Uterocervical Angle Measurement Research Articles

Utero-cervical angle to predict the risk of spontaneous preterm birth: a review of literature.

The aim of this paper was to evaluate the predictive role of the uterocervical angle (UCA) in spontaneous preterm birth (sPTB). A systematic review of the literature was performed including all studies reporting the association between UCA and sPTB. Searches were performed with the use of a combination of keywords: "cervical length," "uterocervical angle," and "preterm birth" from inception of each database to March 2022. The statistical evaluations were carried out using the Comprehensive Meta-Analysis version 3 (Biostat Inc. USA). Sixteen studies all conducted on the second trimester UCA as well as its association with sPTB were included in this study. In all studies the measurements of cervical length (CL) and UCA were performer in the second trimester, except in one that in the third trimester. In most studies the CL is greater than 30 mm and the UCA is greater than 110 °. In seven studies women with symptoms were considered while in 8 studies the women were asymptomatic. It is too early for it to reach a firm conclusion on UCA utilization in clinical settings. A higher UCA measurement (greater than 150°) is an important risk factor for deliveries before 37 weeks' gestation. It provides a higher diagnostic performance in high risk patients than the CL measurement. However, the most relevant ultrasound parameter for the prediction of delivery within the next few data in women with preterm delivery remains the cervical length. There is a need to consider both markers and create protocols so that the values obtained with UCA and those with CL can make a real contribution to decisions to be made rather than using only CL.

Assessment of utero-cervical angle and cervical length as predictors for threatened preterm delivery in singleton pregnancies.

The aim of this study was to evaluate the relationship between the cervix and the threat of preterm labor in singleton pregnancies between gestational weeks less than 37 and greater than 37 weeks in correlation with utero-cervical angle (UCA) and cervical length (CL) measurements. We conducted a prospective cohort study with UCA and CL measurements in patients with threatened preterm labor (TPL). Primary outcome was differences in UCA and CL measurements in relationship to maternal characteristics and perinatal outcome between groups. Secondary outcome evaluated measurement results and influencing factors for delivery within 7 days, between 1 and 4 weeks and beyond 4 weeks. Overall 152 patients were divided into as study/preterm group (<37 weeks; n = 56) and the control/term group (≥37 weeks; n = 96). Mean gestational age at admission was similar in both groups (30.98 ± 2.83 vs. 30.36 ± 2.63 weeks, p = 0.149) with similar CL (33.9 ± 6.34 vs. 32.02 ± 8.88 mm, p = 0.132), but wider UCA in the preterm group (81.65 ± 16.81° vs. 99.21 ± 22.33°, p < 0.001). Multivariate logistic regression analysis for preterm delivery was significant for nulliparity and UCA measurement. The factor for delivering before 37 gestational weeks within 7 days was the gestational week at admission (p = 0.046). UCA and CL measurements were statistically significant for distinguishing patients for delivery within 7 days and beyond 4 weeks (p = 0.001 for CL and p = 0.0001 for UCA). NPV was found 92.5, 92.2, and 92.3 for UCA >105°, CL ≤30 mm, and Bishop score >3, respectively. Combined measurement of TV UCA and CL represents stronger predictors for sPTB ultrasonographically, demonstrating the uterocervical sub-segment maturation before the active onset of labor.

The predictive role of second trimester uterocervical angle measurement in obstetric outcomes.

Objective:Uterocervical angle has been suggested as a marker to predict preterm birth. However, the literature has limited data about its predictive role in preterm delivery. Moreover, no evidence is present to clarify the role of second-trimester uterocervical angle in induction success and postpartum hemorrhage. Here, it was aimed to compare the role of uterocervical angle with cervical length in predicting preterm labor and assess the utility of the second-trimester uterocervical angle in induction success and postpartum hemorrhage.Materials and Methods:A total of 125 pregnant women, hospitalized with a diagnosis of preterm labor were included in the study. Sonographic measurements of cervical length and uterocervical angle were performed between 16 and 24 weeks of gestation. The demographic, obstetric, laboratory, and sonographic features of the participants were recorded. Patients were divided into subgroups as preterm and term; with and without induction success; with and without postpartum hemorrhage. Additionally, preterm cases were divided into subgroups as early and late preterm. Variables were evaluated between the groups.Results:Cervical length was shorter in the preterm group (30.74±6.37 and 39.19±5.36, p<0.001). The uterocervical angle was 100.85 (85.2-147) in preterm and 88 (70-131) degrees in terms that were statistically significant (p<0.001). Furthermore, the uterocervical angle was wider [126 (100.7-147) and 98 (85.2-114), p<0.001] in the early preterm group. When the groups with and without postpartum bleeding were compared, no significant difference was detected in terms of uterocervical angle [96.5 (71-131) and 88 (70-147), p=0.164]. Additionally, the uterocervical angle was wider in the successful induction group (p<0.001). An a uterocervical angle >85 degrees predicted preterm delivery with 100% sensitivity and 45.54% specificity [area under the curve (AUC)=0.743, p<0.001]. When the cervical length and uterocervical angle were evaluated together to predict preterm delivery, no significant difference was found (p=0.086). An a uterocervical angle >88 degrees predicted induction success with 84.78% sensitivity and 79.75% specificity (AUC=0.887, p<0.001).Conclusion:Our study revealed that the uterocervical angle can be a useful marker in predicting preterm labor and induction success, although it does not predict postpartum hemorrhage.

