection, contributing for clinical improvement and life expectancy.

Collagen Fiber Orientation and Dispersion in the Upper Cervix of Non-Pregnant and Pregnant Women

The structural integrity of the cervix in pregnancy is necessary for carrying a pregnancy until term, and the organization of human cervical tissue collagen likely plays an important role in the tissue's structural function. Collagen fibers in the cervical extracellular matrix exhibit preferential directionality, and this collagen network ultrastructure is hypothesized to reorient and remodel during cervical softening and dilation at time of parturition. Within the cervix, the upper half is substantially loaded during pregnancy and is where the premature funneling starts to happen. To characterize the cervical collagen ultrastructure for the upper half of the human cervix, we imaged whole axial tissue slices from non-pregnant and pregnant women undergoing hysterectomy or cesarean hysterectomy respectively using optical coherence tomography (OCT) and implemented a pixel-wise fiber orientation tracking method to measure the distribution of fiber orientation. The collagen fiber orientation maps show that there are two radial zones and the preferential fiber direction is circumferential in a dominant outer radial zone. The OCT data also reveal that there are two anatomic regions with distinct fiber orientation and dispersion properties. These regions are labeled: Region 1-the posterior and anterior quadrants in the outer radial zone and Region 2-the left and right quadrants in the outer radial zone and all quadrants in the inner radial zone. When comparing samples from nulliparous vs multiparous women, no differences in these fiber properties were noted. Pregnant tissue samples exhibit an overall higher fiber dispersion and more heterogeneous fiber properties within the sample than non-pregnant tissue. Collectively, these OCT data suggest that collagen fiber dispersion and directionality may play a role in cervical remodeling during pregnancy, where distinct remodeling properties exist according to anatomical quadrant.

The mechanical role of the cervix in pregnancy

Appropriate mechanical function of the uterine cervix is critical for maintaining a pregnancy to term so that the fetus can develop fully. At the end of pregnancy, however, the cervix must allow delivery, which requires it to markedly soften, shorten and dilate. There are multiple pathways to spontaneous preterm birth, the leading global cause of death in children less than 5 years old, but all culminate in premature cervical change, because that is the last step in the final common pathway to delivery. The mechanisms underlying premature cervical change in pregnancy are poorly understood, and therefore current clinical protocols to assess preterm birth risk are limited to surrogate markers of mechanical function, such as sonographically measured cervical length. This is what motivates us to study the cervix, for which we propose investigating clinical cervical function in parallel with a quantitative engineering evaluation of its structural function. We aspire to develop a common translational language, as well as generate a rigorous integrated clinical-engineering framework for assessing cervical mechanical function at the cellular to organ level. In this review, we embark on that challenge by describing the current landscape of clinical, biochemical, and engineering concepts associated with the mechanical function of the cervix during pregnancy. Our goal is to use this common platform to inspire novel approaches to delineate normal and abnormal cervical function in pregnancy.

Dynamic and quasi-static mechanical testing for characterization of the viscoelastic properties of human uterine tissue

Ultrasound elastography is envisioned as an optional modality to augment standard ultrasound B-mode imaging and is a promising technique to aid in detecting uterine masses which cause abnormal uterine bleeding in both pre- and post-menopausal women. In order to determine the effectiveness of strain imaging, mechanical testing to establish the elastic contrast between normal uterine tissue and stiffer masses such as leiomyomas (fibroids) and between softer pathologies such as uterine cancer and adenomyosis has to be performed. In this paper, we evaluate the stiffness of normal uterine tissue, leiomyomas, and endometrial cancers using a EnduraTEC ElectroForce (ELF) system. We quantify the viscoelastic characteristics of uterine tissue and associated pathologies globally by using two mechanical testing approaches, namely a dynamic and a quasi-static (ramp testing) approach. For dynamic testing, 21 samples obtained from 18 patients were tested. The testing frequencies were set to 1, 10, 20, and 30 Hz. We also report on stiffness variations with pre-compression from 1% to 6% for testing at 2%, 3%, and 4% strain amplitude. Our results show that human uterine tissue stiffness is both dependent on percent pre-compression and testing frequencies. For ramp testing, 20 samples obtained from 14 patients were used. A constant strain rate of 0.1% was applied and comparable results to dynamic testing were obtained. The mean modulus contrast at 2% amplitude between normal uterine tissue (the background) and leiomyomas was 2.29 and 2.17, and between the background and cancer was 0.47 and 0.39 for dynamic and ramp testing, respectively.

