Sonographic Cervical Length Research Articles

Serial cervical length determination in twin pregnancies reveals 4 distinct patterns with prognostic significance for preterm birth

Women with a twin gestation are at increased risk for preterm birth (PTB), and sonographic cervical length (CL) is a powerful predictor for spontaneous PTB. Obstetricians frequently monitor CL in multiple gestations; yet, the optimal method to integrate and interpret the results of serial sonographic CL has not been determined. We sought to determine whether there are different patterns of cervical shortening in twin gestations, and whether such patterns are related to the risk of PTB. We conducted a retrospective study of all women with twins followed up in a single tertiary referral center during 2012 through 2014. All women underwent serial measurements of CL every 2-3 weeks starting from 14-18 weeks and until 28-32 weeks of gestation. Changes in CL were analyzed and classified into distinct patterns that were initially identified by visual inspection of all individual cases. Each pattern was then characterized by several parameters including information about when cervical shortening began, the rate of shortening, and whether a plateau was observed. Locally weighted regression mean profiles were generated to describe each pattern of CL over time. The association of these patterns with spontaneous PTB was determined. The specific characteristics of each pattern that further determined the risk of PTB were identified using multivariable logistic regression analysis. We studied 441 women who had a total of 2826 measurements of CL done. Overall, 4 main patterns of change in CL were identified: pattern I, stable cervix (n= 196); pattern II, early and rapid shortening (n= 18); pattern III, late shortening (n= 109); and pattern IV, early shortening with a plateau (n= 118). The rate of PTB at <34 weeks was lowest in cases of pattern I (11.7%), followed by pattern IV (14.4%) and pattern III (20.2%), and was highest for women with pattern II (44.4%) (P < .001). In cases with pattern III (late shortening), the most important factors affecting the risk of PTB were the shortening rate, the gestational age at the onset of cervical shortening, and the initial plateau of CL. In the case of pattern IV (early shortening with a plateau), it was only the new plateau at which cervical shortening stopped that was associated with the risk of PTB. Changes in sonographic CL over time in twin gestations can be classified into 4 patterns, each associated with a different risk of PTB.

Are Second Trimester Apparent Diffusion Coefficient Values of the Short Uterine Cervix Associated with Impending Preterm Delivery?

Purpose To prospectively determine whether the apparent diffusion coefficient (ADC) of the cervix is associated with preterm delivery in asymptomatic patients with a sonographic cervical length of 15 mm or less and positive fetal fibronectin test results between 23 and 28 weeks of gestation. Materials and Methods The institutional review board approved this prospective hypotheses-generating study. A total of 30 pregnant women (mean gestational age, 26 weeks) with a sonographic short cervix (≤15 mm) underwent pelvic 1.5-T magnetic resonance (MR) imaging. Oblique sagittal diffusion-weighted images were obtained with b values of 0, 400, and 800 sec/mm(2). ADC values at MR imaging of the subglandular and stromal cervix and the difference between both were correlated to the interval to delivery. Receiver operating characteristic curve analysis was performed to obtain sensitivity and specificity of ADC values in association with delivery within 7 days. Results Eight (27%) of 30 patients delivered within 6 or 7 days after MR imaging (impending delivery group), and 22 (73%) of 30 patients delivered between 18 and 89 days after imaging (mean, 55 days) (late delivery group). Mean subglandular ADC and mean ADC difference were higher (P < .001) in patients with impending delivery than in those with late delivery ([2406.3 ± 166.0] × 10(-6) mm(2)/sec vs [1708.9 ± 108.1] × 10(-6) mm(2)/sec and [657.3 ± 129.9] × 10(-6) mm(2)/sec vs [69.2 ± 70.2] × 10(-6) mm(2)/sec, respectively). Subglandular ADC inversely correlated with the interval between MR imaging and delivery (r = -0.75). Receiver operating characteristic curve analysis of subglandular ADC revealed 100% sensitivity (95% confidence interval: 63.1, 100) and 100% specificity (95% confidence interval: 84.6, 100) in association with impending delivery with a 1921 × 10(-6) mm(2)/sec threshold. Stromal ADC and sonographic cervical length showed no difference between groups (P = .072 and P = .511, respectively). Conclusion Cervical subglandular ADC at MR imaging is associated with impending preterm birth in patients with a short sonographic cervix. (©) RSNA, 2016.