Measurement of the uterocervical angle for the prediction of preterm birth in symptomatic women

PurposeTo examine if the uterocervical angle (UCA) can be used to predict preterm delivery in women with painful and regular uterine contractions and a cervical length of 25 mm or less.MethodsRetrospective study at the perinatal unit of the University Hospital of Tuebingen, Germany. Women with singleton gestation and preterm contractions between 24 + 0 and 33 + 6 weeks’ gestation were included. For the UCA measurement, a line is placed from the internal os to the external os irrespective of whether the cervix is straight or curved. A second line is drawn to delineate the lower uterine segment. The angle between the two lines is the UCA measurement. The measurements were taken on stored images from our database.ResultsThe study consisted of 213 singleton pregnancies. At the time of UCA measurement, median maternal and gestational age was 31.4 years and 29.7 weeks’ gestation. Median gestational age at delivery was 35.3 weeks and the corresponding birth weight 2480 g, respectively. The UCA measurement in women who delivered within 2 days, between 3–7 days and after 7 days was not helpful to distinguish between these three groups [median UCA measurements: 108.5°, 108.0° and 107.3° (Kruskal–Wallis test p = 0.576)]. Uni- and multivariate logistic multiple regression analysis demonstrated that the delivery within 2 days was only dependent on the gestational age and the cervical length at the time of presentation.ConclusionThe measurement of UCA is not useful in predicting preterm birth in the subsequent 7 days after an episode of preterm contractions.

The Efficacy and Efficiency of Uterocervical Angle Measurements to Predict Preterm Labor in Idiopathic Polyhydramnios Patients: A Prospective Cohort Study.

Uterocervical angle measurements in pregnant women with idiopathic polyhydramnios were appraised for their predictive value for spontaneous preterm labor. In this prospective study, we included nulliparous and multiparous pregnant women diagnosed with idiopathic polyhydramnios at 24-28 weeks at our polyclinic; the uterocervical angle and cervical length were measured by transvaginal ultrasound at the time of diagnosis. Routine pregnancy follow-up was done by our team and gestational age at delivery and maternal-fetal outcomes were noted. In total, 24 patients delivered before 37 weeks and 36 patients delivered at 37 weeks or later. Preterm labor subjects had larger UCA values (126.7±12.9° vs. 100.8±16.2°) and term labor patients had larger cervical length values (34.3±4.5 mm vs. 40.6±5.2 mm). In women with idiopathic polyhydramnios, the area under the curve for the uterocervical angle was 0.885 (p<0.001) and it was 0.823 for the cervical length (p<0.001). The uterocervical angle, a sagittal transvaginal cervical image measurement, is a practical method that successfully predicts spontaneous preterm labor risk in singleton pregnancies with idiopathic polyhydramnios. In addition, the uterocervical angle displayed greater sensitivity, but lower specificity, compared with cervical length measures.

