Ultrasound Measurement Of Cervical Length Research Articles

Comparison of trans-vaginal ultrasound cervical length measurement and Bishop score in predicting successful labour induction in term pregnancies at Ahmadu Bello University Teaching Hospital Zaria

The goal of induction of labour (IOL) is to achieve successful vaginal delivery and reduce caesarean section (CS). The gold standard method for assessing cervical status has been the use of the Bishop score (BS) which is not flawless leading to unnecessary intervention. Trans-vaginal ultrasound cervical length (CL) measurement has been compared with BS in predicting successful IOL. The objective of this study was to compare CL and BS in predicting successful IOL at Ahmadu Bello University Teaching Hospital. It was a cross sectional comparative study design conducted among pregnant women at 37-42 weeks of gestation slated for IOL between November 2017 to November 2018. Eighty-seven (87) women were recruited as participants. Each participant, had a trans-vaginal ultrasound (TVS) CL measured and each was followed by a digital cervical assessment using BS. Relevant data obtained was analysed using SPSS version 23. The significance level was considered at P< 0.05 IOL was successful in 66.2% (47) of the participants, while 15% (13) had CS. The receiver operating characteristic curve (ROC) demonstrated a better performance of the BS (AUC= 0.556, P= 0.433, CI= 0.426-0.673, PPV=52.8%) in predicting successful IOL than the TVS-CL measurement (AUC= 0.446, P=0.391, CI= 0.317-0.574) PPV=60.2%). Results further showed that the best cut off values for favourability for IOL for TVS-CL and BS were ≤2.5 cm and ≥5 respectively. The most important component of the BS predictive of successful IOL was cervical dilatation (OR= 0.603, P=0.011). TVS-CL did not demonstrate a diagnostic accuracy in predicting successful IOL in term pregnancies compared to BS.

Screening and prevention of preterm birth: how is it done in clinical practice?

To ascertain how screening for preterm birth is performed among obstetricians working in public and private practice in a middle-income country. Cross-sectional study of 265 obstetrician-gynecologists employed at public and private facilities. An online questionnaire was administered, with items designed to collect data on prematurity screening and prevention practices. The mean age of respondents was 44.5 years; 78.5% were female, and 97.7% had completed a medical residency program. Universal screening (i.e., by ultrasound measurement of cervical length) was carried out by only 11.3% of respondents in public practice; 43% request transvaginal ultrasound if the manual exam is abnormal, and 74.6% request it in pregnant women with risk factors for preterm birth. Conversely, 60.7% of respondents in private practice performed universal screening. This difference in screening practices between public and private practice was highly significant (p < 0.001). Nearly all respondents (90.6%) reported prescribing vaginal progesterone for short cervix. In the setting of this study, universal ultrasound screening to prevent preterm birth was used by just over half of doctors in private practice. In public facilities, screening was even less common. Use of vaginal progesterone in cervical shortening was highly prevalent. There is an unmet need for formal protocols for screening and prevention of preterm birth in middle-income settings.

Transperineal ultrasound measurement of cervical length to predict preterm delivery in women with threatened preterm labour

Transperineal ultrasound measurement of cervical length to predict preterm delivery in women with threatened preterm labour

Changes of uterocervical angle and cervical length in early and mid-pregnancy and their value in predicting spontaneous preterm birth.

Objective: To explore the feasibility of transvaginal ultrasound measurement of uterocervical angle (UCA) and cervical length (CL) in early and mid-pregnancy and evaluate their combined prediction of spontaneous preterm birth (sPTB) in singleton pregnancies. Patients and Methods: This retrospective study comprised 274 pregnant women who underwent transvaginal ultrasound measurement of CL in mid-pregnancy (15-23+6weeks); in 75 among them, CL also had been measured in early-pregnancy (<14 weeks). These 274 pregnant women were further divided into a preterm group (n = 149, <37weeks gestation) and a control group (n = 125, >37weeks gestation) according to delivery before or after 37weeks, respectively. In the preterm group, 35 patients delivered before 34weeks and the remaining 114 delivered between 34 and 37weeks. Results: The optimal threshold of CL to predict preterm birth risk in women with <37weeks gestation was 3.38cm, and the optimal threshold of the UCA to predict preterm birth risk in the same group of women was 96°. The optimal threshold of CL to predict preterm birth risk in women with <34weeks gestation was 2.54cm, while that of the UCA in the same group of patients was 106°. The area under the curve for predicting preterm birth by combining the UCA and CL measurements was greater than that by using the UCA or CL alone (p < 0.01). The sensitivity and specificity for predicting preterm birth at <34 weeks gestation was 71.7% and 86.4%, respectively; and the sensitivity and specificity for predicting preterm birth at <37weeks gestation was 87.6% and 80.6%, respectively. The difference between the two groups in CL and UCA were not significant in early pregnancy (p > 0.01), but only in mid-pregnancy (p < 0.01). There was a negative correlation between UCA and gestational week at delivery (r = -0.361, p < 0.001) and a positive correlation between CL and gestational week at delivery (r = 0.346, p < 0.001) in mid-pregnancy. The proportion of deliveries at <34 weeks was highest when the UCA was >105°, and the proportion of deliveries between 35 and 37weeks was highest when the UCA was between 95° and 105°. The proportion of deliveries at <34weeks was highest when the CL was <2.5cm. Conclusion: The combination of UCA and CL has a better ability to predict preterm birth than either measurement alone. A more obtuse UCA or a shorter CL is associated with an earlier spontaneous preterm birth. The UCA increases from early to mid-pregnancy, while the CL decreases from early to mid-pregnancy.

