Pregnant Populations which Benefit from Vaginal Progesterone for Preventing Preterm Birth at <34 Weeks and Neonatal Morbidities: A Systematic Review and Meta-analysis

This study aimed to assess vaginal progesterone's effect on different populations and performed comparation between women with varied risk factors. Embase, PubMed, Cochrane library (CENTRAL) were searched without restriction to language up to February 25, 2021. Randomized controlled trials (RCTs) assessing vaginal progesterone administered to women at risk of preterm birth at <37 weeks. Two reviewers independently extracted data, and pooled relative risk (RR) with 95% confidence intervals (CIs) was calculated as well. Women with short cervix have a significantly lower risk of preterm birth at <34 weeks (pooled RR = 0.65; 95% CI: 0.55-0.77; I 2 = 0; p < 0.001; nine studies) and some neonatal morbidities; interaction tests showed that effect of vaginal progesterone differs significantly between women with short cervix and those with other risk factors (history of preterm birth, exclusive twin gestation, and vaginal bleeding). Evidences of this study showed that singleton gestations, as well as women with short cervix, benefit from vaginal progesterone in preventing preterm birth at <34 weeks and some neonatal morbidities. Women with short cervix are populations who benefit the most among other risk populations. KEY POINTS: · Vaginal progesterone reduces preterm birth and neonatal morbidities.. · Vaginal progesterone effects on some specific populations.. · Women with short cervix benefit the most..

Intra-Sonographer Correlation Between Transabdominal and Transvaginal Cervical Length Measurements and Associated Patient Demographics

OBJECTIVES

To assess transvaginal (TV) and transabdominal (TA) cervical length (CL) measurements' variability and patient factors associated with TA CL accuracy. We hypothesized that patient factors would affect the accuracy of TA CL.

METHODS

This was a prospective cohort study. During anatomy ultrasound, TA and TV CL measurements were obtained, distance from placental edge to internal cervical os assessed, and demographic questionnaires completed. Patients between 18 to 22 weeks and 6 days were included and those <18 year old or with a twin gestation were excluded. TA CL >0.5 cm different from TV length was considered inaccurate.

RESULTS

A total of 530 patients were included. Exactly 18.7% had a prior cesarean, 9.8% a preterm birth, and 2.2% a cervical procedure. Mean age and BMI were 31.1 years and 27.8 kg/m2 . Median number of living children was one. Median TA and TV CL were 3.42 and 3.53 cm. Exactly 36% (95% CI: 32-40%) of TA CL measurements were inaccurate. CL of 3.4 cm corresponded to a mean difference of zero between TA and TV CL. TA ultrasound had a sensitivity of 25% and a specificity of 98.5% to detect TV CL <2.5 cm. On multivariable analyses, Hispanic ethnicity was associated with inaccurate TA measurement (OR 0.48, 95% CI: 0.24-0.96, P = .04).

CONCLUSIONS

On average, TA CL underestimates TV CL when TV CL >3.40 cm and overestimates TV CL when TV CL <3.40 cm. Additional co-variates did not impact accuracy. TA ultrasound has low sensitivity to predict short cervix. Relying solely on TA CL to identify those who need intervention may miss diagnoses. It may be reasonable to develop protocols in which TV CL is used for TA CL <3.4 cm.

Evaluation of the distance from the anterior cervicovaginal junction to the anterior peritoneal reflection for anterior colpotomy during vaginal hysterectomy in Korean women

This study aimed to know the distance of the cervicovaginal junction (CVJ) to the anterior peritoneal reflection (APR) as measured in surgical specimens, and assess the distance between the CVJ and APR to ensure safe anterior colpotomy for vaginal hysterectomy among Korean women.Patients who underwent vaginal hysterectomy were included in the analysis. According to the presence of pelvic organ prolapse or menopausal status, the distance from the CVJ to the APR was assessed preoperatively through transvaginal ultrasonography (TV-US), as well as intraoperatively using surgical specimens. The intraclass correlation coefficient was used to determine the reliability between 2 measurements.In total, 171 patients were included. The median distance from the CVJ to the APR measured on TV-US was 19.8 (3.3-41.3) mm. Meanwhile, the median distance from the CVJ to the APR measured using the surgical specimen was 26.0 (12.0-55.0) mm. The intraclass correlation coefficient for the absolute agreement between 2 measurements was 0.353 (95% confidence interval: 0.002-0.570; P < .001), which is indicative of poor reliability. The median distance from the CVJ to the APR measured using the surgical specimen did not differ significantly between the 2 groups according to pelvic organ prolapse (26.0 [12.0-55.0] vs 27.5 [17.0-55.0] mm, P = .076] and menopausal status (27.0 [15.0-55.0] vs 26.0 [12.0-55.0] mm, P = .237).TV-US does not an accurately measure the dissection plane length from the CVJ to the APR during anterior colpotomy. During vaginal hysterectomy, the median distance from the CVJ to the APR measured using the surgical specimen was 26 (12.0-55.0) mm, which can help decrease surgical complications.

Shaping birth: variation in the birth canal and the importance of inclusive obstetric care

Regional variation in pelvic morphology and childbirth has long occurred alongside traditional labour support and an understanding of possible normal courses of childbirth for each population. The process of migration and globalization has broken down these links, while a European model of 'normal' labour has become widespread. The description of 'normal' childbirth provided within obstetrics and midwifery textbooks, in fact, is modelled on a specific pelvic morphology that is common in European women. There is mounting evidence, however, that this model is not representative of women's diversity, especially for women of non-white ethnicities. The human birth canal is very variable in shape, both within and among human populations, and differences in pelvic shapes have been associated with differences in the mechanism of labour. Normalizing a white-centred model of female anatomy and of childbirth can disadvantage women of non-European ancestry. Because they are less likely to fit within this model, pelvic shape and labour pattern in non-white women are more likely to be considered 'abnormal', potentially leading to increased rates of labour intervention. To ensure that maternal care is inclusive and as safe as possible for all women, obstetric and midwifery training need to incorporate women's diversity. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'.

Evaluation of the Arabin cervical pessary for prevention of preterm birth in women with a twin pregnancy and short cervix (STOPPIT-2): An open-label randomised trial and updated meta-analysis

BACKGROUND

Preterm-labour-associated preterm birth is a common cause of perinatal mortality and morbidity in twin pregnancy. We aimed to test the hypothesis that the Arabin pessary would reduce preterm-labour-associated preterm birth by 40% or greater in women with a twin pregnancy and a short cervix.

METHODS AND FINDINGS

We conducted an open-label randomised controlled trial in 57 hospital antenatal clinics in the UK and Europe. From 1 April 2015 to 14 February 2019, 2,228 women with a twin pregnancy underwent cervical length screening between 18 weeks 0 days and 20 weeks 6 days of gestation. In total, 503 women with cervical length ≤ 35 mm were randomly assigned to pessary in addition to standard care (n = 250, mean age 32.4 years, mean cervical length 29 mm, with pessary inserted in 230 women [92.0%]) or standard care alone (n = 253, mean age 32.7 years, mean cervical length 30 mm). The pessary was inserted before 21 completed weeks of gestation and removed at between 35 and 36 weeks or before birth if earlier. The primary obstetric outcome, spontaneous onset of labour and birth before 34 weeks 0 days of gestation, was present in 46/250 (18.4%) in the pessary group compared to 52/253 (20.6%) following standard care alone (adjusted odds ratio [aOR] 0.87 [95% CI 0.55-1.38], p = 0.54). The primary neonatal outcome-a composite of any of stillbirth, neonatal death, periventricular leukomalacia, early respiratory morbidity, intraventricular haemorrhage, necrotising enterocolitis, or proven sepsis, from birth to 28 days after the expected date of delivery-was present in 67/500 infants (13.4%) in the pessary group compared to 76/506 (15.0%) following standard care alone (aOR 0.86 [95% CI 0.54-1.36], p = 0.50). The positive and negative likelihood ratios of a short cervix (≤35 mm) to predict preterm birth before 34 weeks were 2.14 and 0.83, respectively. A meta-analysis of data from existing publications (4 studies, 313 women) and from STOPPIT-2 indicated that a cervical pessary does not reduce preterm birth before 34 weeks in women with a short cervix (risk ratio 0.74 [95% CI 0.50-1.11], p = 0.15). No women died in either arm of the study; 4.4% of babies in the Arabin pessary group and 5.5% of babies in the standard treatment group died in utero or in the neonatal period (p = 0.53). Study limitations include lack of power to exclude a smaller than 40% reduction in preterm labour associated preterm birth, and to be conclusive about subgroup analyses.

CONCLUSIONS

These results led us to reject our hypothesis that the Arabin pessary would reduce the risk of the primary outcome by 40%. Smaller treatment effects cannot be ruled out.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN 02235181. ClinicalTrials.gov NCT02235181.

