Non-pregnant Cervix Research Articles

Hyposecretion of cervical MUC5B is related to preterm birth in pregnant women after cervical excisional surgery.

Excisional surgery for cervical intraepithelial neoplasia is a risk factor for preterm birth in subsequent pregnancies. However, the underlying mechanisms of this association remain unclear. We previously showed that cervical MUC5B, a mucin protein, may be a barrier to ascending pathogens during pregnancy. We thus hypothesized that hyposecretion of cervical MUC5B is associated with preterm birth after cervical excisional surgery. This prospective nested case-control study (Study 1) included pregnant women who had previously undergone cervical excisional surgery across 11 hospitals. We used proteomics to compare cervicovaginal fluid at 18-22weeks of gestation between the preterm and term birth groups. In another case-control analysis (Study 2), we compared MUC5B expression in nonpregnant uterine tissues between 15 women with a history of cervical excisional surgery and 26 women without a history of cervical surgery. The abundance of MUC5B in cervicovaginal fluid was significantly decreased in the preterm birth group (fold change=0.41, p=.035). Among the 480 quantified proteins, MUC5B had the second highest positive correlation with gestational age at delivery in the combined preterm and term groups. The cervicovaginal microbiome composition was not significantly different between the two groups. Cervical length was not correlated with gestational age at delivery (r=0.18, p=.079). Histologically, the MUC5B-positive area in the nonpregnant cervix was significantly decreased in women with a history of cervical excisional surgery (0.85-fold, p=.048). The distribution of MUC5B-positive areas in the cervical tissues of 26 women without a history of cervical excisional surgery differed across individuals. This study suggests that the primary mechanism by which cervical excisional surgery causes preterm birth is the hyposecretion of MUC5B due to loss of the cervical glands.

Speculum-free portable preterm imaging system.

Preterm birth is defined as a birth before 37 weeks of gestation and is one of the leading contributors to infant mortality rates globally. Premature birth can lead to life-long developmental impairment for the child. Unfortunately, there is a significant lack of tools to diagnose preterm birth risk, which limits patient care and the development of new therapies. To develop a speculum-free, portable preterm imaging system (PPRIM) for cervical imaging; testing of the PPRIM system to resolve polarization properties of birefringent samples; and testing of the PPRIM under an IRB on healthy, non-pregnant volunteers for visualization and polarization analysis of cervical images. The PPRIM can perform Mueller-matrix imaging to characterize the remodeling of the uterine cervix during pregnancy. The PPRIM is built with a polarized imaging probe and a flexible insertable sheath made with a compatible flexible rubber-like material to maximize comfort and ease of use. The PPRIM device is developed to meet specific design specifications as a speculum-free, portable, and comfortable imaging system with polarized imaging capabilities. This system comprises a main imaging component and a flexible silicone inserter. The inserter is designed to maximize comfort and usability for the patient. The PPRIM shows high-resolution imaging capabilities at the 20mm working distance and 25mm circular field of view. The PPRIM demonstrates the ability to resolve birefringent sample orientation and full field capture of a healthy, non-pregnant cervix. The development of the PPRIM aims to improve access to the standard of care for women's reproductive health using polarized Mueller-matrix imaging of the cervix and reduce infant and maternal mortality rates and better quality of life.

Three-dimensional anisotropic hyperelastic constitutive model describing the mechanical response of human and mouse cervix