Assessment of a cervicometer compared to transvaginal ultrasound in identifying women with a short cervical length: a multicenter study

Preterm birth remains a major cause of neonatal morbidity and mortality worldwide. Short cervical length (CL) as measured by transvaginal ultrasound (TVU) in the second trimester represents the single most predictive risk factor for spontaneous preterm birth. Previous studies have addressed, in part, the limitations of TVU availability by utilizing a cervicometer to screen patients for short cervix, identifying those patients who may not benefit from TVU CL screening. In view of the prior studies indicating that a cervicometer measurement may have a high negative predictive value (NPV) for a sonographically short cervix, we sought to identify the ideal cervicometer threshold value in a prospective, multicenter study. The primary objective was to determine the cervicometer CL measurement threshold that provides a high NPV for the identification of patients who are highly unlikely to have a TVU CL measurement ≤20 and ≤25 mm and, therefore, may forego TVU. This prospective study, executed in 5 US centers, included 401 women ≥18 years of age who provided written informed consent to undergo CL measurement in the mid trimester. All women underwent both cervicometer- and TVU-measured CLs by individuals blinded to results of the other measurement. Both measurements were performed at 17-23 weeks' gestation (visit 1) and repeated at 24-29 weeks' gestation (visit 2). All TVU measurement images were reviewed by a central reader. Test characteristics and receiver operating characteristic curves were created to determine and confirm the optimal cervicometer CL threshold, maximizing the NPV. In all, 358 subjects were evaluable at visit 1 and 267 at visit 2. At visit 1, the average TVU CL was 38.7 ± 7.6 mm and the average cervicometer CL was 30.3 ± 8.8 mm. Similar measurements were seen at visit 2. Receiver operating characteristic curves were utilized to graphically identify a cervicometer CL threshold of 30 mm that maximized sensitivity while minimizing the false-positive rate. The 30-mm cervicometer CL threshold provided a 98-100% NPV and 0.0 negative likelihood ratio for identification of women who have a low likelihood to have a sonographic short cervix (ie, transvaginal CL ≤20 mm or ≤25 mm). The 17-23 weeks' gestation 30-mm cervicometer CL threshold has 100% sensitivity, 45-46% specificity, and 1.8 and 0.0 positive and negative likelihood ratios to predict sonographic CL ≤20 and ≤25 mm. Cervicometer CL screening successfully identifies women at low risk for short transvaginal CL. Use of a 30-mm threshold by cervicometer CL measurement confers a 98-100% NPV, with high sensitivity and moderate specificity to predict a TVU short CL. Cervicometer measurement of CL may permit almost 50% of women to avoid TVU.

ACES: Accurate Cervical Evaluation With Sonography.

Transvaginal sonographic cervical length screening is an important tool for the evaluation of preterm labor. However, a structured curriculum is lacking in obstetrics and gynecology residency programs. The Accurate Cervical Evaluation with Sonography (ACES) program was developed to address this deficiency and combines an online didactic course with a standardized performance assessment of live scans. We sought to evaluate the effectiveness of the ACES program to teach residents sonographic cervical length assessment. All obstetrics and gynecology residents at our institution were invited to participate from 2012 to 2013. The program consisted of an initial supervised transvaginal cervical evaluation, an online didactic course and written examination, and 5 subsequent supervised scans. The instructor performed an independent cervical length measurement at each encounter. The primary outcome was the difference in cervical length measurement between the resident and instructor. We hypothesized that this difference would decrease over time. At each visit, a 10-item checklist was used for skill assessment. Comparisons of checklist scores over time were also performed. Seventeen of 20 residents completed at least some of the training, and 10 completed the entire program. The median difference in cervical length measurement between residents and instructors at posttests 3, 4, and 5 improved significantly compared to the pretest scan (all P ≤ .02). Similarly, the checklist scores improved over time (all P ≤ .0008). Transvaginal cervical sonography is an important tool in the evaluation of preterm labor. The ACES program provides residents a structured curriculum for cervical evaluation and supervisors a standardized means of evaluating trainees' skills.