Evaluation of cervical length and optimal timing for pregnancy after cervical conization in patients with cervical intraepithelial neoplasia: A retrospective study

To evaluate the change of cervical length and the best timing for pregnancy after cervical conization in patients with cervical intraepithelial neoplasia (CIN).This was a retrospective study including patients under 40 years with fertility desire treated by cervical conization for CIN. To assess the cervical length, the patients were divided into 2 groups according to different surgery procedure: loop electrosurgical excision procedure (LEEP) and cold knife conisation (CKC). Patients with cervical length < 2.5 cm in CKC group were divided into 2 groups according to whether receiving cervical cerclage. Trans-vaginal ultrasound examination was used to measure cervical length by fixed professional sonographers.In LEEP group, the cervical length preoperative was significantly longer than 3 months postoperatively (3.03 ± 0.45 cm vs 2.84 ± 0.44 cm, P = .000). In CKC group, the cervical length preoperative was significantly longer than 3 and 6 months postoperatively (2.90 ± 0.41 cm vs 2.43 ± 0.43 cm and 2.68 ± 0.41 cm, respectively, P = .000). Cervical length was significantly longer at 12 and 9 months after cerclage compared to that without cerclage. Eighteen patients got pregnant in LEEP group, among which one was pregnant at 5 months postoperatively and had premature delivery. There was 1 inevitable abortion and 1 preterm birth among 39 pregnant patients from CKC group.Patients who have fertility desire with CIN were recommended for pregnancy at 6 and 9 months after LEEP and CKC, respectively. Cerclage effectively prolonged cervical length in patents with that less than 2.5 cm to prevent cervical incompetence.

Pro-inflammatory mediators in vaginal fluid and short cervical length in pregnancy

AIM

We hypothesized that elevated vaginal levels of matrix metalloproteinase-8 (MMP-8), interleukin-8 (IL-8) and the 70kDa heat shock protein (hsp70), compounds involved in inflammatory responses, correlated with a short cervix in pregnant women.

METHODS

This prospective cohort study used a convenience sample of 64 women in their early third trimester with a singleton pregnancy. A short cervical length was present in 35 women (54.7 %). Vaginal fluid was tested for levels of MMP-8, IL-8 and hsp70 by enzyme-linked immunosorbent assay (ELISA). A receiver operating charasteristic (ROC) analysis was used to calculate the area under the curve (AUC) for each mediator in predicting short cervical length.

RESULTS

MMP-8 (109 vs 29.6 ng/ml, p=0.014), IL-8 (689 vs 330 pg/ml, p=0.007) and hsp70 (4.4 vs 2.9 ng/ml, p=0.036) were all elevated in vaginal samples from women with a short cervix. In addition, there was a negative association between the concentration of each compound in vaginal fluid and cervical length p≤0.026). The vaginal IL-8 concentration had the highest negative correlation with a short cervix (AUC=0.7, p=0.007).

CONCLUSION

MMP-8, hsp70 and IL-8 contribute to a pro-inflammatory cervico-vaginal milieu that weakens cervical integrity and leads to a shortening in cervical length (Tab. 4, Fig. 1, Ref. 27).

Effectiveness of cervical pessary compared to cervical cerclage with or without vaginal progesterone for the prevention of preterm birth in women with twin pregnancies and a short cervix: study protocol for a two-by-two factorial randomised clinical trial

INTRODUCTION

Women with twin pregnancies and a short cervix are at increased risk for preterm birth (PTB). Given the burden of prematurity and its attendant risks, the quest for effective interventions in twins has been an area of considerable research. Studies investigating the effectiveness of cervical cerclage, cervical pessary and vaginal progesterone in preventing PTB have yielded conflicting results. The aim of this study is to compare the effectiveness of cervical pessary and cervical cerclage with or without vaginal progesterone to prevent PTB in women with twin pregnancies and a cervical length (CL) ≤ 28 mm.

METHODS AND ANALYSIS

This multicentre, randomised clinical trial will be conducted at My Duc Hospital and My Duc Phu Nhuan Hospital, Vietnam. Asymptomatic women with twin pregnancies and a CL ≤28 mm, measured at 16-22 weeks' gestation, will be randomised in a 1:1:1:1 ratio to receive a cerclage, pessary, cerclage plus progesterone or pessary plus progesterone. Primary outcome will be PTB <34 weeks. Secondary outcomes will be maternal and neonatal complications. We preplanned a subgroup analysis according to CL from all women after randomisation and divided into four quartiles. Analysis will be conducted on an intention-to-treat basis. The rate of PTB <34 weeks' gestation in women with twin pregnancies and a cervix ≤28 mm and treated with pessary in our previous study at My Duc Hospital was 24.2%. A sample size of 340 women will be required to show or refute that cervical cerclage decreases the rate of PTB <34 weeks by 50% compared with pessary (from 24.2% to 12.1%, α level 0.05, power 80%, 5% lost to follow-up and protocol deviation). This study is not to be powered to assess interactions between interventions.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Institutional Ethics Committee of My Duc Hospital and informed patient consent was obtained before study enrolment. Results of the study will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03863613 (date of registration: 4 March 2019).

Effect of intra-amniotic fluid pressure from polyhydramnios on cervical length in patients with twin-twin transfusion syndrome undergoing fetoscopic laser surgery

OBJECTIVES

To determine the relationship between intra-amniotic pressure and cervical length (CL) in patients with twin-twin transfusion syndrome (TTTS) undergoing fetoscopic laser photocoagulation (FLP), and to identify pre- or intraoperative factors associated with increased intra-amniotic pressure in this population.

METHODS

This was a prospective cohort study of patients undergoing FLP for TTTS. Exclusion criteria were triplet or higher-order gestation and prior cervical cerclage, amnioreduction or FLP procedure. CL was assessed using preprocedure transvaginal ultrasound. Intra-amniotic pressure measurements were obtained on initial placement of the trocar into the amniotic cavity, using a direct hydrostatic pressure gauge. The relationship between intra-amniotic pressure and CL was assessed using multivariate linear regression analysis, including relevant preoperative and intraoperative variables.

RESULTS

In total, 283 pregnancies met the inclusion criteria. Quintero stage of TTTS was I in 33 pregnancies, II in 88, III in 150 and IV in 12. Mean gestational age (GA) at FLP was 20.7 ± 3 weeks. Mean intra-amniotic pressure was 23.1 ± 9 mmHg. On unadjusted linear regression analysis, there was no significant association between intra-amniotic pressure and preoperative CL (P = 0.24) or GA at delivery (P = 0.22). On multivariate analysis, the factors associated significantly with intra-amniotic pressure were: number of prior term deliveries (P = 0.03), recipient maximum vertical pocket (P < 0.0001), Quintero stage IV (P = 0.01) and type of anesthesia (sedation vs general anesthesia; P = 0.01).

CONCLUSION

In pregnancies with TTTS, intra-amniotic pressure is not associated with CL or GA at delivery. This novel finding suggests that cervical shortening in this population is not mechanically driven. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

[Preterm delivery: an overview on prediction, prevention and treatment]

Due to a low level of understanding of mechanisms involved in spontaneous preterm delivery there is a lack of reliable biomarkers. Existing biomarkers have a low positive predictive value but a high negative predictive value. Use of tests with high negative predictive value will reduce unnecessary interventions and hospitalization of women with threatening preterm delivery. When given to the right pregnant women, antenatal corticosteroid treatment are still the most important obstetrical intervention and reduces both neonatal mortality and short- and long-term morbidity.Several ongoing national Swedish multicenter studies may increase the understanding of the roles of cervical length, preeclampsia screening and magnesium sulfate dosage in the context of preterm delivery in a Nordic setting. Major development has been achieved in prediction and prevention of preterm preeclampsia at the cost of a 10% screen positive rate.

Echogenicity of puborectalis muscle, cervix and vastus lateralis muscle in pregnancy in relation to mode of delivery

OBJECTIVES

To confirm our previous observation that levator hiatal dimensions and mean echogenicity of the puborectalis muscle (MEP) are significantly different at 12 weeks' gestation in women who delivered by Cesarean section due to failure to progress compared with those who delivered vaginally. The secondary objective was to assess the association between the echogenicity of the cervix and vastus lateralis muscle and mode of delivery.

METHODS

In this prospective multicenter study, 306 nulliparous women with a singleton pregnancy underwent ultrasound assessments of the pelvic floor at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva maneuver, of the cervix and of the vastus lateralis muscle at 12 weeks' gestation. Dimensions of the levator hiatus, MEP and mean echogenicity of the cervix and vastus lateralis muscle were measured and compared according to mode of delivery.

RESULTS

Two hundred and forty-nine women were included in the analyses. We were unable to confirm our previous finding that MEP and levator hiatal transverse diameter and area at 12 weeks' gestation are associated significantly with mode of delivery. In addition, we could not demonstrate a significant association between echogenicity of the cervix or vastus lateralis muscle and mode of delivery. Overall, MEP was a mean of 20 points lower in women in the new database as compared with the previous study, despite the use of the same ultrasound equipment.