Uterocervical angle measurement for preterm birth prediction in singleton pregnant women with no history of preterm birth and normal cervical length: A prospective cohort study

ObjectiveTo evaluate the ability of second trimester uterocervical angle (UCA) to predict spontaneous preterm birth (sPTB) in low-risk singleton pregnant women. Study designTransvaginal sonographies were performed in the second trimester of 450 singleton pregnant women with no history of sPTB and no history of second trimester miscarriage with normal cervical length (CL) who attended antenatal care at Songklanagarind Hospital, a tertiary teaching hospital in southern Thailand. Gestational ages at delivery were recorded then the UCA values were evaluated according to sPTB occurrence. The differences in mean values of UCA between sPTB and full-term groups were evaluated using t-test. A receiver operating characteristics (ROC) curve was used to assess the ability of UCA to predict sPTB. ResultsAfter excluding women with unknown pregnancy outcomes or missing UCA images, the sPTB rate was 34/421 (8.1 %). In women with anteflexed uterus, the mean UCA value was wider in the sPTB group compared to those with term birth if the measurements were performed at GA 19.5–24 weeks (sPTB group, 123.4°vs controls, 104.3°; P = 0.017). The ROC curve showed an area under the curve (AUC) of 0.7045. The optimal UCA cut-off value was ≥110 degrees, which gave a sensitivity of 83.3 % and a specificity of 61.2 %. The positive predictive value (PPV) was 16.7 %, negative predictive value (NPV) 97.5 %, positive likelihood ratio (LR+) 2.2 and negative likelihood ratio (LR-) 0.3. ConclusionThe UCA in the second trimester is not a good predictor of sPTB in low risk pregnant women.

Distribution of uterocervical angles in the second trimester of pregnant women at low risk for preterm delivery

The uterocervical angle (UCA) has recently been studied as a parameter to identify women at risk for spontaneous preterm birth (sPTB). This study aimed to investigate the distribution of UCA values by transvaginal sonography (TVS) in the second trimester of women at low risk for sPTB. TVS was performed in 450 low-risk pregnant women at gestational age (GA) 160/7–240/7 weeks. The UCA distribution by GA was visualised using a scatter plot. The range of UCA values and their relationship with GA were assessed using quantile regression analysis. p < .05 was considered statistically significant. A total of 242 participants with anteflexed uterus, no history of caesarean section and term delivery were analysed. The normal range of UCA (5th and 95th percentiles) was from 63.0 degrees (95% CI, 53.1–72.9) to 148.8 degrees (95% CI, 139.5–158.0) with no significant changes during this GA period (–0.3 degrees per week, p = .757). Impact statement What is already known on this subject? Spontaneous preterm birth (sPTB) is a major problem in obstetrics. A screening strategy using history of sPTB and cervical length (CL) measurement is the current standard to identify women at risk for sPTB and provide adequate prevention. However, a third of women who are identified as low risk go on to have sPTB, so a better means needs to be found to more reliably identify women at risk. Various studies have found that a wide uterocervical angle (UCA) was associated with sPTB, and thus the UCA has been proposed as a potential sPTB screening parameter. However, to date there is a lack of prospective studies evaluating this proposal, and no consensus about the proper gestational age to perform UCA measurements to identify women at risk of sPTB. What do the results of this study add? This study reports the distribution of UCA at the GA of 160/7–240/7 weeks of low-risk singleton pregnancy women who delivered at term. The mid-90% values ranged from 63.0 degrees to 148.8 degrees with no significant differences in this GA period. What are the implications of these findings for clinical practice and/or further research? Because of the wide range of UCA values at GA 160/7–240/7 weeks, more studies regarding UCA values in various gestational ages are required to fully understand the trend of UCA values along pregnancy and confirm whether or not the UCA would be a useful parameter for sPTB prediction and if so at what gestational age it would have to be assessed.

Correlation of transabdominal and transvaginal sonography for the assessment of uterocervical angle at 16–24 weeks’ gestation