Overview of the methods available for biomechanical testing of the uterine cervix in vivo

OBJECTIVE

To give an overview of the methods available for biomechanical testing of the non-pregnant and pregnant uterine cervix in vivo.

METHODS

The following databases were searched. PubMed, Embase, and Cochrane Library. Additional studies were identified from reference lists. Only studies on in vivo biomechanical testing on both pregnant and non-pregnant women were included.

MAIN OUTCOME MEASURES

Estimation of distensibility, compressibility, and biochemical composition of the uterine cervix.

RESULTS

The distensibility methods evaluated a physiologic variable and might serve as a gold standard; however, they may never be clinically useful as they involve instrumentation of the cervical canal. The compression methods evaluated an unphysiological variable but despite that, they seemed to evaluate biologically relevant figures and were non-invasive. Of the methods evaluating the biomechanical properties indirectly, those based on ultrasound may be clinically useful. Other indirect methods only measured variables within the most superficial layer of the distal uterine cervix, so further studies are needed to evaluate whether these measurements reflect the entire organ. Both compression methods and indirect methods were similar or superior to the Bishop score and to cervical length measurements regarding prediction of spontaneous preterm delivery and successful induction of labor in small studies.

CONCLUSION

The methods may have the potential to detect the biomechanical changes in the uterine cervix before the cervical length has shortened. The most promising methods need large-scale clinical testing regarding induction of labor and preterm delivery before they can be used in the clinic.

Assessment of cervicovaginal vascular endothelial growth factor in predicting preterm delivery

AIM

The aim of this study is to estimate the effectiveness of cervicovaginal vascular endothelial growth factor (VEGF) in predicting preterm delivery.

METHODS

Cervicovaginal VEGF was measured in 30 women who presented symptoms or signs of threatened preterm labor and the control group of 30 healthy pregnant patients by enzyme-linked immunoassay.

RESULTS

There was no statistically significant difference in cervicovaginal VEGF values between the threatened preterm labor group and the control group (P > 0.05). Similarly, no statistically significant difference was observed in terms of cervical length and cervicovaginal VEGF values between preterm and term-delivered groups (P > 0.05). Additionally, there was no correlation between cervicovaginal VEGF values and cervical length (P > 0.05) between the threatened preterm labor and the control groups.

CONCLUSION

No correlation was found between cervicovaginal VEGF values and the preterm delivery. However, we believe that the role of VEGF in preterm delivery needs to be investigated further in well-designed studies with larger samples.

Identification of biomechanical properties in vivo in human uterine cervix

BACKGROUND AND AIMS

The course and outcome of pregnancy is closely correlated to change of biomechanical properties of the uterine cervix. The aim of this study was to build a non-linear, fiber reinforced mechanical model of the cervix for estimation of mechanical characteristics of the cervix in early- and term-pregnant women based on recordings of in vivo pressure and diameter by means of the Functional Luminal Imaging Probe (FLIP) technology.

MATERIALS AND METHODS

Five early- and six term-pregnant women were examined with a FLIP probe. The bag on the probe was inserted into the cervical canal for concomitant measurement of diameters at 16 serial locations along the canal and the bag pressure. The bag was inflated to a maximum volume of 50 ml. A three-fiber-families model including isotropic elastin-dominated matrix and anisotropic collagen was introduced to describe the mechanical behavior of the cervical canal. The unknown geometric and mechanical parameters were calculated on the basis of the mid-cervical diameters and the intraluminal pressures during the inflation.

RESULTS

The wall thickness in the unloaded state (zero pressure applied) and mechanical properties of the matrix material (c) and collagens (c1, c2) were estimated with good fits of the calculated intraluminal pressures to the FLIP recordings during the cervical canal distension. No significant difference in the wall thickness was found between the early- and term-pregnant women (10.3 ± 0.8mm vs. 11.7 ± 2.2mm, p=0.30). The cervical matrix material and the collagen in the early-pregnant women were much stiffer than that in the term-pregnant women (p<0.05).

CONCLUSIONS

The cervical mechanical properties can be obtained from recorded pressure and diameter data in vivo via the established mechanical model. Matrix material and collagens of the cervix wall were remodeled during pregnancy. The mechanical model can be applied to other tubular visceral organs where concomitant measures of pressure and diameter can be obtained for better understanding diseases and their evolution or treatment.

Cervical stiffness evaluated in vivo by endoflip in pregnant women

Objective

To determine the stiffness of the pregnant uterine cervix in vivo.