CONCLUSION

In a second, independent multicenter dataset, we were unable to confirm our previous finding that levator hiatal dimensions and MEP on pelvic floor muscle contraction are associated significantly with mode of delivery. We also found no association between echogenicity of the cervix or vastus lateralis and mode of delivery. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Quantitative Ultrasound Biomarkers Based on Backscattered Acoustic Power: Potential for Quantifying Remodeling of the Human Cervix during Pregnancy

As pregnancy progresses, the cervix remodels from a rigid structure to one pliable enough to allow delivery of a fetus, a process that involves progressive disorganization of cervical microstructure. Quantitative ultrasound biomarkers that may detect this process include those derived from the backscattered echo signal, namely, acoustic attenuation and backscattered power loss. We recently reported that attenuation and backscattered power loss are affected by tissue anisotropy and heterogeneity in the ex vivo cervix. In this study, we compared attenuation and backscattered power difference in a group of women in early pregnancy (first trimester) with those in a group in late pregnancy (third trimester). We observed a significant decrease in the backscattered power difference in late as compared with early pregnancy, suggesting decreased microstructural organization in late pregnancy, a finding that is consistent with animal models of cervical remodeling. In contrast, we found no difference in attenuation between the time points. These results suggest that the backscattered power difference, but perhaps not attenuation, may be a useful clinical biomarker of cervical remodeling.

Correlation between lower uterine wall thickness measured by transabdominal ultrasonography and cervical length measured by transvaginal ultrasonography in Thai pregnant women

BACKGROUND

Preterm labor is one of major obstetric challenges and can be predicted by cervical length at mid-trimester. In some settings, transvaginal ultrasound is not available and the screening and prevention of preterm labor will be suboptimal. We hope to find a correlation between other marker i.e. lower uterine wall thickness measured by transabdominal ultrasonography and cervical length measured by transvaginal ultrasonography in Thai pregnant women during 16-32 weeks of gestation.

METHODS

This study was a cross-sectional study. 166 singleton pregnant women were invited to participate in the study between June 2015 and December 2015. Transabdominal ultrasonography was performed to measure the lower uterine wall thickness and transvaginal ultrasonography was performed to measure the cervical length. The Spearman's rank correlation was used to evaluate the correlation between the two parameters. The inter-observer variation was assessed by using Bland-Altman plot. The outcomes of all pregnancies were followed and only those who delivered at term were included for the calculation of normal value of lower uterine wall thickness.

RESULTS

There was a highly positive correlation between lower uterine wall thickness and cervical length (rs = 0.767, n = 166, p < 0.001). For those who had short cervical length (defined as less than 30 mm) at GA 16-24 weeks (n = 10), the mean corresponding lower uterine wall thickness was 4.4 mm (SD 0.50). The inter-observer variation of the measurement of lower uterine wall thickness and cervical length were small. The lower uterine wall thickness tended to be slightly thinner when the gestation advanced. (mean 5.4 mm at 16-20 weeks and 5.1 mm at 28-32 weeks).

CONCLUSION

There was a highly positive correlation between lower uterine wall thickness measured by transabdominal ultrasonography and cervical length measured by transvaginal ultrasonography in Thai pregnant women.

Current options of prediction of preterm labour

OBJECTIVE

A summary of current possibilities to adequately determine spontaneous preterm labour.

DESIGN

Review.

SETTING

Department of Obstetrics and Gynecology, 1st Faculty of Medicine and General Teaching Hospital, Charles University in Prague.

METHODS

Research of literature and current studies.

CONCLUSION

Based on the combination of personal medical history, clinical signs, biomarkers and transvaginal ultrasonographic measurement of cervical length, it is possible to predict preterm labour. To avoid a major prediction miscalculation, it is necessary to understand and correctly evaluate certain clinical findings. This approach decreases redundant medical intervention and therefore leads to amelioration of perinatal outcome.

The effect of consecutive pregnancies on the ovine pelvic soft tissues: Link between biomechanical and histological components

BACKGROUND

Pelvic organ prolapse, various types of incontinence (urinary incontinence, defecatory dysfunction), chronic cystourethritis, and sexual dysfunctions remain between the most common disorders in urogynecology. Currently, it is believed that the nature and number of births plays a major role in their development. Moreover, after these events, pelvic floor tissues may not recover to their original statuses. The close anatomical relationship among the vaginal wall, bladder and rectum often contribute to the emergence of anatomical-functional failure of adjacent organs and systems.

BASIC PROCEDURES

The aim of this study was to investigate the effect of consecutive pregnancies on pelvic floor soft tissues, conducting biomechanical and histological analysis. Fifteen Swifter ewes: virgins, parous and pregnant were used. Samples, for uniaxial tension tests and histological analysis, were cut out from fresh tissue. A description of the mechanical properties of native tissue was obtained from the stress-strain curve. Histological samples were stained with Miller's Elastica staining and analyzed using ImageJ software. Collagen, elastin, and smooth muscle contents (%) were analyzed along the full wall thickness of the selected organs. The links between mechanical properties of the soft tissues and histological parameters were analyzed.

MAIN FINDINGS

Mechanically, vaginal wall tissue and cervix of pregnant sheep were more compliant. In contrast, bladder and rectum became stiffer and had the highest total collagen content. Parous sheep rectum and bladder were stiffer, compared to virgin sheep.

PRINCIPAL CONCLUSIONS

Tensile strength appears to be linked to total collagen content. Elastin and smooth muscle show a direct influence on tissue compliance.

Resolution of a Low-Lying Placenta and Placenta Previa Diagnosed at the Midtrimester Anatomy Scan

OBJECTIVES

To identify the incidence and resolution rates of a low-lying placenta or placenta previa and to assess the optimal time to perform follow-up ultrasonography (US) to assess for resolution.

METHODS

We conducted a retrospective cohort study of women with a diagnosis of a low-lying placenta or placenta previa at routine anatomic screening. Follow-up US examinations were reviewed to estimate the proportion of women who had resolution. A Kaplan-Meier survival curve was generated to estimate the median time to resolution. The distance of the placental edge from the internal cervical os was used to categorize the placenta as previa or low-lying (0.1-10 or ≥ 10-20 mm). A time-to-event analysis was used to estimate predictive factors and the time to resolution by distance from the os.

RESULTS

A total of 1663 (8.7%) women had a diagnosis of a low-lying placenta or placenta previa. The cumulative resolution for women who completed 1 or more additional US examinations was 91.9% (95% confidence interval, 90.2%-93.3%). The median time to resolution was 10 (interquartile range [IQR], 7-13) weeks. The distance from the internal cervical os was known for 658 (51.0%) women. The probability of resolution was inversely proportional to the distance from the internal os: 99.5% (≥10-20 mm), 95.4% (0.1-10 mm), and 72.3% (placenta previa; P < .001). The median times to resolution were 9 (IQR, 7-12) weeks for 10 to 20 mm, 10 (IQR, 7-13) weeks for 0.1 to 10 mm, and 12 (IQR, 9-15) weeks for placenta previa (P = .0003, log rank test).

CONCLUSIONS

A low-lying placenta or placenta previa diagnosed at the midtrimester anatomy survey resolves in most patients. Resolution is near universal in patients with an initial distance from the internal os of 10 mm or greater.

Visualisation of the insertion of a membrane for the treatment of preterm rupture of fetal membranes using a synthetic model of a pregnant uterus

Preterm premature rupture of fetal membranes is a leading cause of preterm delivery. Preterm labour can compromise fetal survival, and even if a pregnancy affected by preterm premature rupture of fetal membrane continues, major complications associated with leakage of amniotic fluid and risk of infection can affect the normal development and survival of the baby. There are limited management options for preterm premature rupture of fetal membrane other than delivery of the baby if ascending infection (chorioamnionitis) is suspected. We have previously reported the development and characterisation of an implantable membrane with the aim of using it to occlude the internal os of the cervix, in order to prevent amniotic fluid loss, allow fluid reaccumulation and reduce the risk of chorioamnionitis. For this, an electrospun biocompatible and distensible bilayer membrane was designed with mechanical properties similar to the human amniotic membrane. In this study, we consider the effects of sterilization on the membrane, how to insert the membrane and visualise it using routine clinical methods. To do this, we used e-beam sterilisation and examined the ability of the membrane to adhere to ex vivo human cervical tissues. We also studied its insertion into a custom-synthesised model of a 20-week pregnant uterus and imaged the membrane using ultrasound. Sterilisation produced minor effects on physical and mechanical properties, but these did not affect the capacity of the membrane to be sutured or to provide a fluid barrier. We demonstrated that fibrin glue can successfully adhere the bilayer membrane to cervical tissues. Finally, we demonstrated that the membrane can be inserted through the cervix as well as visualized in place using ultrasound imaging and an endoscope. In summary, we suggest this membrane is a candidate for further development in an appropriate animal model, supported by appropriate imaging, to precede possible future human studies if judged to demonstrate satisfactory safety and efficacy profiles.