The objective of this study was to determine the correlation between transabdominal (TAS) and transvaginal sonography (TVS) uterocervical angle (UCA) measurement in pregnant women with no history of previous preterm birth. A cross-sectional study involving singleton pregnancies between 16 and 24 weeks of gestation who underwent routine foetal anatomical scan was conducted. The TAS-UCA measurement was performed before voiding and with an empty bladder. A total of 256 women completed the sonography. The mean maternal age was 32 ± 6.68 years. The mean gestation age at the time of ultrasound assessment was 19 ± 1.71 weeks. The mean prevoid TAS-UCA was 119.74 ± 33.12° and the mean postvoid TAS-UCA was 110.73 ± 25.30°. There was a significant difference between prevoid and postvoid TAS-UCA measurement (p < .05). The mean TVS-UCA was 103.91 ± 26.42°. The Pearson correlation coefficients of prevoid and postvoid TAS-UCA with TVS-UCA were 0.438 and 0.601, respectively. In conclusion, the postvoid TAS-UCA has moderate correlation with TVS-UCA measurement and is better than the prevoid TAS-UCA in women with low risk for preterm birth.IMPACT STATEMENTWhat is already known on this subject? TVS is the gold standard for cervical length (CL) assessment for prediction preterm birth. However, TVS requires an experienced or trained sonographer and some women decline TVS because of the embarrassment and discomfort during examination. Several studies have demonstrated the correlation between TAS and TVS and suggested that TAS could be an alternative for CL screening. UCA has been reported as a new predictor of spontaneous preterm birth and is usually performed by TVS. Thus, it is interesting to evaluate whether TAS can be a substitute procedure for TVS in UCA measurement.What the results of this study add? TAS may be used as a substitute procedure for TVS and the postvoid TAS is more appropriate than prevoid TAS for UCA measurement.What the implications are of these findings for clinical practice and/or further research? TAS may be an alternative method for UCA measurement when TVS is unavailable or in pregnant women who decline TVS-UCA measurement. However, further study should be conducted to confirm the association between TVS-UCA and postvoid TAS-UCA before deciding to use postvoid TAS-UCA as a screening tool for preterm prediction.

Second trimester uterocervical angle and spontaneous preterm birth in twins

Objective: To determine if there is an association between uterocervical angle (UCA) and spontaneous preterm birth (sPTB) < 37 weeks for women with twins. Materials and methods: Retrospective cohort study from 2014 to 2017 of twin pregnancies with cervical length (CL) screening between 15 0/7 and 24 6/7 weeks. Monochorionic-monoamniotic twins were excluded. Post-hoc UCA measurements were analyzed as a continuous variable and a wide UCA was also defined as an angle >95° and >110°. The primary outcome was sPTB < 37 weeks. Secondary outcomes were sPTB <34 weeks, <32 weeks, CL, and performance metrics for UCA. Binary logistic regression controlled for age, tobacco use, prior sPTB, CL, and gestational age at CL measurement. Results: A total of 114 women were studied. The rate of sPTB <37 weeks was 35.0%, <34 weeks was 21.4%, and <32 weeks was 17.1%. As a continuous variable, mean UCA was 117.9° (SD 27.1°) for delivery ≥37 weeks and 133.1° (SD 23.1°) <37 weeks (p = .002). A wider mean UCA was also associated with sPTB <34 weeks (sPTB ≥34 weeks: 120.9° [SD 26.5°] vs. <34 weeks: 133.0° [SD 22.8°], p = .025) and sPTB <32 weeks (sPTB ≥32 weeks: 121.2° [SD 25.9°] vs. <32 weeks: 135.0° [SD 24.0°], p = .018). However, after controlling for age, prior sPTB, tobacco use, CL measurement, and gestational age at CL measurement, UCA was not associated with sPTB <37 weeks, <34 weeks, or <32 weeks. UCA >110° was associated with sPTB <37 weeks after controlling for confounders (aOR 3.6 [95% CI 1.2–10.5], p = 0.02). There was no association between UCA >110° and sPTB <34 or <32 weeks. Furthermore, a UCA >95° was not associated with sPTB <37, <34, or <32 weeks. As a screening tool for sPTB <37 weeks, a UCA of >110° had a sensitivity of 85.7%, specificity of 43.1%, positive predictive value of 53.2%, negative predictive value of 80.0%, positive likelihood ratio of 1.5, and negative likelihood ratio of 0.3. Conclusions: In a cohort of dichorionic-diamniotic and monochroionic-diamniotic twins, UCA >110° was associated with sPTB <37 weeks. However, second trimester UCA had a low positive likelihood ratio and was not a robust marker for the prediction of sPTB in twins.

Assessment of Uterocervical Angle Width as a Predictive Factor of Preterm Birth: A Systematic Review of the Literature.