The mechanical function of the uterine cervix is critical for a healthy pregnancy. During pregnancy, the cervix undergoes significant softening to allow for a successful delivery. Abnormal cervical remodeling is suspected to contribute to preterm birth. Material constitutive models describing known biological shifts in pregnancy are essential to predict the mechanical integrity of the cervix. In this work, the material response of human cervical tissue under spherical indentation and uniaxial tensile tests loaded along different anatomical directions is experimentally measured. A deep-learning segmentation tool is applied to capture the tissue deformation during the uniaxial tensile tests. A 3-dimensional, equilibrium anisotropic continuous fiber constitutive model is formulated, considering collagen fiber directionality, fiber bundle dispersion, and the entropic nature of wavy cross-linked collagen molecules. Additionally, the universality of the material model is demonstrated by characterizing previously published mouse cervix mechanical data. Overall, the proposed material model captures the tension–compression asymmetric material responses and the remodeling characteristics of both human and mouse cervical tissue. The pregnant (PG) human cervix (mean locking stretch ζ=2.4, mean initial stiffness ξ=12 kPa, mean bulk modulus κ=0.26 kPa, mean dispersion b=1.0) is more compliant compared with the nonpregnant (NP) cervix (mean ζ=1.3, mean ξ=32 kPa, mean κ=1.4 kPa, mean b=1.4). Creating a validated material model, which describes the role of collagen fiber directionality, dispersion, and crosslinking, enables tissue-level biomechanical simulations to determine which material and anatomical factors drive the cervix to open prematurely. Statement of significanceIn this study, we report a 3D anisotropic hyperelastic constitutive model based on Langevin statistical mechanics and successfully describe the material behavior of both human and mouse cervical tissue using this model. This model bridges the connection between the extracellular matrix (ECM) microstructure remodeling and the macro mechanical properties change of the cervix during pregnancy via microstructure-associated material parameters. This is the first model, to our knowledge, to connect the the entropic nature of wavy cross-linked collagen molecules with the mechanical behavior of the cervix. Inspired by microstructure, this model provides a foundation to understand further the relationship between abnormal cervical ECM remodeling and preterm birth. Furthermore, with a relatively simple form, the proposed model can be applied to other fibrous tissues in the future.

A randomised comparative study of sublingual and vaginal misoprostol for cervical priming before minor gynaecological procedures

This study aimed to compare the effect of misoprostol using vaginal or sublingual routes on the non-pregnant uterine cervix prior to minor gynaecological procedures. One hundred and forty women were randomised 1:1 into two groups: A and B. Group A received misoprostol 400 mcg vaginally and pyridoxine 40 mg sublingually and Group B received misoprostol 400 mcg sublingually and pyridoxine 40 mg vaginally 4 h prior to procedure. The outcomes studied were maximum size of Hegar’s dilator that could be inserted into the cervix without any resistance, ease of dilatation, need and time required for further dilatation, side effects and complications. Baseline cervical dilatation was significantly more in Group A than Group B. Need for further dilatation and time required for further dilatation were also significantly less in Group A than Group B. Thus, we conclude that vaginal misoprostol is more effective than sublingual misoprostol in cervical priming before minor gynaecological procedures. Clinical Trial Registration Number: www.ctri.nic.in; CTRI/2018/07/015080 IMPACT STATEMENT What is already known on this subject? Cervical priming has been shown to result in shorter operative time, easier mechanical dilatation, reduced incidence of complications and blood loss when used prior to surgical abortion and has been recommended as a standard practice in various national and international guidelines for safe abortion practices. Misoprostol has many advantages over other ripening agents like osmotic dilators, other prostaglandins and mifepristone. Misoprostol can be given through oral, sublingual, vaginal, buccal and rectal routes. Use of misoprostol has been found to improve cervical dilatation, reduce need of further dilatation and ease of dilatation without many complications when compared to placebo for cervical priming of non-pregnant cervix. Studies comparing vaginal and sublingual routes have shown no significant difference for cervical ripening in pregnant women. What the results of this study add? We found that vaginal misoprostol for cervical priming was more effective than sublingual misoprostol in reaching a higher baseline cervical dilatation, with reduced need and time required for further dilatation before minor gynaecological procedures, although the ease of dilatation was similar in both groups. This effect of vaginal misoprostol was more marked in premenopausal women. What the implications are of these findings for clinical practice and/or further research? The results of our study are at variance with other studies done on use of misoprostol via the vaginal or sublingual routes, and hence it is imperative that large multi-center studies be performed to bring about consensus on the topic.

Mechanical Response of Mouse Cervices Lacking Decorin and Biglycan During Pregnancy.