Prior Uterine Evacuation and the Risk of Short Cervical Length: A Retrospective Cohort Study

OBJECTIVES

To determine whether a prior uterine evacuation procedure is associated with an increased risk of short cervical length (≤20 mm) in women without prior spontaneous preterm birth.

METHODS

This work was a retrospective cohort study from January 2012 to December 2014 of singletons without prior spontaneous preterm birth with cervical length screening between 18 weeks and 23 weeks 6 days. Women with a prior miscarriage/abortion were excluded if management (medical, surgical, or expectant) was not specified. Prior uterine evacuation was defined as dilation and curettage or dilation and evacuation of a spontaneous or induced abortion. The primary outcome was the risk of short cervical length (≤20 mm) among women with and without 1 of more prior uterine evacuations at any gestational age, assessed by the odds ratio and adjusted odds ratio for confounders.

RESULTS

Of 2672 women included, 714 (27%) had at least 1 prior uterine evacuation. The overall incidence of short cervical length in the cohort was 1% (n = 27). Women with at least 1 prior uterine evacuation were more likely to be African American (64% versus 41%; P < .001), smoke (14% versus 8%; P < .001), have a higher body mass index (mean ± SD, 28.1 ± 7.1 versus 26.8 ± 7.1 kg/m² ; P < .001), and have had prior full-term delivery (60% versus 41%; P < .001). Women with at least 1 prior uterine evacuation had a significantly higher incidence of short cervical length (2% versus 0.7%; P = .003; odds ratio, 2.99 [95% confidence interval, 1.40-6.40]). After adjustment for confounders, prior uterine evacuation remained a source of increased risk of short cervical length (adjusted odds ratio, 2.63 [95% confidence interval, 1.19-5.80]).

CONCLUSIONS

Although the overall incidence of short cervical length is low (1%-2%), women with at least 1 prior uterine evacuation have at least a 2-fold increased risk of a short second-trimester cervical length compared to women without a prior uterine evacuation.

Quantitative analysis of cervical texture by ultrasound in mid-pregnancy and association with spontaneous preterm birth

OBJECTIVE

New tools are required to improve the identification of women who are at increased risk for spontaneous preterm birth (sPTB). Quantitative analysis of tissue texture on ultrasound has been used to extract robust features from the ultrasound image to detect subtle changes in its microstructure. This may be applied to the cervix. The aim of this study was to determine if there is an association between quantitative analysis of cervical texture (CTx) on mid-trimester ultrasound and sPTB < 37 + 0 weeks' gestation.

METHODS

This was a single-center nested case-control study of a prospective cohort of 677 consecutive women with singleton pregnancy assessed between 19 + 0 and 24 + 6 weeks' gestation. Women at increased risk for sPTB were included unless they received treatment to prevent sPTB. Women who delivered < 37 + 0 weeks (sPTB) were considered as cases and were matched in a 1: 10 ratio with randomly selected contemporary controls who delivered at term. For each woman, one ultrasound image of the cervix was obtained for which quality was assessed, cervical length (CL) measured offline and a region of interest in the midportion of the anterior cervical lip delineated for use in local binary patterns analysis of CTx. A learning algorithm was developed to obtain the combination of CTx features best associated with sPTB based on feature transformation and discriminant analysis regression. The ability of the learning algorithm to predict sPTB was evaluated using a leave-one-out cross-validation technique, which produced a CTx-based score for each participant. Receiver-operating characteristics (ROC) curves were produced and sensitivity, specificity, and positive and negative likelihood ratios were calculated for the optimal cut-off based on the ROC curve. The results were compared with those obtained for CL. Investigators studying the images were blinded to pregnancy outcome at all times.

RESULTS

Images from 310 women (27 cases and 283 controls) were of sufficient quality and included in the study. Median CTx-based score was significantly lower in cases compared with controls (-1.01 vs -0.07, P ≤ 0.0001). CTx-based score maintained its significant association with sPTB after adjusting for possible confounders (history of sPTB, conization or Müllerian malformation, and CL < 25 mm). CTx-based score was a better predictor of sPTB (AUC, 0.77; 95% CI, 0.66-0.87) than was CL (AUC, 0.60; 95% CI, 0.47-0.72) (P = 0.03). Median CL was similar for cases and controls (37.7 vs 38.6 mm, P = 0.26), although cases were more likely to have CL < 25 mm (18.5% vs 0.4%, P < 0.001).

CONCLUSION

Quantitative analysis of CTx enables the extraction of information relevant to sPTB from ultrasound images to generate a CTx-based score that is associated independently with sPTB. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Mid-trimester sonographic cervical consistency index to predict spontaneous preterm birth in a low-risk population

OBJECTIVES

To investigate the effectiveness of mid-trimester sonographic cervical consistency index (CCI) for the prediction of spontaneous preterm birth (sPTB) in low-risk pregnancies and to compare its performance with that of mid-trimester sonographic cervical-length (CL) measurement.

METHODS

This was a prospective cohort study of women with a singleton pregnancy examined by ultrasound at 19 + 0 to 24 + 6 weeks' gestation. All women underwent transvaginal ultrasound examination of the cervix, but CCI and CL were measured, offline, only in women without a risk factor for sPTB. Staff and participants were blinded to CL and CCI results. CCI was obtained by calculating the ratio between the anteroposterior diameter of the uterine cervix at maximum compression and at rest. The primary outcome was prediction of sPTB before 37 + 0 weeks. Receiver-operating characteristics (ROC) curves were produced and sensitivity and specificity were calculated for the optimal cut-off based on the ROC curve and for the 1^st , 5^th and 10^th centiles of CCI and CL. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to estimate intra- and interobserver agreement and reliability for measurement of CCI and CL.

RESULTS

Of the 749 women who underwent ultrasound examination of the cervix, 532 were included for analysis. The rates of sPTB before 37 + 0 and before 34 + 0 weeks were 4.1% (22/532) and 1.3% (7/532), respectively. The rates of short cervix < 25 mm and ≤ 20 mm were 0.9% (5/532) and 0.4% (2/532), respectively. The area under the ROC curve (AUC) with regard to predicting sPTB before 37 + 0 weeks was 0.84 (95% CI, 0.75-0.93) for CCI compared with 0.68 (95% CI, 0.56-0.81) for CL (P = 0.03). The optimal cut-off based on the ROC curve was 64.6% for CCI (sensitivity, 77.3%; specificity, 82.7%) and that for CL was 37.9 mm (sensitivity, 72.7%; specificity, 61.2%). The AUC with regard to predicting sPTB before 34 + 0 weeks was 0.87 (95% CI, 0.71-1.0) for CCI compared with 0.71 (95% CI, 0.47-0.94) for CL (P = 0.25). The optimal cut-off based on the ROC curve was 63.6% for CCI (sensitivity, 85.7%; specificity, 84.0%) and that for CL was 37.9 mm (sensitivity, 85.7%; specificity, 61.3%). Intraobserver ICC was > 0.90 both for CCI and CL, while interobserver ICC was 0.89 for CCI and 0.90 for CL.

CONCLUSIONS

Second-trimester CCI is a better predictor of sPTB < 37 weeks in low-risk pregnancies than is CL. External validation is needed as well as studies assessing the value of CCI as a screening tool in unselected and high-risk populations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Detection of Changes in Cervical Softness Using Shear Wave Speed in Early versus Late Pregnancy: An in Vivo Cross-Sectional Study

The aim of this study was to assess the ability of shear wave elasticity imaging (SWEI) to detect changes in cervical softness between early and late pregnancy. Using a cross-sectional study design, shear wave speed (SWS) measurements were obtained from women in the first trimester (5-14 wk of gestation) and compared with estimates from a previous study of women at term (37-41 wk). Two sets of five SWS measurements were made using commercial SWEI applications on an ultrasound system equipped with a prototype catheter transducer (128 elements, 3-mm diameter, 14-mm aperture). Average SWS estimates were 4.42 ± 0.32 m/s (n = 12) for the first trimester and 2.13 ± 0.66 m/s (n = 18) for the third trimester (p <0.0001). The area under the curve was 0.95 (95% confidence interval: 0.82-0.99) with a sensitivity and specificity of 83%. SWS estimates indicated that the third-trimester cervix is significantly softer than the first-trimester cervix. SWEI methods may be promising for assessing changes in cervical softness.

Effects of cervical cerclage on cervical length and the impact of changes in cervical length on pregnancy prognosis

OBJECTIVE

To identify any cervix-related morphological and functional marker that can be correlated with pregnancy prognosis in patients who have undergone cerclage for cervical incompetence.

DESIGN

An observational and prospective study.

SETTING

Department of Obstetrics, Paulista School of Medicine - Federal University of São Paulo (UNIFESP-EPM).