Background Uterocervical angle (UCA) has been recently proposed as a potential marker that could accurately predict preterm birth (PTB). The purpose of the present systematic review is to accumulate current evidence and provide directions for future research. Materials and Methods We used the Medline (1966–2018), Scopus (2004–2018), Clinicaltrials.gov (2008–2018), EMBASE (1980-2018), Cochrane Central Register of Controlled Trials CENTRAL (1999-2018), and Google Scholar (2004-2018) databases in our search. Results Eleven studies were finally included in the present systematic review that evaluated data from 3,018 women. The significant heterogeneity in terms of outcome reporting and outcome reporting measures (use of optimal cut-off values) precluded meta-analysis. However, existing data support that second trimester UCA measurement might be used as a predictive factor of PTB <34 weeks, as at least two studies in unselected singleton pregnancies and two studies in pregnancies with an ultrasonographically shortened cervix seem to support this hypothesis. The most commonly reported cut-off values were 105° and 95°. Conclusions UCA measurement during the second trimester of pregnancy may be a useful method of determining women at risk of delivering preterm. However, more studies are needed to assess the reproducibility of these findings and reach conclusive evidence.

P17.03: Uterocervical angle measurement in the prediction of preterm birth in women presenting with threatened preterm labour

P17.03: Uterocervical angle measurement in the prediction of preterm birth in women presenting with threatened preterm labour

Comparison of reliability between uterocervical angle and cervical length measurements by various experienced operators using transvaginal ultrasound

Purpose: To compare the reliability between uterocervical angle (UCA) and cervical length (CL) measurements by various experienced operators.Methods: Transvaginal ultrasonographies (TVS) were performed in 102 pregnant women between 16°/7–24°/7 gestational weeks by different levels of experienced operators. For both CL and UCA measurements, intraobserver variability was assessed for each operator by examining the range between maximum and minimum measurements in each participant, compared to the mean of all three measurements. Interobserver variabilities were explored using Bland–Altman analysis. Intraclass correlation coefficients were used for both intraobserver and interobserver reliability.Results: For intraobserver variability of the UCA, the ranges between maximum and minimum UCA measurements in operator 1 and 3 were 1.5º–34º and 2º–36º (n = 51), and in operators 2 and 3 were 0º–61º and 1º–25º (n = 51). Intraclass correlation coefficients (ICC) for intraobserver reliability were 0.90 for operator 1, 0.67 for operator 2 and 0.93 for operator 3. For interobserver variability of the UCA, the limits of agreement for mean UCA were −37.53º–38.41º and −36.27º–26.17º, and for maximum UCA were −39.47º–41.38º and −44.24º–22.9º in comparisons between operators 1 and 3, and operator 2 and 3, respectively. Intraclass correlation coefficients for mean UCA were 0.73 and 0.74, and for maximum UCA were 0.71 and 0.67 in comparisons between operators 1 and 3, and operator 2 and 3, respectively.Conclusions: The UCA measurements had a higher intra- and interobserver reliabilities than the CL measurements.

Uterocervical angle: an ultrasound screening tool to predict satisfactory response to labor induction

Background: A wide uterocervical angle >95° detected during the second trimester was associated with an increased risk for spontaneous preterm birth.Objective: We aimed to determine whether an ultrasonographic marker, uterocervical angle, correlates with satisfactory response to labor induction.Study design: We conducted a prospective cohort study from May 2016 through December 2017 of singleton term gestations undergoing transvaginal ultrasound for cervical length screening and uterocervical angle measurement. Uterocervical angle was measured between the lower uterine segment and the cervical canal. Latent phase duration >720 min was accepted to be a prolonged latent phase. The primary outcome was a prediction of satisfactory response to labor induction (latent phase duration <720 min).Results: Both anterior uterocervical angle (AUC = 0.802, p < .001) and the cervical length (AUC = 0.679, p < .05) significantly predicted satisfactory response to labor induction. Optimal cutoff value was obtained at the value of 97° (64% sensitivity, 91% specificity) for anterior uterocervical angle and 27 mm (64% sensitivity, 64% specificity) for the cervical length. Kaplan–Meier survival analysis showed that duration from labor induction to delivery was significantly higher in a group with longer cervical length (p = .04), additionally labor induction to delivery time was significantly higher in a group with lower UCA (p = .04).Conclusions: Both the cervical length and anterior uterocervical length were predictors for the satisfactory response to labor induction, and both parameters were found to be significantly associated with time from induction to delivery in survival analysis.