Cervical pessary to prevent preterm birth in women with twin gestation and sonographic short cervix: a multicenter randomized controlled trial (PECEP-Twins)

Spontaneous preterm birth (SPB) is the leading cause of perinatal morbidity and mortality. In twins, the rate of preterm birth is higher than in singletons; interventions to prevent preterm birth are needed in this high-risk population. We sought to test whether a cervical pessary reduces the preterm birth rate in twin pregnancies with sonographic short cervix. A prospective, open-label, multicenter, randomized clinical trial was conducted in 5 hospitals in Spain. The ethics committees of all participating hospitals approved the protocol. The trial was registered as ClinicalTrials.gov, number NCT01242410. Eligible women were scanned in Spain. The primary outcome was SPB <34 weeks of gestation. Neonatal morbidity and mortality were also evaluated. Cervical length was measured in 2287 women; 137 pregnant women with a sonographic cervical length ≤25 mm (of 154 detected with a short cervix) were randomly assigned to receive a cervical pessary or expectant management (1:1 ratio). SPB <34 weeks of gestation was significantly less frequent in the pessary group than in the expectant management group (11/68 [16.2%] vs 26/66 [39.4%]; relative risk, 0.41; 95% confidence interval, 0.22-0.76). Pessary use was associated with a significant reduction in the rate of birthweight <2500 g (P= .01). No significant differences were observed in composite neonatal morbidity outcome (8/136 [5.9%] vs 12/130 [9.1%]; relative risk, 0.64; 95% confidence interval, 0.27-1.50) or neonatal mortality (none) between the groups. No serious adverse effects associated with the use of a cervical pessary were observed. The insertion of a cervical pessary was associated with a significant reduction in the SPB rate. We propose the use of a cervical pessary for preventing preterm birth in twin pregnancies of mothers with a short cervix.

Prediction of impending preterm delivery based on sonographic cervical length and different cytokine levels in cervicovaginal fluid in preterm labor.

The aim of this study was to determine whether cervicovaginal interleukin (IL)-1β, IL-6 and IL-8 levels, and cervical length, alone or in combination, could predict impending preterm delivery in women with preterm labor and intact membranes. Cervicovaginal swab samples for IL-1β, IL-6, and IL-8 assays were taken from 136 consecutive women with preterm labor (23-34 weeks) before the transvaginal ultrasonography examination to measure cervical length. The primary outcome measurement was spontaneous preterm delivery within 7 days of sampling. Spontaneous preterm delivery within 7 days occurred in 28.6% (39/136) of patients. Receiver-operator characteristic (ROC) curves indicated that cervical length (P < 0.001), cervicovaginal IL-6 (P < 0.001) and IL-8 (P = 0.014), but not IL-1β, could predict delivery within 7 days. According to the logistic regression analysis, high cervicovaginal IL-8 (P = 0.008) and IL-6 (P = 0.038) levels and short cervical length (P < 0.001) were significantly associated with delivery within 7 days, even after controlling for baseline variables. A combination of cervix length and cervicovaginal IL-8 increased the specificity of detecting delivery within 7 days to 92.8%, which was superior to either test alone (P < 0.001), but the sensitivity was only 56.4%. In women with preterm labor, among the parameters assessed, cervicovaginal IL-6 and IL-8 and cervical length are the most important parameters in predicting impending preterm delivery. A combination of cervix length and cervicovaginal IL-8 appeared to be the best for predicting impending preterm delivery, but the relatively low sensitivity of this test may limit its clinical usefulness.