METHODS

Patients with cervical incompetence who underwent cervical cerclage using a modified version of the McDonald procedure during or before the 22nd week of pregnancy. The patients were examined by transvaginal ultrasound in the preoperative period, the immediate postoperative period, and between 20 and 24 weeks, 24 weeks + 1 day and 28 weeks, and 28 weeks + 1 day and 32 weeks. Cervical length and the presence of funneling were evaluated during all examinations. Changes in cervical length, presence or absence of funneling, percent increase or decrease in cervical length, and cervical length of less than established values (.

Microfluidic devices for the study of sperm migration

Microfluidics technology offers us an opportunity to model the biophysical and biochemical environments encountered by sperm moving through the female reproductive tract and, at the same time, to study sperm swimming dynamics at a quantitative level. In humans, coitus results in the deposition of sperm in the vagina at the entrance to the cervix. Consequently, sperm must swim or be drawn through the cervix, uterus, uterotubal junction and oviductal isthmus to reach the oocyte in the oviductal ampulla. Only a very small percentage of inseminated sperm reach the ampulla in the periovulatory period, indicating that strong selection pressures act on sperm during migration. A better understanding of how sperm interact with the female tract would inspire improvements in diagnosis of fertility problems and development of novel-assisted reproductive technologies that minimize damage to sperm and mimic natural selection pressures on sperm.

Effect of Cervical Pessary on Spontaneous Preterm Birth in Women With Singleton Pregnancies and Short Cervical Length: A Randomized Clinical Trial

IMPORTANCE

Spontaneous preterm birth is a major cause of perinatal morbidity and mortality. It is unclear if a cervical pessary can reduce the risk of spontaneous preterm delivery.

OBJECTIVE

To test whether in asymptomatic women with singleton pregnancies and no prior spontaneous preterm birth but with short cervical length on transvaginal ultrasound, use of a cervical pessary would reduce the rate of spontaneous preterm birth at less than 34 weeks of gestation.

DESIGN, SETTING, AND PARTICIPANTS

Parallel-group, nonblinded, randomized clinical trial conducted from March 1, 2016, to May 25, 2017, at a single center in Italy. Asymptomatic women with singleton gestations, no previous spontaneous preterm births, and cervical lengths of 25 mm or less at 18 weeks 0 days to 23 weeks 6 days of gestation were eligible.

INTERVENTIONS

Patients were randomized 1:1 to receive either cervical pessary (n = 150) or no pessary (n = 150). The pessary was removed between 37 weeks 0 days and 37 weeks 6 days of gestation or earlier if clinically indicated. The control group received standard care. For cervical length of 20 mm or shorter, women in both groups were prescribed vaginal progesterone, 200 mg/d, until 36 weeks 6 days of gestation. No bed rest or activity restriction was recommended.

MAIN OUTCOMES AND MEASURES

The primary end point was spontaneous preterm birth at less than 34 weeks of gestation. Secondary outcomes were adverse events.

RESULTS

Among 300 women who were randomized (mean age, 29 [SD, 6.3] years; mean gestational age, 22 [SD, 1.3] weeks), 100% completed the trial. The primary end point occurred in 11 women (7.3%) in the pessary group and 23 women (15.3%) in the control group (between-group difference, -8.0% [95% CI, -15.7% to -0.4]; relative risk, 0.48 [95% CI, 0.24-0.95]). During follow-up, the pessary group had a higher rate of increased or new vaginal discharge (86.7% vs 46.0%; between-group difference, +40.7% [95% CI, +30.1%-+50.3%]; relative risk, 1.88 [95% CI, 1.57-2.27]).

CONCLUSIONS AND RELEVANCE

Among women without prior spontaneous preterm birth who had asymptomatic singleton pregnancies and short transvaginal cervical length, use of a cervical pessary, compared with no pessary use, resulted in a lower rate of spontaneous preterm birth at less than 34 weeks of gestation. The results of this single-center, nonblinded study among selected pregnant women require confirmation in multicenter clinical trials.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02716909.

Predicting preterm birth: Cervical length and fetal fibronectin

Spontaneous preterm birth remains the leading cause of neonatal morbidity and mortality worldwide, and accounts for a significant global health burden. Several obstetric strategies to screen for spontaneous preterm delivery, such as cervical length and fetal fibronectin measurement, have emerged. However, the effectiveness of these strategies relies on their ability to accurately predict those pregnancies at increased risk for spontaneous preterm birth (SPTB). Transvaginal cervical shortening is predictive of preterm birth and when coupled with appropriate preterm birth prevention strategies, has been associated with reductions in SPTB in asymptomatic women with a singleton gestation. The use of qualitative fetal fibronectin may be useful in conjunction with cervical length assessment in women with acute preterm labor symptoms, but data supporting its clinical utility remain limited. As both cervical length and qualitative fetal fibronectin have limited capacity to predict preterm birth, further studies are needed to investigate other potential screening modalities.

The cytokine network in women with an asymptomatic short cervix and the risk of preterm delivery

PROBLEM

To characterize the amniotic fluid (AF) inflammatory-related protein (IRP) network in patients with a sonographic short cervix (SCx) and to determine its relation to early preterm delivery (ePTD).

METHOD OF STUDY

A retrospective cohort study included women with a SCx (≤25 mm; n=223) who had amniocentesis and were classified according to gestational age (GA) at diagnosis and delivery (ePTD <32 weeks of gestation).

RESULTS

(i) In women with a SCx ≤ 22 1/7 weeks, the concentration of most IRPs increased as the cervix shortened; those with ePTD had a higher rate of increase in MIP-1α, MCP-1, and IL-6 concentrations than those delivering later; and (ii) the concentration of most IRPs and the correlation between several IRP pairs were higher in the ePTD group than for those delivering later.

CONCLUSION

Women with a SCx at 16-22 1/7 weeks have a unique AF cytokine network that correlates with cervical length at diagnosis and GA at delivery. This network may aid in predicting ePTD.

Assessment of Structural Heterogeneity and Viscosity in the Cervix Using Shear Wave Elasticity Imaging: Initial Results from a Rhesus Macaque Model

Shear wave elasticity imaging has shown promise in evaluation of the pregnant cervix. Changes in shear wave group velocity have been attributed exclusively to changes in stiffness. This assumes homogeneity within the region of interest and purely elastic tissue behavior. However, the cervix is structurally/microstructurally heterogeneous and viscoelastic. We therefore developed strategies to investigate these complex tissue properties. Shear wave elasticity imaging was performed ex vivo on 14 unripened and 13 misoprostol-ripened cervix specimens from rhesus macaques. After tests of significant and uniform shear wave displacement, as well as reliability of estimates, group velocity decreased significantly from the distal (vaginal) to proximal (uterine) end of unripened, but not ripened, specimens. Viscosity was quantified by the slope of the phase velocity versus frequency. Dispersion was observed in both groups (median: 5.5 m/s/kHz, interquartile range: 1.5-12.0 m/s/kHz), also decreasing toward the proximal cervix. This work suggests that comprehensive assessment of complex tissues such as cervix requires consideration of structural heterogeneity and viscosity.

Frequency and clinical significance of short cervix in patients with preterm premature rupture of membranes

Objective

Cervical length measurement has been uggested as a useful tool for predicting intra-amniotic infection/inflammation in preterm labor, but little information is available in the setting of preterm premature rupture of membranes (pPROM). We aimed to determine whether a short cervical length is independently associated with an increased risk of intra-amniotic infection or inflammation and impending preterm delivery in women with pPROM.

Methods

This was a retrospective cohort study involving 171 consecutive singleton pregnant women with pPROM (21+0–33+6 weeks’ gestation), who underwent amniocentesis. Amniotic fluid (AF) was cultured, and assayed for interleukin (IL)-6 and IL-8. Cervical length was measured at the time of amniocentesis by transvaginal ultrasonography with an aseptic technique. Short cervical length was defined as a cervical length of ≤15 mm. Intra-amniotic infection was defined as a positive AF culture for microorganisms and intra-amniotic inflammation was defined as elevated AF concentrations of IL-6 or IL-8 (IL-6 ≥1.5 ng/mL and/or IL-8 ≥1.3 ng/mL).

Results

Fifty (29.2%) women had a sonographic cervical length of ≤15mm. On univariate analysis, short cervical length was associated with an increased risk for intra-amniotic infection and/or inflammation; no other parameters studied showed a significant association. Multivariable analyses indicated that short cervical length was significantly associated with a higher risk of impending preterm delivery (within 2 days of measurement, within 7 days of measurement, and before 34 weeks), and remained significant after adjustment for potential confounders.

Conclusion

In women with pPROM, short cervical length is associated with an increased risk for intra-amniotic infection/inflammation and associated with impending preterm delivery, independent of the presence of intra-amniotic infection/inflammation.

Predictive Accuracy of Serial Transvaginal Cervical Lengths and Quantitative Vaginal Fetal Fibronectin Levels for Spontaneous Preterm Birth Among Nulliparous Women

Importance

Spontaneous preterm birth is a leading cause of infant mortality. Prediction, largely based on prior pregnancy outcomes, is not possible in women pregnant for the first time.