Cervical remodeling is critical for a healthy pregnancy. The proper regulation of extracellular matrix (ECM) turnover leads to remodeling throughout gestation, transforming the tissue from a stiff material to a compliant, extensible, viscoelastic tissue prepared for delivery. Small leucine-rich proteoglycans (SLRPs) regulate structural fiber assembly in the cervical ECM and overall tissue material properties. To quantify the SLRPs' mechanical role in the cervix, whole cervix specimens from nonpregnant and late pregnant knockout mice of SLRPs, decorin and biglycan, were subjected to cyclic load-unload, ramp-hold, and load-to-failure mechanical tests. Further, a fiber composite material model, accounting for collagen fiber bundle waviness, was developed to describe the cervix's three-dimensional large deformation equilibrium behavior. In nonpregnant tissue, SLRP knockout cervices have the same equilibrium material properties as wild-type tissue. In contrast, the load-to-failure and ramp-hold tests reveal SLRPs impact rupture and time-dependent relaxation behavior. Loss of decorin in nonpregnant (NP) cervices results in inferior rupture properties. After extensive remodeling, cervical strength is similar between all genotypes, but the SLRP-deficient tissue has a diminished ability to dissipate stress during a ramp-hold. In mice with a combined loss of decorin and biglycan, the pregnant cervix loses its extensibility, compliance, and viscoelasticity. These results suggest that decorin and biglycan are necessary for crucial extensibility and viscoelastic material properties of a healthy, remodeled pregnant cervix.

Rapid and efficient characterization of cervical collagen orientation using linearly polarized colposcopic images

Collagen provides tissue strength and structural integrity. Quantification of the orientated dispersion of collagen fibers is an important factor when studying the mechanical properties of the cervix. In this study, for the first time, a new method for rapid characterization of the collagen fiber orientations of the cervix using linearly polarized light colposcopy is presented. A total of 24 colposcopic images were captured using a cross-polarized imaging system with white LED light sources. In the preprocessing stage, the Red channel of the RGB image was chosen, which contains no information of the blood vessels because of the low-absorption of blood cells in the red region. OrientationJ, which is an ImageJ plug-in, was used to estimate the local orientation of the collagen fibers. The result shows that in the nonpregnant cervix, the middle zone (Zone 2) has circumferentially aligned collagen fibers while the inner zone (Zone 1) has randomly arranged. The collagen fiber dispersion in Zone 2 is much smaller than that in Zone 1 at all four quadrants region (anterior, posterior, left, and right quadrant). This new analysis technique could potentially combine with diagnostic tools to provide a quantitative platform of collagen fibers in the clinic.

Transcriptome and proteome dynamics of cervical remodeling in the mouse during pregnancy†.

During gestation, the female reproductive tract must maintain pregnancy while concurrently preparing for parturition. Here, we explore the transitions in gene expression and protein turnover (fractional synthesis rates [FSR]) by which the cervix implements a transition from rigid to compliant. Shifts in gene transcription to achieve immune tolerance and alter epithelial cell programs begin in early pregnancy. Subsequently, in mid-to-late pregnancy transcriptional programs emerge that promote structural reorganization of the extracellular matrix (ECM). Stable isotope labeling revealed a striking slowdown of overall FSRs across the proteome on gestation day 6 that reverses in mid-to-late pregnancy. An exception was soluble fibrillar collagens and proteins of collagen assembly, which exhibit high turnover in nonpregnant cervix compared with other tissues and FSRs that continue throughout pregnancy. This finding provides a mechanism to explain how cross-linked collagen is replaced by newly synthesized, less cross-linked collagens, which allows increased tissue compliance during parturition. The rapid transition requires a reservoir of newly synthesized, less cross-linked collagens, which is assured by the high FSR of soluble collagens in the cervix. These findings suggest a previously unrecognized form of "metabolic flexibility" for ECM in the cervix that underlies rapid transformation in compliance to allow parturition.

Biomechanical Cervical Assessment Using 2-Dimentional Transvaginal Shear Wave Elastography in Nonpregnant and Pregnant Women: A Prospective Pilot Study.