Method

Five women in early pregnancy and six women in late pregnancy were included. The EndoFlip is a 1-m-long probe with a 12-cm-long bag mounted on the tip. The tip of the probe was inserted into the cervical canal. Sensors spaced at 0.5-cm intervals along the probe were used to determine 16 serial cross-sectional areas of the bag. The diameter of the cervical canal could thereby be determined during inflation with up to 50 ml saline solution. Tissue stiffness was calculated from the geometric profiles and the pressure-strain elastic modulus (EP) at each sensor site. Three parts of the cervix were defined: the uterus-near part, the middle and the vaginal part. The EP_max was defined as the highest EP detected along the cervical canal.

Results

The EP_max was always found in the middle part of the cervix. The median EP_max was 243 kPa (IQR, 67–422 kPa) for the early pregnant women and 5 kPa (IQR, 4–15 kPa) for those at term. In the early pregnant women the stiffness differed along the cervical length (p<0.05) whereas difference along the cervix was not found for late pregnant women. A positive correlation coefficient (Spearman’s rho) was established between the EPs of the uterus-near and the middle part (0.84), between the vaginal and the middle part (0.81), and between the uterus-near and the vaginal part (0.85).

Conclusion

This new method can estimate the stiffness along the cervical canal in vivo. This method may be useful in the clinical examination of the biomechanical properties of the uterine cervix.

System-level biomechanical approach for the evaluation of term and preterm pregnancy maintenance

Preterm birth is the primary contributor to perinatal morbidity and mortality, with those born prior to 32 weeks disproportionately contributing compared to those born at 32-37 weeks. Outcomes for babies born prematurely can be devastating. Parturition is recognized as a mechanical process that involves the two processes that are required to initiate labor: rhythmic myometrial contractions and cervical remodeling with subsequent dilation. Studies of parturition tend to separate these two processes rather than evaluate them as a unified system. The mechanical property characterization of the cervix has been primarily performed on isolated cervical tissue, with an implied understanding of the contribution from the uterine corpus. Few studies have evaluated the function of the uterine corpus in the absence of myometrial contractions or in relationship to retaining the fetus. Therefore, the cervical-uterine interaction has largely been neglected in the literature. We suggest that a system-level biomechanical approach is needed to understand pregnancy maintenance. To that end, this paper has two main goals. One goal is to highlight the gaps in current knowledge that need to be addressed in order to develop any comprehensive and clinically relevant models of the system. The second goal is to illustrate the utility of finite element models in understanding pregnancy maintenance of the cervical-uterine system. The paper targets an audience that includes the reproductive biologist/clinician and the engineer/physical scientist interested in biomechanics and the system level behavior of tissues.

Beyond cervical length: emerging technologies for assessing the pregnant cervix

Spontaneous preterm birth is a heterogeneous phenotype. A multitude of pathophysiologic pathways culminate in the final common denominator of cervical softening, shortening, and dilation that leads to preterm birth. A precise description of specific microstructural changes to the cervix is imperative if we are to identify the causative upstream molecular processes and resultant biomechanical events that are associated with each unique pathway. Currently, however, we have no reliable clinical tools for quantitative and objective evaluation, which likely contributes to the reason the singleton spontaneous preterm birth rate has not changed appreciably in >100 years. Fortunately, promising techniques to evaluate tissue hydration, collagen structure, and/or tissue elasticity are emerging. These will add to the body of knowledge about the cervix and facilitate the coordination of molecular studies and ultimately lead to novel approaches to preterm birth prediction and, finally, prevention.

Prediction of preterm birth using the cervical consistency index

OBJECTIVES

To assess the diagnostic power of a new cervical consistency index (CCI) obtained using transvaginal sonography for the prediction of spontaneous preterm birth (PTB) and to establish reference ranges for this new variable.

METHODS

Included in this prospective cross-sectional study were 1115 singleton pregnancies at 5-36 weeks of gestation. Anteroposterior cervical diameter was measured before (AP) and after (AP') application of pressure on the cervix using the transvaginal probe. The index was calculated using the formula: CCI=((AP'/AP) × 100). Cervical length was also measured. The outcomes evaluated were spontaneous PTB before 32, 34 and 37 weeks. Logistic regression and analysis of receiver-operating characteristics (ROC) curves were performed to evaluate the diagnostic power of CCI and cervical length (adjusted for gestational age). Intraclass correlation coefficients (ICCs) and Bland-Altman analysis were used to evaluate intra- and interobserver variability.