465: Ultrasonographic measurement of uterocervical angle in twins: Predicting spontaneous preterm birth

Uterocervical angle (UCA) is the angle between the lower uterine segment and cervical canal. UCA angles >95° and >105° have been shown to correlate with an increased risk for spontaneous preterm birth (sPTB) in singletons. However, there is no data on the use of UCA for the prediction of sPTB in twins. Our objective was to determine the relationship between UCA and risk of sPTB <37wks in twins. We performed a retrospective study from 2014-2017 of twins who underwent CL screening at a major urban university hospital. Women who had at least one CL between 14 to 24 6/7 wks were included. Monochorionic monoamniotic twins were excluded. Post-hoc UCA measurements were obtained using methods described by Dziadosz et al. Wide UCA was defined as an angle >95° and >105°. The primary outcome was the risk of sPTB at <37wks. Secondary outcomes were sPTB<32wks and performance metrics. 137 women were studied (118 (86.1%) dichorionic diamniotic and 19 (13.9%) monochorionic diamniotic). Median gestational age was 18.0wks (IQR 17.0-19.0wks) and median CL was 3.7cm (IQR 3.2-4.2cm). 7.3% of women had a CL<2.5cm. 52.6% of women had a sPTB <37wks and 19.0% <32wks. The median UCA was 124.0° (IQR 104.5-142.5°). UCA > 95° and >105° were both associated with an increased risk of sPTB<37wks (55.9% vs 31.6%, p=0.05 and 58.3% vs 35.3%, p=0.02, respectively). There was a trend between UCA >95° and >105° and increased risk of sPTB<32wks. In the subgroup of women with dichorionic twins, UCA > 95° and >105° was associated with a trend towards an increased risk of sPTB<37wks, although this did not reach statistical significance. (table 1) Evaluating performance metrics, UCA was a better screening test and was not improved with the addition of CL<2.5cm. (table 2). A UCA >95° and >105° was associated with an increased risk of sPTB <37wks in twins. These findings enhance our understanding of the cervical changes associated with sPTB. As a screening tool in twins, second trimester UCA outperformed CL for the prediction of sPTB <37 wks.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Uterocervical Angle Measurement Improves Prediction of Preterm Birth in Twin Gestation.

Twin pregnancies are associated with an increased risk of spontaneous preterm birth. Our objective was to compare the performance of uterocervical angle to cervical length as predictors of spontaneous preterm birth in this population. We conducted a retrospective cohort study of twin gestations at a single center from May 2008 to 2016 who received a transvaginal ultrasound for the evaluation of the cervix between 16 0/7 and 23 0/7 weeks. The primary outcome was prediction of preterm birth <28 and <32 weeks by uterocervical angle and cervical length. Among 259 women with twin gestation, the mean gestational age at birth was 34.83 ± 3.48 weeks. Receiver operator characteristic curves demonstrated optimal prediction of spontaneous preterm birth prior to 32 weeks at a uterocervical angle >110° (80% sensitivity, 82% specificity) [odds ratio (OR), 15.7 (95% confidence interval (CI), 7.2-34.4)] versus cervical length <20 mm (53% sensitivity, 85% specificity; p < 0.001, OR, 6.4 [95% CI, 2.3-17.8]) and similarly, prior to 28 weeks at a uterocervical angle >114° (OR, 24.3 [95% CI, 6.7-88.5]) compared with cervical length <20 mm (OR, 11.4 [95% CI, 3.5-36.7]). Uterocervical angles >110° performed better than cervical length for the prediction of spontaneous preterm birth in twin gestations.

The uterocervical angle and its relationship with preterm birth

Objectives: The objective of this study is to determine whether the uterocervical angle (UCA) correlates with the risk of spontaneous preterm birth (sPTB) < 34 weeks and assess its interobserver variability.Study design: Case–control study of 275 women including 34 who started labor spontaneously and gave birth before 34 weeks of gestation (preterm group) and 241 who gave birth at term (control group). Images used to report cervical length were re-measured for UCA.Results: Mean UCA in the second trimester was wider in the preterm group (105.16°) compared with the control group (94.53°), p = .015. The intraclass correlation coefficient was 0.821 (95% CI: 0.74–0.97) for masked interobserver variability, which implies correct agreement among UCA measurements. Mean UCA increased from the first to the second trimester (84.2° versus 94.5°; p = .019).Conclusions: Wider UCA in the second trimester is related to sPTB. UCA measurement is a reproducible technique. UCA appears to increase from the first to the second trimester. Prospective studies, with ultrasound examinations aimed at measuring UCA in vivo, are needed to accurately assess the characteristics of this marker and its potential as a predictor of sPTB in clinical practice.