This study evaluated the technical feasibility of 2-dimensional transvaginal shear wave elastography to quantify cervical stiffness in nonpregnant and pregnant women and established normal values in each group. With institutional review board approval, we performed a prospective study with an age-matched historical control design. Sixteen premenopausal nonpregnant women without cervical pathology and 17 low-risk pregnant women (gestational age 17-33 weeks) were enrolled. Cervical shear wave speeds were measured on a SuperSonic Aixplorer machine. The mean shear wave speeds of anterior cervix were 4.96 ± 1.96 m/s in nonpregnant women and 1.92 ± 0.31 m/s in pregnant women. No significant stiffness difference was found between the anterior and posterior cervix (P = 0.15). The upper cervix was stiffer than the lower cervix in the pregnant women (P = 0.00012). Transvaginal shear wave elastography reveals that cervix at a midterm gestation is significantly softer than nonpregnant cervix (P < 0.0001) and suggests a spatial stiffness gradient along the length of the cervix, consistent with histopathology and limited elastography literature. Our results indicate the potential of transvaginal shear wave elastography to provide objective and quantitative estimates of cervical stiffness, especially during pregnancy.

The Role of Biaxial Loading on Smooth Muscle Contractility in the Nulliparous Murine Cervix.

Throughout the estrus cycle, the extracellular matrix (ECM) and cervical smooth muscle cells (cSMC) coordinate to accomplish normal physiologic function in the non-pregnant cervix. While previous uniaxial experiments provide fundamental knowledge about cervical contractility and biomechanics, the specimen preparation is disruptive to native organ geometry and does not permit simultaneous assessment of circumferential and axial properties. Thus, a need remains to investigate cervical contractility and passive biomechanics within physiologic multiaxial loading. Biaxial inflation-extension experiments overcome these limitations by preserving geometry, ECM-cell interactions, and multiaxially loading the cervix. Utilizing in vivo pressure measurements and inflation-extension testing, this study presented methodology and examined maximum biaxial contractility and biomechanics in the nulliparous murine cervix. The study showed that increased pressure resulted in decreased contractile potential in the circumferential direction, however, axial contractility remained unaffected. Additionally, total change in axial stress ([Formula: see text]) increased significantly (p < 0.05) compared to circumferential stress ([Formula: see text]) with maximum contraction. However, passive stiffness was significantly greater (p < 0.01) in the circumferential direction. Overall, axial cSMC may have a critical function in maintaining cervical homeostasis during normal function. Potentially, a loss of axial contractility in the cervix during pregnancy may result in maladaptive remodeling such as cervical insufficiency.

17: Photoacoustic imaging of the uterine cervix: a novel method to characterize tissue composition

Mid-trimester sonographic cervical length is a powerful predictor of spontaneous preterm birth (NEJM 1996) and also identifies primiparous women at risk for cesarean delivery, due to poor progress in labor (NEJM 2008). Cervical remodeling is an important component of the common pathway of parturition. Therefore, assessing changes in cervical biochemistry could provide information about cervical status beyond that provided by cervical length and elastography. Photoacoustic imaging is a non-invasive ultrasound-based technology that captures acoustic signals emitted by the components of cervical tissue in response to laser pulses, which allows for the determination of the collagen-to-water ratio (CWR). The purpose of this study was to determine whether photoacoustic profiling of CWR can distinguish structural changes between pregnant and non-pregnant cervices. This was a prospective cohort study in which cervical biopsies were obtained at the time of hysterectomy in pre- menopausal, non-pregnant women (n=10) and at scheduled cesarean delivery in pregnant women at term who were not in labor (n=10). Specimens were imaged using a probe complemented by a fiber-optic light delivery system. The photoacoustic signals acquired within the range of wavelengths that cover the peak absorption of collagen and water were used to determine the CWR. 1) A decrease in collagen content and an increase in water content were observed in cervical specimens from pregnant women, compared to those obtained from non-pregnant women (Figure, a, b); 2) the CWR was significantly lower in pregnant than non-pregnant uterine cervices (23.3% vs 63.1%, respectively; p<0.05); 3) microscopic images from non-pregnant cervices show compact collagen bundles with minimal edema (Figure, c), confirmed with Sirius Red Stain (Figure, e, f), while specimens of pregnant women demonstrated disorganized loose collagen fibers lacking discrete bundles with intervening edema (Figure, d). Photoacoustic imaging represents a novel technique to characterize tissue composition. We propose that this noninvasive imaging technique could complement sonographic evaluation of cervical length in women at risk for preterm birth, as well as prior to the induction of labor. Moreover, this imaging method could be used to assess response to therapy (progesterone, cerclage, pessary).