The use of sonographic cervical length assessment for the prediction of time from induction to delivery

Objective: The objective of this study is to investigate the role of trans-vaginal cervical length measurement in the prediction of the interval to successful vaginal delivery after induction of labor with balloon catheter. Methods: In this prospective study of cervical length measurement before induction of labor, singleton pregnancies that underwent induction of labor between 37 and 42 weeks of gestation were included. The data collected included trans-vaginal sonographic cervical measurements followed by digital cervical assessment. Bishop score was used to quantify digital assessment (before induction of labor). Results: During the study period, 71 patients were included in the study. A statistically significant linear correlation was found between sonographic cervical length prior to induction of labor and the time of delivery (Pearson correlation 0.335; p values 0.005). Of the 57 vaginal deliveries, 27 patients had a cervical length of less than 28 mm. Patients with a cervical length of less than 28 mm had a significantly shorter time to delivery compared to patients with more than 28 mm length (20.4 versus 28.7, respectively; p value = 0.019). Cervical length of 28 mm remained significantly correlated even after performing several logistic regression models in order to control for confounders such as parity and age. In addition, a correlation was found between Bishop scores of above 7 to the time to delivery. Conclusions: Cervical length is correlated linearly to the time interval between induction of labor and delivery. A cervical length of less than 28 mm was found to be statistically significant in predicting a shorter time to delivery.

Vaginal progesterone to prevent preterm birth in pregnant women with a sonographic short cervix: clinical and public health implications

Vaginal progesterone administration to women with a sonographic short cervix is an efficacious and safe intervention used to prevent preterm birth and neonatal morbidity and mortality. The clinical and public health implications of this approach in the United States have been critically appraised and compared to other therapeutic interventions in obstetrics. Vaginal progesterone administration to women with a transvaginal sonographic cervical length (CL) ≤25 mm before 25 weeks of gestation is associated with a significant and substantial reduction of the risk for preterm birth from <28 to <35 weeks of gestation, respiratory distress syndrome, composite neonatal morbidity and mortality, admission to the neonatal intensive care unit, and mechanical ventilation. These beneficial effects have been achieved in women with a singleton gestation, with or without a history of spontaneous preterm birth, and did not differ significantly as a function of CL (<10 mm, 10-20 mm, or 21-25 mm). The number of patients required for treatment to prevent 1 case of preterm birth or adverse neonatal outcomes ranges from 10-19 women. The number needed to screen for the prevention of 1 case of preterm birth before 34 weeks of gestation is 125 women, and 225 for the prevention of 1 case of major neonatal morbidity or neonatal mortality. Several cost-effectiveness and decision analyses have shown that the combination of universal transvaginal CL screening and vaginal progesterone administration to women with a short cervix is a cost-effective intervention that prevents preterm birth and associated perinatal morbidity and mortality. Universal assessment of CL and treatment with vaginal progesterone for singleton gestations in the United States would result in an annual reduction of approximately 30,000 preterm births before 34 weeks of gestation and of 17,500 cases of major neonatal morbidity or neonatal mortality. In summary, there is compelling evidence to recommend universal transvaginal CL screening at 18-24 weeks of gestation in women with a singleton gestation and to offer vaginal progesterone to those with a CL ≤25 mm, regardless of the history of spontaneous preterm birth, with the goal of preventing preterm birth and neonatal morbidity and mortality.

Does educational intervention affect resident competence in sonographic cervical length measurement?