Objective

To assess the accuracy of universal screening to predict spontaneous preterm birth in nulliparous women using serial measurements of vaginal fetal fibronectin levels and cervical length.

Design, Settings, and Participants

A prospective observational cohort study of nulliparous women with singleton pregnancies, from 8 clinical sites across the United States between October 2010 and May 2014. Women and clinicians were blinded to results unless cervical shortening less than 15 mm was identified.

Exposures

Transvaginal cervical length and quantitative vaginal fetal fibronectin levels were reviewed at 2 study visits 4 or more weeks apart.

Main Outcomes and Measures

Spontaneous preterm birth at less than 37 weeks was the primary outcome. Cervical length and quantitative fetal fibronectin were considered independently and together at each visit. Measurement distributions were compared for spontaneous preterm birth vs all other births. Spontaneous preterm birth before 32 weeks was a secondary outcome.

Results

The study included 9410 women (median age, 27.0 [interquartile range, 9.0] years; 60.7% non-Hispanic white, 13.8% non-Hispanic black, 16.5% Hispanic, 4.0% Asian, and 5.1% other), of whom 474 (5.0%) had spontaneous preterm births, 335 (3.6%) had medically indicated preterm births, and 8601 (91.4%) had term births. Among women with spontaneous preterm birth, cervical length of 25 mm or less occurred in 35 of 439 (8.0%) at 16 to 22 weeks' gestation and in 94 of 403 (23.3%) at 22 to 30 weeks' gestation. Fetal fibronectin levels of 50 ng/mL or greater at 16 to 22 weeks identified 30 of 410 women (7.3%) with spontaneous preterm birth and 31 of 384 (8.1%) at 22 to 30 weeks. The area under the receiver operating characteristic curve for screening between 22 and 30 weeks for fetal fibronectin level alone was 0.59 (95% CI, 0.56-0.62), for transvaginal cervical length alone was 0.67 (95% CI, 0.64-0.70), and for the combination as continuous variables was 0.67 (95% CI, 0.64-0.70).

Conclusions and Relevance

Among nulliparous women with singleton pregnancies, quantitative vaginal fetal fibronectin and serial transvaginal ultrasound cervical length had low predictive accuracy for spontaneous preterm birth. These findings do not support routine use of these tests in such women.

Changes in Cervical Nitric Oxide Concentration Correlate With Bishop Score and Cervical Length Modifications in Prostaglandin E2-Mediated Induction of Labor

OBJECTIVE

Nitric oxide (NO) plays a fundamental role in cervical ripening and it is synthesized in the human cervix. We studied the effect of the dinoprostone on cervical NO release in pregnant women, and we investigated the relationship between cervical NO metabolites, cervical length, and Bishop score.

METHODS

Seventy-seven women underwent induction of labor at > or = 37 weeks of gestation, due to post-term pregnancy (23.8%), oligohydramnios (36.3) or preeclampsia (29.9%). Cervical fluid samples for NO metabolites (NOx), Bishop score, and cervical length were assessed immediately before (time 0 [T0]) and 6 hours after (T6) the local application of dinoprostone, a commercially available prostaglandin E2 (PGE2) analog.

RESULTS

The mean patients' age was 34 +/- 3.2 years, mean gestational age at enrollment was 284 +/- 9.2 days, and nulliparous represented 31.2% of the study population. At time 0, Bishop score was less than 4 in 74% (57/77) of the subjects, mean cervical length was 28.6 +/- 5.8 mm, mean NOx concentration was 208.6 +/- 103.8 microM/mL; 6 hours later, at T6, the mean cervical length decreased to 19.5 +/- 8.8 mm, and the mean NOx concentration increased up to 316.7 +/- 240.9 microM/mL. Data were unaffected by parity or by regular uterine contraction patterns. A statistically significant positive correlation was found between changes in cervical NOx levels and Bishop score modification (P < .01; r = .494), as well as between the modification of NO metabolites concentration and cervical shortening (P < .01; r = .307).

CONCLUSIONS

Prostaglandin (PG)-induced cervical ripening is associated with local NO release. NO plays an active role in cervical remodeling since it positively correlates with both cervical shortening and Bishop score increase. NO oxide and PG are the two pathways that, cross activating each other, trigger the cascade of events responsible of cervical ripening.

A Randomized Trial of a Cervical Pessary to Prevent Preterm Singleton Birth

BACKGROUND

Preterm birth is the leading cause of neonatal and infant death and of disability among survivors. It is unclear whether a pessary inserted around the cervix reduces the risk of preterm singleton birth.

METHODS

We conducted a multicenter, randomized, controlled trial comparing pessary placement with expectant management (control) in girls and women who were pregnant with singletons (singleton pregnancies) and who had a cervical length of 25 mm or less at 20 weeks 0 days to 24 weeks 6 days of gestation. Participants in either group who had a cervical length of 15 mm or less, at randomization or at subsequent visits, received treatment with vaginal progesterone. The primary outcome was spontaneous delivery before 34 weeks of gestation.

RESULTS

In an intention-to-treat analysis, there was no significant difference between the pessary group (465 participants) and the control group (467 participants) in the rate of spontaneous delivery before 34 weeks (12.0% and 10.8%, respectively; odds ratio in the pessary group, 1.12; 95% confidence interval, 0.75 to 1.69; P=0.57). There were no significant differences in the rates of perinatal death (3.2% in the pessary group and 2.4% in the control group, P=0.42), adverse neonatal outcome (6.7% and 5.7%, respectively; P=0.55), or neonatal special care (11.6% and 12.9%, respectively; P=0.59). The incidence of new or increased vaginal discharge was significantly higher in the pessary group than in the control group.

CONCLUSIONS

Among girls and women with singleton pregnancies who had a short cervix, a cervical pessary did not result in a lower rate of spontaneous early preterm delivery than the rate with expectant management. (Funded by the Fetal Medicine Foundation; Current Controlled Trials number, ISRCTN01096902.).

The Uterus Duplex Bicollis, Vagina Simplex of Female Chinchillas

The available literature describing the morphology of the female chinchilla's uterine cervix varies and includes phrases such as 'the cervical canal,' 'a single cervix,' and 'the cervix;' alternatively, some publications describe 2 cervices. In this report, we provide an anatomically correct and definitive description of the uterine cervical morphology of the laboratory chinchilla. We further propose revised, anatomically precise nomenclature to characterize the female chinchilla reproductive tract as a whole.

Combination of selected biochemical markers and cervical length in the prediction of impending preterm delivery in symptomatic patients

The pathophysiology of preterm delivery (PTD) is complex and multifactorial.It occurs in 8-12% of all deliveries, and the rate of PTD has increased during the past years in spite of intensive efforts towards early detection and prompt treatment. Fifty-eight pregnant women were eligible to join the study if they attended the University Clinic for Gynecology and Obstetrics, Skopje and were admitted to Department of High Risk pregnancy Unit with symptoms of preterm labor (PTL) (symptoms of uterine activity judged by the assessing physician to be indicative of PTL) at 24.0 to 36.6 weeks gestation.Test specimens for fetal fibronectin (fFN), phosphorylated insulin like growth factor binding protein 1 (phIGFBP-1), IL-6, and IL-2R and measuring the cervical length via transvaginal ultrasound were performed for each patient. The best statistical model for predicting PTL in the present study was to use a combination of the phIGFBP-1 test, a positive fFN test, cervical length less than 21.5 mm, levels of IL-6 higher than 1,305 pg/ml in the cervico-vaginal fluid (CVF), and serum levels of C-reactive protein (CRP) higher than 6.1 mg/L which was excellent at identifying the patients that were to deliver within 14 days of admittance.

[Study on morphological characteristics of uterosacral and cardinal ligament in patients with severe pelvic organ prolapse based on MRI]

OBJECTIVE

To evaluate morphological structure of uterosacral ligament (USL) and cardinal ligament (CL) in patients with severe pelvic organ prolapse (POP) by MRI technology, and to analysis and discuss its clinical significance.

METHODS

From November 2013 to February 2014 in Peking University People's Hospital, 26 elderly patients with III-IV degree of POP were selected as the POP group and 18 healthy elderly volunteers were selected as the control group during the same period. Pelvic MRI examination were performed in the two groups. The morphological characteristics of left and right side of the uterosacral-cardinal ligament on MRI and the attachment site of the starting and ending points between two group were described and compared.