Shear Wave Elastography on the Uterine Cervix: Technical Development for the Transvaginal Approach.

This research aimed to identify biological and technical confounders in the nonpregnant cervix when applying shear wave elastography with an endovaginal transducer. Cervical speed measurements were obtained at the internal and external os in the anterior and posterior portions of the cervix using a transvaginal approach in 69 nongravid patients. Reliable measurements were obtained at the external os and internal os, anteriorly and posteriorly, in 63, 55, 55, and 26 patients, respectively. The mean speed obtained at the external os, anteriorly and posteriorly, was 2.52 ± 0.49 m/s and 2.87 ± 0.63 m/s, respectively, and at the internal os, anteriorly and posteriorly, 3.29 ± 0.79 m/s and 4.10 ± 1.11 m/s, respectively. The difference in speed between all regions was statistically significant (P < .05). Ultrasound-induced artifacts appear to affect the transmission of the elastographic main pulse, with cervical position contributing to suboptimal shear wave production in the posterior cervix. Reliable shear wave propagation can be achieved in the anterior cervix in most patients.

Quantitative assessment of cervical softening during pregnancy in the Rhesus macaque with shear wave elasticity imaging

Abnormal parturition, e.g. pre- or post-term birth, is associated with maternal and neonatal morbidity and increased economic burden. This could potentially be prevented by accurate detection of abnormal softening of the uterine cervix. Shear wave elasticity imaging (SWEI) techniques that quantify tissue softness, such as shear wave speed (SWS) measurement, are promising for evaluation of the cervix. Still, interpretation of results can be complicated by biological variability (i.e. spatial variations of cervix stiffness, parity), as well as by experimental factors (i.e. type of transducer, posture during scanning). Here we investigated the ability of SWEI to detect cervical softening, as well as sources of SWS variability that can affect this task, in the pregnant and nonpregnant Rhesus macaque. Specifically, we evaluated SWS differences when imaging the cervix transabdominally with a typical linear array abdominal transducer, and transrectally with a prototype intracavitary linear array transducer. Linear mixed effects (LME) models were used to model SWS as a function of menstrual cycle day (in nonpregnant animals) and gestational age (in pregnant animals). Other variables included parity, shear wave direction, and cervix side (anterior versus posterior). In the nonpregnant cervix, the LME model indicated that SWS increased by 2% (95% confidence interval 0–3%) per day, starting eight days before menstruation. During pregnancy, SWS significantly decreased at a rate of 6% (95% CI 5–7%) per week (intracavitary approach) and 3% (95% CI 2–4%) per week (transabdominal approach), and interactions between the scanning approach and other fixed effects were also significant. These results suggest that, while absolute SWS values are influenced by factors such as scanning approach and SWEI implementation, these sources of variability do not compromise the sensitivity of SWEI to cervical softening. Our results also highlight the importance of standardizing SWEI approaches to improve their accuracy for cervical assessment.

Cellular Mechanics of Primary Human Cervical Fibroblasts: Influence of Progesterone and a Pro-inflammatory Cytokine.