Objective: To determine if a structured teaching module improves resident competency in transvaginal sonographic cervical length measurements. Methods: This was a prospective cohort study involving obstetrics and gynecology residents at a single institution. Residents collected 10 transvaginal cervical images from patients with threatened preterm labor presenting to Labor and Delivery. After initial image acquisition, residents participated in a lecture-based teaching module involving a pre- and post-intervention assessment. Following the didactic session, they collected 10 additional images. All the images were scored independently by two Maternal–Fetal Medicine attending physicians based on the quality and accuracy of the measured cervical length. Pre-and post- intervention test results were compared, as well as pre- and post- intervention image scores. Parametric and nonparametric tests were used as appropriate with p < 0.05 considered significant. Results: Ninety-three percent of the residents (14/15) improved their scores from pre-test to post-test or maintained an already perfect score (p < 0.01). Improvement was most significant with the junior residents. Seventy-nine percent of the residents (11/14) improved their cervical image scores after the educational session. Mean score for total residents was 73.7 + 12.6 pre-intervention and 90.2 + 9.9 post-intervention (p < 0.01) out of a total of 120. Conclusions: There is an improvement in the competence of resident measured cervical lengths via transvaginal ultrasound when a structured educational module is implemented for resident education.

Predictive value of cervical length in women with twin pregnancy presenting with threatened preterm labor.

To assess the accuracy and determine the optimal threshold of sonographic cervical length (CL) for the prediction of preterm delivery (PTD) in women with twin pregnancies presenting with threatened preterm labor (PTL). This was a retrospective study of women with twin pregnancies who presented with threatened PTL and underwent sonographic measurement of CL in a tertiary center. The accuracy of CL in predicting PTD in women with twin pregnancies was compared with that in a control group of women with singleton pregnancies. Overall, 218 women with a twin pregnancy and 1077 women with a singleton pregnancy, who presented with PTL, were included in the study. The performance of CL as a predictive test for PTD was similar in twins and singletons, as reflected by the similar correlation between CL and the examination-to-delivery interval (r, 0.30 vs 0.29; P = 0.9), the similar association of CL with risk of PTD, and the similar areas under the receiver-operating characteristics curves for differing delivery outcomes (range, 0.653-0.724 vs 0.620-0.682, respectively; P = 0.3). The optimal threshold of CL for any given target sensitivity or specificity was lower in twin than in singleton pregnancies. However, in order to achieve a negative predictive value of 95%, a higher threshold (28-30 mm) should be used in twin pregnancies. Using this twin-specific CL threshold, women with twins who present with PTL are more likely to have a positive CL test, and therefore to require subsequent interventions, than are women with singleton pregnancies with PTL (55% vs 4.2%, respectively). In women with PTL, the performance of CL as a test for the prediction of PTD is similar in twin and singleton pregnancies. However, the optimal threshold of CL for the prediction of PTD appears to be higher in twin pregnancies, mainly owing to the higher baseline risk for PTD in these pregnancies.

Gestational Age at Cervical Length and Fetal Fibronectin Assessment and the Incidence of Spontaneous Preterm Birth in Twins

To estimate the risk of spontaneous preterm birth in twin pregnancies based on transvaginal sonographic cervical length, fetal fibronectin (fFN) testing, and the gestational age at which these tests were performed. Women with twin pregnancies, cervical length assessment, and fFN testing between 22 weeks and 31 weeks 6 days in a single maternal-fetal medicine practice from 2005 to 2013 were included. All testing was done on asymptomatic women on an out-patient basis. Women with monochorionic monoamniotic twins and twin-twin transfusion were excluded. Logistic regression analysis was used to estimate the risk of spontaneous preterm birth before 35, 32, and 28 weeks. Six hundred eleven patients were included and underwent a total of 2406 cervical length measurements and 2279 fFN tests over the course of the study period. The likelihood values for spontaneous preterm birth before 35, 32, and 28 weeks were 19.1%, 6.3%, and 2.3%, respectively. The risk of spontaneous preterm birth before 35 weeks increased with a decreasing cervical length (coefficient for the log of the odds ratio [OR coefficient], -0.13; P < .01; 95% confidence interval [CI], -0.22 to -0.037), a positive fFN result (OR coefficient, 1.04; P < .01; 95% CI, 0.45 to 1.64), as well as earlier gestational ages at testing (OR coefficient, -0.214; P < .01; 95% CI, -0.33 to -0.10). Similar results were seen for spontaneous preterm birth before 32 and 28 weeks. In asymptomatic patients with twin pregnancies, the cervical length, fFN, and gestational age are all significantly associated with spontaneous preterm birth.