RESULTS

In the 1031 women with follow-up, the rate of spontaneous PTB before 32 weeks was 0.87%, before 34 weeks was 2.13% and before 37 weeks was 7.76% (n=80). There were 31 (3.01%) iatrogenic PTBs before 37 weeks. An inverse linear correlation between gestational age and CCI was observed, with regression equation: CCI (in %)=89.8 - 1.35 × (GA in weeks); r(2)=0.66, P<0.001. Cervical length showed an inverse quadratic, though non-significant, relationship with gestational age: CL (in mm)=31.084 - 0.0278× (GA in weeks)(2) + 1.0772× (GA in weeks); r(2)=0.076, P<0.14. The intra- and interobserver ICCs for CCI were 0.99 (95% CI, 0.988-0.994) and 0.98 (95% CI, 0.973-0.987), respectively. The area under the ROC curve for CCI in the prediction of spontaneous PTB before 32 weeks was 0.947, for spontaneous PTB before 34 weeks it was 0.943 and for spontaneous PTB before 37 weeks it was 0.907. For a 5% screen-positive rate, CCI had a sensitivity of 67%, 64% and 45% for prediction of spontaneous PTB before 32, 34 and 37 weeks, respectively, with equivalent values of 11%, 9% and 11% for cervical length.

CONCLUSIONS

CCI shows a clear inverse linear relationship with GA. Assessment of CCI is reproducible and is effective in the prediction of spontaneous PTB. This new variable appears to provide better prediction of spontaneous PTB than does cervical length.

Compression-dependent viscoelastic behavior of human cervix tissue

We have characterized the viscoelastic properties of human cervical tissue through a range of precompressional loads and testing frequencies. Mechanical testing is necessary to develop robust elasticity-based techniques for the diagnosis of cervical abnormalities. The storage modulus (E') and material damping (tan 6) were measured in 13 patients, 40 to 76 years old. Our results showed that E' increased monotonically from approximately 4.7 to 6.3 kPa over the precompression range (1-6%) for a testing frequency of 1 Hz. Increases in precompressions of 4% or greater significantly increased E' obtained after dynamic compression testing when data were normalized to 1% precompression. Tan delta remained fairly constant (approximately 0.35) and was not significantly affected by changes in precompression. E' and tan delta increased significantly with frequency. E 'monotonically increased from 4.7 to 7.9 kPa for the 1-3% compression range (lowest precompression for 2% amplitude) and from 6.3 to 10.3 kPa for the 6-8% range (highest precompression for 2% amplitude) when increasing frequency from 1 to 30 Hz. Tan delta increased montonically from 0.35 to 0.45 for 2% amplitude compressions from 1 to 30 Hz regardless of initial precompression. Our results show that precompression and testing frequency must be taken into account in order to obtain consistent measurements in mechanical diagnostic tests developed for cervical abnormalities.

Cervical ripening and insufficiency: from biochemical and molecular studies to in vivo clinical examination

To understand cervical ripening and especially the pathophysiology of cervical insufficiency, it is important to know the cervical composition: the cervix is dominated by fibrous connective tissue, consisting predominantly of Type I collagen (70%). Despite many studies of the cervix, we still rely upon relatively crude methods for clinical evaluation of the cervix. If the amount of cervical collagen plays a role in cervical insufficiency and in success of or length of induction of labor, then measurements of cervical collagen may provide an objective means of establishing the diagnosis or prognosis. We have established and reported a non-invasive means, called Collascope, to measure collagen cross-linking using light-induced fluorescence (LIF), and which is specifically designed to assess cervical ripening, and functions by measuring the natural fluorescence of non-soluble collagen in the cervix. Studies conducted in animals and humans in a variety of settings indicate that cervical function can be successfully monitored using the Collascope during pregnancy: LIF correlates negatively with gestational age and positively with time-to-delivery interval, and is predictive of delivery within 24h. Additionally LIF is significantly lower in women with cervical insufficiency. We suggest that the Collascope might be useful to better define management in cases of spontaneous preterm or induced term cervical ripening. From our studies and others, it is clear that in forecasting (pre-)term cervical ripening, the capability of the technologies and bioassays that have been generally accepted into clinical practice are limited. Any devices shown to be superior to the clinically accepted tests currently used should be quite useful for clinicians. The Collascope offers an objective measurement of both the function and state of the cervix, by directly measuring collagen cross-linking using LIF.