The leading cause of neonatal mortality, pre-term birth, is often caused by pre-mature ripening/opening of the uterine cervix. Although cervical fibroblasts play an important role in modulating the cervix's extracellular matrix (ECM) and mechanical properties, it is not known how hormones, i.e., progesterone, and pro-inflammatory insults alter fibroblast mechanics, fibroblast-ECM interactions and the resulting changes in tissue mechanics. Here we investigate how progesterone and a pro-inflammatory cytokine, IL-1β, alter the biomechanical properties of human cervical fibroblasts and the fibroblast-ECM interactions that govern tissue-scale mechanics. Primary human fibroblasts were isolated from non-pregnant cervix and treated with estrogen/progesterone, IL-1β or both. The resulting changes in ECM gene expression, matrix remodeling, traction force generation, cell-ECM adhesion and tissue contractility were monitored. Results indicate that IL-1β induces a significant reduction in traction force and ECM adhesion independent of pre-treatment with progesterone. These cell level effects altered tissue-scale mechanics where IL-1β inhibited the contraction of a collagen gel over 6days. Interestingly, progesterone treatment alone did not modulate traction forces or gel contraction but did result in a dramatic increase in cell-ECM adhesion. Therefore, the protective effect of progesterone may be due to altered adhesion dynamics as opposed to altered ECM remodeling.

Steroid Hormones Are Key Modulators of Tissue Mechanical Function via Regulation of Collagen and Elastic Fibers.

The extracellular matrix (ECM) plays an active and dynamic role that both reflects and facilitates the functional requirements of a tissue. The mature ECM of the nonpregnant cervix is drastically reorganized during pregnancy to drive changes in tissue mechanics that ensure safe birth. In this study, our research on mice deficient in the proteoglycan decorin have led to the finding that progesterone and estrogen play distinct and complementary roles to orchestrate structural reorganization of both collagen and elastic fibers in the cervix during pregnancy. Abnormalities in collagen and elastic fiber structure and tissue mechanical function evident in the cervix of nonpregnant and early pregnant decorin-null mice transiently recover for the remainder of pregnancy only to return 1 month postpartum. Consistent with the hypothesis that pregnancy levels of progesterone and estrogen may regulate ECM organization and turnover, expressions of factors required for assembly and synthesis of collagen and elastic fibers are temporally regulated, and the ultrastructure of collagen fibrils and elastic fibers is markedly altered during pregnancy in wild-type mice. Finally, utilizing ovariectomized nonpregnant decorin-null mice, we demonstrate structural resolution of collagen and elastic fibers by progesterone or estrogen, respectively, and the potential for both ECM proteins to contribute to mechanical function. These investigations advance understanding of regulatory factors that drive specialized ECM organization and contribute to an understanding of the cervical remodeling process, which may provide insight into potential complications associated with preterm birth that impact 9.6% of live births in the United States.

Macrophage gene expression associated with remodeling of the prepartum rat cervix: microarray and pathway analyses.

As the critical gatekeeper for birth, prepartum remodeling of the cervix is associated with increased resident macrophages (Mφ), proinflammatory processes, and extracellular matrix degradation. This study tested the hypothesis that expression of genes unique to Mφs characterizes the prepartum from unremodeled nonpregnant cervix. Perfused cervix from prepartum day 21 postbreeding (D21) or nonpregnant (NP) rats, with or without Mφs, had RNA extracted and whole genome microarray analysis performed. By subtractive analyses, expression of 194 and 120 genes related to Mφs in the cervix from D21 rats were increased and decreased, respectively. In both D21 and NP groups, 158 and 57 Mφ genes were also more or less up- or down-regulated, respectively. Mφ gene expression patterns were most strongly correlated within groups and in 5 major clustering patterns. In the cervix from D21 rats, functional categories and canonical pathways of increased expression by Mφ gene related to extracellular matrix, cell proliferation, differentiation, as well as cell signaling. Pathways were characteristic of inflammation and wound healing, e.g., CD163, CD206, and CCR2. Signatures of only inflammation pathways, e.g., CSF1R, EMR1, and MMP12 were common to both D21 and NP groups. Thus, a novel and complex balance of Mφ genes and clusters differentiated the degraded extracellular matrix and cellular genomic activities in the cervix before birth from the unremodeled state. Predicted Mφ activities, pathways, and networks raise the possibility that expression patterns of specific genes characterize and promote prepartum remodeling of the cervix for parturition at term and with preterm labor.