Relationship between interpregnancy interval and cervical length in high-risk women

Objective: Our objective was to evaluate the relationship between the interpregnancy interval (IPI) and next-pregnancy mid-trimester cervical length (CL) in women at high risk for recurrent spontaneous preterm birth (SPTB).Methods: Retrospective review identified high-risk women, defined as a prior SPTB <36 weeks, who began scheduled serial transvaginal sonographic CL screening at 16–18 weeks gestation between December 2008 and November 2010. All CL assessment ended by 226/7 weeks, and weekly 17-α hydroxyprogesterone caproate, 250 mg IM, was recommended to all patients. Details of the prior and current pregnancy were collected, and regression models were used to evaluate the relationship between IPI and CL shortening.Results: One hundred and eight women with singleton gestations and a qualifying SPTB underwent CL screening. The mean (SD) birth gestational age (GA) of the last pregnancy was 25 (10) weeks, the median IPI was 613 (range 49–6038) days, and the mean (SD) delivery GA in the current pregnancy was 36 (5.3) weeks. Linear regression found no significant relationship between the IPI and the GA of the current birth (p = 0.98). There was a weak significant relationship between IPI and shortest CL (p = 0.04). However, after controlling for the GA of the prior pregnancy, this relationship was non-significant (p = 0.13).Conclusions: IPI does not predict next birth outcome or next-pregnancy mid-trimester CL in high-risk women managed with progesterone and ultrasound-indicated cerclage.

Individualized assessment of preterm birth risk using two modified prediction models

ObjectivesTo construct two prediction models for individualized assessment of preterm delivery risk within 48h and before completed 32 weeks of gestation and to test the validity of modified and previously published models. Study designData on 617 consecutive women with preterm labor transferred to a tertiary care center for threatened preterm delivery between 22 and 32 weeks of gestation were analysed. Variables predicting the risk of delivery within 48h and before completed 32 weeks of gestation were assessed and applied to previously published prediction models. Multivariate analyses identified variables that were incorporated into two modified models that were subsequently validated. ResultsTwo modified prediction models were developed and internally validated, incorporating four and six of the following variables to predict the risk of delivery within 48h and before completed 32 weeks of gestation, respectively: presence of preterm premature rupture of membranes and/or vaginal bleeding, sonographic cervical length, week of gestation, fetal fibronectin, and serum C-reactive protein. The correspondence between the actual and the predicted preterm birth rates suggests excellent calibration of the models. Internal validation analyses for the modified 48h and 32 week prediction models revealed considerably high concordance-indices of 0.8 (95%CI: [0.70–0.81]) and 0.85 (95%CI: [0.82–0.90]), respectively. ConclusionsTwo modified prediction models to assess the risk of preterm birth were constructed and validated. The models can be used for individualized prediction of preterm birth and allow more accurate risk assessment than based upon a single risk factor. An online-based risk-calculator was constructed and can be assessed through: http://cemsiis.meduniwien.ac.at/en/kb/science-research/software/clinical-software/prematurebirth/.

Vaginal progesterone and cervical cerclage for preterm labor prevention and their impact on perinatal outcome