350: Preterm birth prediction with transvaginal cervical length and uterocervical angle measurements

To assess the performance of transvaginal cervical length (CL) and uterocervical angle (UCA) for predicting preterm birth (PTB) <37 weeks gestation. This is a retrospective cohort study of nulliparas with singleton gestations who underwent a routine transvaginal CL measurement between 18-23 6/7 weeks and delivered at a single tertiary center from July 2011-January 2014. For each woman with a short cervix (defined as a CL ≤25mm), 4 women without a short cervix were randomly selected from the remainder of the overall cohort, and together these women served as the study population. Sonographic images were reviewed and UCA was measured. Receiver operating characteristic (ROC) curves for the outcome of PTB <37 weeks were generated for CL and UCA as continuous measures, and the areas under the curves (AUCs) were compared. Based on cutoffs established in the existing literature, UCA was then dichotomized at 95 degrees. ROC curves for the outcome of PTB <37 weeks were generated for CL ≤25mm and UCA ≥95 degrees, and the AUCs were compared. Lastly, a ROC curve examining the prediction of PTB in women with either a CL ≤25mm or UCA ≥95 degrees was generated and the AUC was compared to each measure alone. A total of 405 women were included, of whom 81 (20%) had a short cervix, 204 (50.4%) had UCA ≥95 degrees, and 222 (54.8%) had either a short cervix or UCA ≥95 degrees. The AUCs for the ROC curves evaluating the predictive value of CL and UCA as continuous measures for PTB <37 weeks were not significantly different (0.72, 95% CI 0.63-0.80 vs. 0.66, 95% CI 0.57-0.75, p=0.27). Similarly, the AUCs for the ROC curves for CL ≤25mm and UCA ≥95 degrees were not significantly different (0.67, 95% CI 0.60-0.74 vs. 0.62, 95% CI 0.55-0.69, p=0.21). The AUC for women with either a CL ≤25mm or UCA ≥95 degrees was no better than that of a short cervix alone (AUC 0.64, 95% CI 0.58-0.70, p=0.32) (Figure). UCA has a similar predictive capability to CL for the prediction of PTB. Their combination does not significantly improve PTB prediction in nulliparas with singleton gestations.

130: Uterocervical angle measurement improves prediction of preterm birth in twin gestation

An obtuse uterocervical angle (UCA) has been associated with increased risk of preterm birth in singleton gestations. Our objective was to compare the performance of UCA to cervical length (CL) as sonographic predictors of spontaneous preterm birth (sPTB) in patients with twin gestation. We conducted a retrospective cohort study of twin gestations at a single academic center from May 2008-2016 who received a transvaginal ultrasound for the evaluation of the cervix between 16 0/7 - 22 6/7 weeks. An investigator blinded to clinical outcomes reviewed images of cervical morphology and measured UCA and CL parameters. Data on obstetrical outcomes was extracted from the medical record. The primary outcome was prediction of preterm birth <28 weeks and <32 weeks by UCA and CL. Receiver operator characteristic (ROC) curves and binary logistic regression were used for statistical analysis. Statistical significance was defined as p <0.05. Among 259 women with twin gestation, the mean gestational age at birth was 34.83 +/- 3.48 weeks, and 44.7% (n=116) delivered prior to 36 weeks. ROC curves demonstrated optimal prediction of sPTB prior to 32 weeks at a UCA > 110o (80% sensitivity, 82% specificity) vs. CL < 25mm (27% sensitivity, 93% specificity; p<0.001) and similarly, prior to 28 weeks at a UCA>114o (80% sensitivity, 84% specificity) vs. CL< 25mm (35% sensitivity, 90% specificity; p<0.001, Figure). Binary logistic regression revealed UCA > 110o conferred an OR 15.7 (95% CI 7.2-34.4) for delivery prior to 32 weeks, and UCA > 114o an OR 24.3 (95% CI 6.7-88.5) for delivery prior to 28 weeks. In comparison, CL<25mm had an OR 5.2 (95% CI 2.2-12.2) and OR 6.0 (95% CI 2.0-18.1) prior to 32 and 28 weeks respectively. Uterocervical angles >110o performed better than the traditional cervical length threshold (25mm) for the prediction of sPTB in a cohort of twin gestations. Measurement of the UCA during the mid-trimester may improve identification of twin gestations at risk for sPTB.

131: Uterocervical angle measurement improves prediction of latency to delivery in patients with cerclage

131: Uterocervical angle measurement improves prediction of latency to delivery in patients with cerclage