Misoprostol for cervical ripening prior to gynecological transcervical procedures

Dilatation and curettage is frequently performed in gynecological practice. Aim of this prospective randomized double-blind placebo-controlled study was to evaluate the safety and efficacy of oral misoprostol to prime non-pregnant cervix before this procedure. Women requiring dilatation and curettage were included in the study. Exclusion criteria were visible growth in cervix or vagina, pregnancy, allergy to prostaglandins, some medical disorders. Each participant was instructed to take either 400µg of misoprostol or placebo orally 12h before the procedure. Primary outcome measure was: diameter of the largest negotiable Hegar's dilator through internal os without any resistance at the beginning of the procedure. Secondary outcome measures were: percentage of women with initial cervical dilatation of ≥5mm, time required for optimum cervical dilatation, percentage of failed procedures and complications. t test, Chi-square test and Fisher's test were used to compare the variables. Misoprostol significantly increased baseline cervical diameter in the pre-menopausal group (p<0.001), but not in post-menopausal subjects (p=0.1) and reduced time required for cervical dilatation in both pre-and post-menopausal women. The number of patients achieving initial cervical dilatation ≥5 mm was significantly greater in pre-menopausal subjects receiving misoprostol, but not significant in post-menopausal ones. The drug was also found to be effective in both nulliparous and multiparous patients. Side effects were comparable between two groups. Only nausea and vomiting were more frequent in post-menopausal misoprostol group than placebo (p=0.018). Four hundred micrograms of oral misoprostol 12h prior to dilation and curettage was found to be beneficial in cervical priming in pre-menopausal subjects. It was also found to be effective irrespective of the parity of the patients.

Cervical stenosis relieved by botulinum toxin A injection

In nulliparous or postmenopausal women, it can be difficult to dilate a non-pregnant, tightly closed cervix. A false canal, with the risk of perforation, is easily made. Several measures can be taken to soften the cervix to find the endocervical canal and dilate it, including the use of estrogen, misoprostol, and oxytocin. Laminaria is also used, primarily with pregnant women. The present study reports a single case of several unsuccessful attempts at cervical dilatation and an eventual favorable outcome via botilinum toxin A (Botox; Allergan Pharmaceuticals, Johannesburg, South Africa) injection. A 29-year-old woman with primary infertility, menorrhagia, and dysmenorrhea presented to the Durbanville Medi-Clinic Hospital in Cape Town, South Africa. She had asthma, for which she used a cortisone-containing inhaler. A laparoscopy and a hysteroscopy were attempted by a gynecologist (CvdB) with 10 years of experience. However, the cervix could not be dilated and an artificial endocervical tract was made. Two subsequent attempts at dilating the cervix, 2 months and 2 years following the initial attempt, were made by the same gynecologist. In both instances, 800-μgmisoprostolwas inserted vaginally the day before the attempted cervical dilatation. Both attempts were unsuccessful. Another cervical dilatation was attempted by the same gynecologist 21 months later. This time, 16 units of botulinum toxin A were injected into the cervix at the 1, 5, 7, and 11 o'clock positions. The patient experienced no adverse effects. Three weeks later, successful dilatation of the cervix was performed followed by curettage. Histology confirmed an endometrial polyp. Botulinum toxin A has been used successfully in the treatment of idiopathic dyspareunia and vaginismus. The recommended dose is 40 units injected into the puborectalis muscle, the rectovaginal septum, and the perineal body [1,2]. In a laboratory-based study, botulinum toxin A suppressed uterine muscle contractility by 40% [3]. In the present case, the toxin caused the cervix (which consists of a combination of connective tissue and muscle fiber) to relax. Although the exact mechanism is not clear and the long-term consequences are not known, in view of the absence of adverse effects—both in the present study and in previous reports [1,2]—botulinum toxin A can be recommended as a last resort for relaxing a tightly stenotic, nonpregnant cervix. Estrogen and misoprostol, however, should remain the first and second options, respectively, for intervention.