ObjectiveThe main aim of this study was to evaluate the efficacy of progesterone supplementation, cervical cerclage, or a combination of both in the prevention of preterm labor (PTL) and their impact on the perinatal outcome.BackgroundPTL is defined as the presence of uterine contractions of sufficient frequency and intensity to effect progressive effacement and dilation of the cervix before term gestation (between 20 and 37 weeks). Preterm delivery occurs in 5-13% of pregnancies before 37 weeks' gestation.Patients and methodsThe present study was designed as a randomized clinical trial. Only 147 women who fulfilled our inclusion criteria (singleton pregnancy and a history of spontaneous PTL, twin or triplet gestations, sonographic cervical length <25 mm in mid trimester, and gestational age at the first antenatal visit of 12-16 weeks) were assigned randomly to the study. Forty-nine women received vaginal progesterone, 49 women were subjected to cervical cerclage, and 48 women received vaginal progesterone and cerclage.The primary outcome parameter was spontaneous delivery at less than 37 weeks' gestation. The secondary outcome parameter was spontaneous delivery at 34 or less weeks' gestation. The neonatal morbidity parameters were birth weight, Apgar score, and neonatal intensive care unit admission.ResultsThe primary and secondary outcome parameters were significantly improved in the combination group (P = 0.005 and 0.008, respectively); also, the neonatal morbidity parameters (birth weight, Apgar score, and neonatal intensive care unit admission) were significantly improved in the combination group (P = 0.047, 0.003, and 0.002, respectively).ConclusionThe combination of vaginal progesterone and cerclage was found to be significantly more effective in preventing PTL and in improving the perinatal outcomes in the high-risk groups.

The clinical utility of sonographic cervical length in the management of preterm parturition at 28–32 weeks of gestation

Objectives: The aim of this study was to evaluate the role of cervical length measurement in early third trimester (28–32 weeks) as a predictor of preterm delivery (PTD), in women presenting with preterm parturition.Methods: Cervical length was measured prospectively, in singleton pregnancies at 28–32 weeks with preterm contractions (PTC). A multivariate linear regression model was performed to assess the association between cervical length and gestational age at delivery. Logistic regression analysis with PTD before 34 and 37 weeks of gestation as the outcome variable was performed to control for confounders.Results: Fifty-six women were included, mean gestational week at presentation and at delivery were 29.88 ± 1.13 and 37.05 ± 2.86, respectively. There was a direct association between short cervical length at admission and gestational week at delivery (p = 0.027). This association remained significant even after controlling for confounders. Short cervical length was significantly associated with PTD before 34 (p = 0.045) or 37 (p = 0.046) weeks of gestation.Conclusions: Third trimester cervical length measurement in patients with PTC is associated with gestational week at delivery, as well as PTD prior to 34 and 37 weeks of gestation. Therefore, examining cervical length is clinically valuable and probably cost-effective during early third trimester.

843: In the presence of premature contraction, which exam is more predictive of premature birth – bishop score or sonographic cervical length?

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality. The prediction of PTB in patients presenting with premature contractions (PC) is limited. In this study, we compared the predictive value of sonographic cervical length (CL) measurement to digital examination of the cervix (Bishop-score - BS), in patients with PC and intact membranes.

Correlation of cervical length, fetal fibronectin, phIGFBP-1, and cytokines in spontaneous preterm birth up to 14 days from sampling.

The aim of this study was to determine the relationship between sonographic cervical length, fetal fibronectin (fFN), phIGFBP-1 (actim partus test), cytokines (IL-6, IL-2R, and TNF-α), and spontaneous preterm birth (SPTB) up to 14 days from sampling. Fifty-eight patients were recruited in a period of 6 months from September 2013 until March 2014 with symptoms or complaints suggestive of preterm labor. Consenting women were treated according to usual hospital protocol, with addition of vaginal swabs taken for fetal fibronectin, phIGFBP-1 (actim partus test) and cervical IL6, IL2R, and TNF-α. The outcome variable was occurrence of preterm delivery within 14 days from the day of hospital admission. Thirty-six patients (62.07%) were delivered within 14 days from admission. Our results indicated that the cervical length significantly inversely correlates with the concentration of IL-6 in the CVF (Spearman's coefficient R=-0.382, P<0.05). Cervical length also correlated with a positive phIGFBP-1 test, i.e., patients with a positive test had an average cervical length of 18.5±4.63 mm, which is significantly lower than patients with a negative test -23.43±7.39 mm (P=0.003). The studied biochemical markers were only moderately successful in the prediction of preterm delivery.

Vaginal progesterone in women with twin gestations complicated by short cervix: a retrospective cohort study.