RESULTS

In POP group, 25 cases of left USL starting point were located in the sacrospinous ligament/coccygeal muscle complex [58% (15/26)] or coccygeal muscle [38% (10/26)], ending point were located in the cervix and vagina [58% (15/26)] or cervix [38% (10/26)]; 24 cases of right USL starting point were located in the sacrospinous ligament/coccygeal muscle complex [31% (8/26)] or coccygeal muscle [62% (16/26)], 26 cases of right USL ending point were located in the cervix and vagina [62% (16/26)] or cervix [38% (10/26)]; the left and right CL in the POP group and the control group were both from the sacroiliac joint at the top of the greater sciatic foramen from the ipsilateral pelvic side wall; 1 case (4%, 1/26) of left CL in the POP group completely connected to the bladder, 10 cases (38%, 10/26) partly connected to the bladder; 14 cases (54%, 14/26) of right CL partly connected to the bladder, the rest ending points of left and right CL were located in cervix and (or) vagina. In the control group, 17 cases of left USL starting point were located in the sacrospinous ligament/coccygeal muscle complex (10/18) or coccygeal muscle (7/18), ending point were located in the cervix and vagina (12/18) or cervix (6/18); 18 cases of right USL starting point were located in the sacrospinous ligament/coccygeal muscle complex (10/18) or coccygeal muscle (8/18), ending point were located in the cervix and vagina (13/18) or cervix (5/18); 8 cases (8/18) of left CL partly connected to the bladder; 15 cases (15/18) of right CL partly connected to the bladder, the rest ending points of left and right CL were located in cervix and (or) vagina. There was no significant difference between the two groups on the starting and ending points (P > 0.05).

CONCLUSIONS

The observation of MRI could be consistent with the clinical anatomy on the starting and ending points, direction of travel in the uterosacral-cardinal ligament. The starting and ending points of the left and right side USL and the ending points of the left and right side CL are not completely symmetrical, the variation degree is large, some CL could be completely or partly inserted to the bladder.

STRUCTURAL BASIS OF THE VASCULAR HEMOSTATIC MECHANISM IN THE UTERINE CERVIX

The objective of the study was to investigate the angioarchitectonics and the functional morphology of the vessels of the cervix and to clarify the role of structural features of these vessels in preventing hemorrhaging in parturition during cervical dilatation. Cervixes uteri were obtained from corpses of 30 women of various ages and 5 ablated at labor. Series of histotopographical specimens of the cervixes were processed using histological and histochemical methods. Peculiar features of the angioarchitectonics, histotopography and structure of cervical vessels were encountered. Arteries penetrating the cervix are surrounded by tight muffs of anastomizing veins that are closely adjacent to the arteries. In other cases, the arteries are located within the lumen of veins--"vessels within vessels". Cervical arteries make up subendocervical convolutions. During pregnancy, smooth muscle "cushions" develop in the vessels. The cervix is pierced by a network of veins that divide the cervical tissue into separate stromal "lobules". This peculiar vascular architecture might be important structural basis of the vascular hemostatic mechanism in the neck of the uterus triggered by labor. It prevents vessel rupture, hemorrhaging and amniotic fluid and air embolism during cervical dilatation. The venous network that passes through the cervix makes it easy for the separate stromal "lobules" of the cervix to move relative to each other during cervical dilatation.

Is cervical length associated with maternal characteristics?

OBJECTIVE

Women with a mid-trimester short cervical length (CL) are at increased risk for preterm delivery. Consequently, CL measurement is a potential screening tool to identify women at risk for preterm birth. Our objective was to assess possible associations between CL and maternal characteristics.

STUDY DESIGN

A nationwide screening study was performed in which CL was measured during the standard anomaly scan among low risk women with a singleton pregnancy. Data on maternal height, pre-pregnancy weight, ethnicity, parity and gestational age at the time of the CL measurement were collected from January 2010 to December 2012. Univariable and multivariable linear regression analyses were performed to assess the relationship between CL and maternal characteristics.

RESULTS

We included 5092 women. The mean CL was 44.3mm. No association was found between CL and maternal height or gestational age of the measurement. Maternal weight was associated with CL (p=0.007, adjusted R(2) 0.03). Separate analysis for BMI did not change these results. Ethnicity, known in 2702 out of 5092 women, was associated with CL (mean CL in Caucasian women 45.0mm, Asian 43.9mm, Mediterranean 43.1mm, and African 41.8mm, p=0.003), as well as parity (mean CL multiparous 45.3mm, nulliparous 43.5mm, p<0.0001).

CONCLUSION

Shorter mid-trimester cervical length is associated with higher maternal weight, younger maternal age, nulliparity and non-Caucasian ethnicity, but not with maternal height.

The persistence of active smooth muscle in the female rat cervix through pregnancy

OBJECTIVE

A controversy exists as to whether functional smooth muscle exists in the cervix before and during pregnancy, potentially continuous with the uterus. We hypothesized that cervical smooth muscle persists through pregnancy and is functional.

STUDY DESIGN

Uteri and cervices were taken from female virgin, 11 day, and 20 day (near labor) pregnant rats. All experiments used the uterus as a positive control. Three different smooth muscle proteins (smooth muscle α-actin, SM-22α, and calponin-1) allowed immunohistochemical detection of the continuous nature of the smooth muscle from the vagina, cervix, and uterus. Tissues were also hung in isolated tissue baths for the measurement of isometric smooth muscle contraction. Uterine and cervical homogenates were also used in Western analyses to measure protein expression.

RESULTS

Immunohistochemistry revealed there to be smooth muscle as validated by an expression of all 3 markers in the cervix. This smooth muscle was continuous with that of the vagina and uterus. Smooth muscle α-actin was detected in virgin tissue (291.3 ± 32.2 arbitrary densitometry units/β-actin), day 11 (416.8 ± 19.5), and day 20 pregnant tissue (293.0 ± 34.4). The virgin, day 11, and day 20 cervices contracted 2.18 ± 0.24 g, 1.46 ± 0.08 g, and 3.88 ± 0.49 g (respectively) to depolarizing KCl. Cervices contracted at day 20 to the cholinergic muscarinic agonist carbamylcholine (maximum, 133% ± 18.2% KCl contraction, n = 4).

CONCLUSION

These findings strongly support that smooth muscle is present in the cervix through pregnancy and continuous with the uterus.

[Identification the risk of preterm labor :the role of fetal fibronectin]

Fibronectins represent a group of glycoproteins, which form "molecular glue" and are necessary in the interaction between a cell and a cell. The existence of fetal fibronectin in pregnant woman's vagina up to 22 g.w. is normal. In a normally proceeding pregnancy between 22 g.w. and 35 g.w. there is not supposed to be found fetal fibronectin in cervico-vaginal secretion. Its presence is a highly informative biological marker for the risk of premature birth.

AIM

The aim of this research was to determine the risk for premature birth through applying fetal fibronectin test as a specific marker to pregnant women with or withthout symptoms of threatened birth.

METHODS

A prospective longitudinal study has been carried out. The tests have been applied to hospitalized patients in University hospital "Majchin dom", Clinic of Pathologic pregnancy and Delivery room. Tests have been applied on 116 patients in totally). The pregnant have been separated in two groups depending on the fact of presence or absence of premature birth symptoms. The screening methods used were: the fFN test and the cervical length measurement by transvaginal according to an established protocol.

CONCLUSION

From the total of 116 patients, in 78 we have received positive tests for fetal fibronectin; in 38 - negative test. With asymptomatic patients, having higher risk of preterm birth, the percent of positive tests has been lower (14%). With asymptomatic patients with higher percent of risk factors have been: short cervix (38%), multiple pregnancy (29%), followed by patients with diagnosis of preterm birth in the past (25%) and bleeding in earlier terms. Estimating positive and negative predictive rate, we have achieved following results: The test for fetal fibronectin has excellent predictive rate - 97%, which coincides with the great deal of research until this moment in the world. Referring to the positive predictive rate--it is not sufficient--only 19%.

Successful induction of labor: prediction by preinduction cervical length, angle of progression and cervical elastography

OBJECTIVE

To examine the potential value of preinduction cervical length, cervical elastography and angle of progression (AOP) in prediction of successful vaginal delivery and induction-to-delivery interval.

METHODS

This was a prospective study in 99 women with singleton pregnancy undergoing preinduction ultrasound assessment at 35-42 weeks' gestation. Cervical length, elastographic score at the internal os and AOP were determined. Regression analysis was used to assess the relationship between cervical length and both AOP and elastographic score. Logistic regression analysis was used to determine which of the maternal characteristics (cervical length, AOP, elastographic score) were significant predictors of vaginal delivery and induction-to-delivery interval.

RESULTS

Vaginal delivery occurred in 66 (66.7%) cases and Cesarean delivery was performed in 33 (33.3%) cases. There were significant correlations between cervical length and both AOP (r = - 0.319) and elastographic score (r = 0.368). Significant independent prediction of vaginal delivery and induction-to-delivery interval was provided by nulliparity and cervical length, with no additional significant contribution from electrographic score or AOP.

CONCLUSIONS

In women undergoing induction of labor, AOP and elastographic score at the internal os are unlikely to be useful in prediction of vaginal delivery and induction-to-delivery interval.