Assessment of the in vivo biomechanical properties of the human uterine cervix in pregnancy using the aspiration test: A feasibility study

Objective To date no diagnostic tool is yet available to objectively assess the in vivo biomechanical properties of the uterine cervix during gestation. Methods We show the first clinical application of an aspiration device to assess the in vivo biomechanical properties of the cervix in pregnancy with the aim to describe the physiological biomechanical changes throughout gestation in order to eventually detect pregnant women at risk for cervical insufficiency (CI). Results Out of 15 aspiration measurements, 12 produced valid results. The stiffness values were in the range between 0.013 and 0.068 bar/mm. The results showed a good reproducibility of the aspiration test. In our previous test series on non-pregnant cervices our repetitive measurements showed a standard deviation of >20% compared to <±10% to our data on pregnant cervices. Stiffness values are decreasing with gestational age which indicates a progressive softening of cervical tissue towards the end of pregnancy. Three pregnant women had two subsequent measurements within a time interval of four weeks. Decreasing stiffness values in the range of 20% were recorded. Discussion This preliminary study on the clinical practicability of aspiration tests showed promising results in terms of reproducibility (reliability) and clinical use (feasibility). Ongoing studies will provide further insights on its usefulness in clinical practice and in the detection of substantial changes of the cervix in pregnancy indicative for threatened preterm birth or cervical insufficiency.

In Vivo Characterization of the Mechanics of Human Uterine Cervices

The uterine cervix has to provide mechanical resistance to ensure a normal development of the fetus. This is guaranteed by the composition of its extracellular matrix, which functions as a fiber-reinforced composite. At term a complex remodeling process allows the cervical canal to open for birth. This remodeling is achieved by changes in the quality and quantity of collagen fibers and ground substance and their interplay, which influences the biomechanical behavior of the cervix but also contributes to pathologic conditions such as cervical incompetence (CI). We start by reviewing the anatomy and histological composition of the human cervix, and discuss its physiologic function and pathologic condition in pregnancy including biomechanical aspects. Established diagnostic methods on the cervix (palpation, endovaginal ultrasound) used in clinics as well as methods for assessment of cervical consistency (light-induced fluorescence, electrical current, and impedance) are discussed. We show the first clinical application of an aspiration device, which allows in vivo testing of the biomechanical properties of the cervix with the aim to establish the physiological biomechanical changes throughout gestation and to detect pregnant women at risk for CI. In a pilot study on nonpregnant cervices before and after hysterectomy we found no considerable difference in the biomechanical response between in vivo and ex vivo. An outlook on further clinical applications during pregnancy is presented.

Dynamic Changes in the Cervical Epithelial Tight Junction Complex and Differentiation Occur during Cervical Ripening and Parturition

Cervical epithelia have numerous functions that include proliferation, differentiation, maintenance of fluid balance, protection from environmental hazards, and paracellular transport of solutes via tight junctions (TJs). Epithelial functions must be tightly regulated during pregnancy and parturition as the cervix undergoes extensive growth and remodeling. This study evaluated TJ proteins, as well as markers of epithelial cell differentiation in normal and cervical ripening defective mice to gain insights into how the permeability barrier is regulated during pregnancy and parturition. Although numerous TJ proteins are expressed in the nonpregnant cervix, claudins 1 and 2 are temporally regulated in pregnancy. Claudin 1 mRNA expression is increased, whereas claudin 2 expression declines. The cellular localization of claudin 1 shifts at the end of pregnancy (gestation d 18.75) to the plasma membrane in a lattice pattern, consistent with TJs in the apical cells. The timing of claudin 1-enriched TJs coincides with initiation of terminal differentiation of cervical squamous epithelia as evidenced by the increased expression of genes by differentiated epithelia late on gestation d 18. The cervical ripening defective steroid 5alpha-reductase type 1 deficient mouse, which has an elevated local progesterone concentration, also has aberrant claudin 1 and 2 expressions, fails to form claudin 1-enriched TJs, and lacks normal expression of genes involved in epithelial terminal differentiation. These data suggest that changes in permeability barrier properties during cervical ripening are, in part, negatively regulated by progesterone, and that dynamic changes in barrier properties of the cervix occur during pregnancy and parturition.