To determine whether the use of vaginal progesterone in twin gestations with a cervical length (CL) of ≤2.5 cm is associated with a reduced risk of preterm delivery. Retrospective cohort study. Tertiary-care medical centre in New York City. Women with twin gestations undergoing sonographic cervical length screening. Women with twin gestations with a CL of ≤2.5 cm between 16 and 32 weeks of gestation, and who delivered at our centre between 2010 and 2013, were included. We evaluated the impact of vaginal progesterone on the risk of preterm delivery using a Cox proportional hazard model, adjusted for potential confounding factors. We then performed a propensity score analysis using inverse probability of treatment weights to account for treatment selection bias and confounding. Delivery prior to 35 weeks of gestation. Of the 167 twin pregnancies analysed, 61 (35.7%) were treated with vaginal progesterone. The hazard ratio (HR) of delivery prior to 35 weeks of gestation in the vaginal progesterone group, compared with the no vaginal progesterone group, was 1.8 (95% confidence interval, 95% CI 1.5-3.1) in the unadjusted analysis, 1.4 (95% CI 0.7-3.2) following multivariable adjustment for confounding factors, and 1.5 (95% CI 1.1-2.3) using propensity score methods. Women with more risk factors for preterm delivery were more likely to be treated with vaginal progesterone. After statistically correcting for this with propensity score methods, we found that vaginal progesterone therapy in twin pregnancies with a CL ≤2.5 cm was associated with an increased risk of preterm delivery.

The role of sonographic cervical length in labor induction at term.

The purpose of this study is to review the literature examining the role of ultrasound in the induction of labor. Databases including Ovid, PubMed, Web of Science, Google Scholar, and UpToDate were searched and current guidelines from the SOGC, the ACOG, the RCOG, and the RANZCOG were reviewed. Although studies have not demonstrated the superiority of cervical sonography to the Bishop score, the evidence indicates that sonography could be useful in planning induction of labor, significantly reducing the need for cervical ripening agents. A more comprehensive method integrating both sonography and digital exam may be more appropriate.

Can measurement of cervical length, fetal head position and posterior cervical angle be an alternative method to Bishop score in the prediction of successful labor induction?*

Aim: The purpose of this study was to evaluate sonographic cervical length, posterior cervical angle and fetal head position in predicting successful induction of labor at term can be an alternative method to Bishop score. Methods: This prospective observational study recruited 223 women with singleton gestations scheduled for induction of labor at 37–42 weeks. Parity, body mass index, Bishop score, fetal head position, cervical angle measurement and cervical length was investigated to predict successful labor induction. Multiple regression analysis was performed to determine the parameters in the prediction of successful vaginal delivery within 24 hours. Results: Forty-five patients were excluded because of cesarean section performed for other reasons than arrest of dilation or fetal head descent (43 fetal distress, 2 cord prolapsus). Remaining 178 patients were divided into two groups according to duration of delivery time. 139 patients delivered within 24 hours were classified as group I, 39 patients delivered after 24 hours were classified as group II. Percentage of multiparity was statistically significantly higher in group I than in group II [59 (42.4%), 9 (23.0%) respectively, p = 0.009]. Cervical length was statistically significantly shorter in group I than in group II [23.1 ± 7.42 mm, 31.3 ± 6.83 mm respectively, p < 0.001]. Bishop score was statistically significantly higher in group I than in group II [3 (1–4), 1 (1–4) respectively, p < 0.001]. Posterior cervical angle was statistically significantly higher in group I than in group II [100.1 ± 17.2, 92.7 ± 21.4 respectively, p = 0.007]. According to the fetal head position, there was no statistically significant difference in labor duration between the groups (p = 0.787). In the multivariate regression analysis of variables, multiparity, cervical length and Bishop score were statistically significantly predictive in successful labor induction. Conclusion: Multiparity status, cervical length, posterior cervical angle and Bishop score can predict successful labor induction, but fetal head position is not predictive in successful labor induction.