Predicting preterm birth in women with previous preterm birth and cervical length ≥ 25 mm

OBJECTIVE

To identify risk factors predicting subsequent spontaneous preterm birth or preterm prelabor rupture of membranes (PPROM) in a cohort of women with a history of spontaneous preterm birth and a cervical length of ≥ 25 mm at 20-24 weeks' gestation.

METHODS

We identified all pregnant women who attended our preterm labor clinic between January 2010 and December 2012 because of previous spontaneous preterm birth or PPROM before 34 weeks. Women with a normal cervical length (defined as ≥ 25 mm) between 20 and 24 weeks' gestation were identified and included in the analysis. Maternal characteristics, obstetric history, shortest cervical length and gestational age at shortest cervical length of women who delivered preterm (before 37 weeks) were compared with those who delivered at or after 37 weeks in the index pregnancy. Multiple regression analysis was planned to examine the relationship between significant clinical and cervical-length variables to identify significant clinical predictors of spontaneous preterm birth among high-risk patients with a normal cervix between 20 and 24 weeks' gestation.

RESULTS

Of 134 women with a normal cervix at 20-24 weeks, 28 (20.9%) delivered spontaneously or had PPROM before 37 weeks; of these 12 (9.0%) delivered before 34 weeks. None of the selected explanatory variables was predictive of recurrent preterm birth in this cohort. No correlation between absolute cervical length and gestational age at delivery was found (R = 0.01).

CONCLUSION

In high-risk women with a cervical length of ≥ 25 mm at 20-24 weeks' gestation, demographic characteristics and absolute cervical length are not useful in predicting subsequent spontaneous preterm birth.

Rate of sonographic cervical shortening and biologic pathways of spontaneous preterm birth

OBJECTIVE

The objective of the study was to estimate the relationship between midtrimester cervical length (CL) and maternal serum markers of systemic inflammation, activation of the maternal-fetal hypothalamic-pituitary axis, and alterations in thrombosis-hemostasis.

STUDY DESIGN

This is a secondary analysis of a prospective cohort study designed to predict preterm birth in the general obstetric population. Women had serial CL ultrasounds and assessment of maternal serum corticotrophin-releasing hormone, C-reactive protein, and thrombin-antithrombin III complexes between 20 and 33 weeks' gestation and were followed up until delivery.

RESULTS

Shortening of CL was associated with the rate of rise in corticotrophin-releasing hormone (r(2) = 0.34, P = .014) and C-reactive protein (r(2) = 0.44, P = .001) for women with CL less than 25 mm but not for the cohort overall. There was no association of change in CL with change in thrombin-antithrombin III concentration.

CONCLUSION

Among women with a midtrimester sonographically short cervix, changes in serum markers suggest that a shortening CL may be associated with systemic inflammation and activation of the maternal-fetal hypothalamic-pituitary axis but not systemic thrombosis-hemostasis.

Transvaginal sonographic assessment of cervical length and wedging for predicting outcome of labor induction at term: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis to assess the predictive capacity of transvaginal sonographic assessment of the cervix for the outcome of induction of labor.

METHODS

We searched MEDLINE, EMBASE and the Cochrane Library, and manually searched reference lists of review articles and eligible primary articles. Studies in all languages were eligible if published in full. Two reviewers independently selected studies and extracted data on study characteristics, quality and test accuracy. We then calculated pooled sensitivities and specificities (with 95% CIs) and summary receiver-operating characteristics (sROC) curves. Outcome measures were test accuracy of sonographically measured cervical length and cervical wedging for Cesarean section, not achieving vaginal delivery within 24 h and not achieving active labor.

RESULTS

We included 31 studies reporting on both cervical length and outcome of delivery. The quality of the included studies was mediocre. Sensitivity of cervical length in the prediction of Cesarean delivery ranged from 0.14 to 0.92 and specificity ranged from 0.35 to 1.00. The estimated sROC curve for cervical length indicated a limited predictive capacity in the prediction of Cesarean delivery. Summary estimates of sensitivity/specificity combinations of cervical length at different cut-offs for Cesarean delivery were 0.82/0.34, 0.64/0.74 and 0.13/0.95 for 20, 30 and 40 mm, respectively. For cervical wedging in the prediction of failed induction of labor summary point estimates of sensitivity/specificity were 0.37/0.80.

CONCLUSIONS

Cervical length and cervical wedging as measured sonographically at or near term have moderate capacity to predict the outcome of delivery after induction of labor.

A simplified cervix model in response to induction balloon in pre-labour

BACKGROUND

Induction of labour is poorly understood even though it is performed in 20% of births in the United States. One method of induction, the balloon dilator applied with traction to the interior os of the cervix, engages a softening process, permitting dilation and effacement to proceed until the beginning of active labour. The purpose of this work is to develop a simple model capable of reproducing the dilation and effacement effect in the presence of a balloon.

METHODS

The cervix, anchored by the uterus and the endopelvic fascia was modelled in pre-labour. The spring-loaded, double sliding-joint, double pin-joint mechanism model was developed with a Modelica-compatible system, MapleSoft MapleSim 6.1, with a stiff Rosenbrock solver and 1E-4 absolute and relative tolerances. Total simulation time for pre-labour was seven hours and simulations ended at 4.50 cm dilation diameter and 2.25 cm effacement.

RESULTS

Three spring configurations were tested: one pin joint, one sliding joint and combined pin-joint-sliding-joint. Feedback, based on dilation speed modulated the spring values, permitting controlled dilation. Dilation diameter speed was maintained at 0.692 cm·hr-1 over the majority of the simulation time. In the sliding-joint-only mode the maximum spring constant value was 23800 N·m-1. In pin-joint-only the maximum spring constant value was 0.41 N·m·rad-1. With a sliding-joint-pin-joint pair the maximum spring constants are 2000 N·m-1 and 0.41 N·m·rad-1, respectively.

CONCLUSIONS

The model, a simplified one-quarter version of the cervix, is capable of maintaining near-constant dilation rates, similar to published clinical observations for pre-labour. Lowest spring constant values are achieved when two springs are used, but nearly identical tracking of dilation speed can be achieved with only a pin joint spring. Initial and final values for effacement and dilation also match published clinical observations. These results provide a framework for development of electro-mechanical phantoms for induction training, as well as dilator testing and development.

Costs of unnecessary admissions and treatments for "threatened preterm labor"

OBJECTIVE

Cervical length (CL) of 3 cm or greater has been shown to have a 97-99% negative predictive value for preterm delivery in women with threatened preterm labor. Consequently, hospitalization and treatment are not indicated in these patients. We analyzed how often patients with a CL of 3 cm or greater are still being admitted and treated for preterm labor and how much this contributes to the economic burden of preterm labor hospitalizations.

STUDY DESIGN

Twelve month hospitalizations for preterm labor at less than 34 weeks at a single institution were reviewed and patients with a CL of 3 cm or greater were identified. We chose to use patients' hospital charges as a surrogate for health care costs, recognizing that charges are not synonymous with the final patient bill and also do not reflect additional costs such as the cost of treatment at the referring facility, transportation, physician fees, and other such costs as lost wages, need for additional child care, etc.

RESULTS

Between July 2009 and June 2010, 139 patients were admitted and treated for preterm labor at our level III center. Fifty of these patients (36%) had a CL of 3 cm or greater. None of them delivered preterm. Total hospital charges for the management of these patients were $1,018 589 (mean, $20,372; median, $14,444).

CONCLUSION

Unnecessary admissions and treatments for threatened preterm labor are part of clinical practice and contribute to exploding health care costs. Using currently available diagnostics, these costs could be lowered significantly without jeopardizing outcome.

[Clinical treatment in shorten cervix]

Preterm birth (PrTB) remains a major cause of perinatal morbidity and mortality. This article reviews the various diagnostic methods (midtrimester Cervical Length measurement on Transvaginal ultrasonography, fFN) and interventions in the different patient groups and proposes some algorithms for management women with short cervix.

An endoscopic diffuse optical tomographic method based on the effective detection range

Endoscopic diffuse optical tomography (DOT) is a new medical imaging modality with the potential applications in functional imaging of the internal organs. To cut down the measurement time and the computation burden of image reconstruction, in this paper, we developed the image reconstruction algorithm with the partial measurement in the effective detection range (EDR) of a tubular tissue and the corresponding endoscopic imaging system with a novel endoscopic probe for flexibly selecting the detection sites. For a typical inner size and optical properties of the cervix, it is found that EDR is less than half of the inner circumference. Comparing to the traditional method, the adoption of EDR results in a reduction of more than a factor of two in the time cost for a measurement cycle and for the total iteration reconstruction. Images reconstructed from the simulation data demonstrate that the proposed method achieves equivalent image quality to that obtained from the complete data set. The images reconstructed from the EDR measurements on cervix-like solid phantoms show that both the location and size of the targets are reconstructed correctly. The proposed method will be useful to the development of endoscopic DOT technologies for cancer detection in tubular organs including cervix.