A multivariable prediction model for intra-amniotic infection in patients with preterm labor and intact membranes including a point of care system that measures amniotic fluid MMP-8.

Among patients with preterm labor and intact membranes (PTL), those with intra-amniotic infection (IAI) present the highest risk of adverse perinatal outcomes. Current identification of IAI, based on microbiological cultures and/or polymerase chain reaction amplification of the 16S ribosomal RNA gene, delay diagnosis and, consequently, antenatal management. The aim to of the study was to assess the performance of a multivariable prediction model for diagnosing IAI in patients with PTL below 34.0weeks using clinical, sonographic and biochemical biomarkers. From 2019 to 2022, we prospectively included pregnant patients admitted below 34.0weeks with diagnosis of PTL and had undergone amniocentesis to rule in/out IAI. The main outcome was IAI, defined by a positive culture and/or 16S ribosomal RNA gene in amniotic fluid. Based on the date of admission, the sample (n=98) was divided into a derivation (2019-2020, n=49) and validation cohort (2021-2022, n=49). Logistic regression models were developed for the outcomes evaluated. As predictive variables we explored ultrasound cervical length measurement at admission, maternal C-reactive protein, gestational age, and amniotic fluid glucose and matrix metalloproteinase-8 (MMP-8) levels. The model was developed in the derivation cohort and applied to the validation cohort and diagnostic performance was evaluated. Clinical management was blinded to the model results. During the study period, we included 98 patients admitted with a diagnosis of PTL. Of these, 10 % had IAI. The final model included MMP-8 and amniotic fluid glucose levels and showed an area under the receiver operating characteristic curve to predict the risk of IAI of 0.961 (95 % confidence interval: 0.860-0.995) with a sensitivity of 75 %, specificity of 93.3 %, positive likelihood ratio (LR) of 11.3 and negative LR of 0.27 in the validation cohort. In patients with PTL, a multivariable prediction model including amniotic fluid MMP-8 and glucose levels might help in the clinical management of patients undergoing amniocentesis to rule in/out IAI, providing results within a few minutes.

Longitudinal change in cervical length following vaginal or abdominal cervical cerclage: a randomized comparison

Cervical cerclage has been shown to reduce the risk of recurrent spontaneous preterm birth in a high-risk patient population; however, the mechanism is not well understood. Transabdominal cerclage is superior to low and high vaginal cerclage in reducing early spontaneous preterm birth and fetal loss in women with previous failed vaginal cerclage. Cervical length measurements are commonly used to monitor high-risk women and may explain the mechanism of success. This study aimed to evaluate the rate of change in longitudinal cervical length after randomized placement of low transvaginal, high transvaginal, or transabdominal cerclage in women with a previous failed vaginal cerclage. This was a planned analysis of longitudinal transvaginal ultrasound cervical length measurements from patients enrolled in the Vaginal Randomised Intervention of Cerclage trial, a randomized controlled trial comparing transabdominal cerclage or high transvaginal cerclage with low transvaginal cerclage. Cervical length measurements at specific gestational ages were compared over time and between groups, using generalized estimating equations fitted using the maximum-likelihood random-effects estimator. In addition, cervical length measurements were compared in women with transabdominal cerclage placed before and during pregnancy. The diagnostic accuracy of cervical length as a predictor of spontaneous preterm birth at <32 weeks of gestation was explored. This study included 78 women who underwent longitudinal cervical length assessment (70% of the analyzed cohort) with a history of failed cerclage, of whom 25 (32%) were randomized to low transvaginal cerclage, 26 (33%) to high transvaginal cerclage, and 27 (35%) to transabdominal cerclage. Abdominal cerclage was superior to low (P=.008) and high (P=.001) vaginal cerclage at maintaining cervical length over the surveillance period (14 to 26 weeks of gestation) (+0.08 mm/week, 95% confidence interval, -0.40 to 0.22; P=.580). On average, the cervical length was 1.8 mm longer by the end of the 12-week surveillance period in women with transabdominal cerclage (+1.8 mm; 95% confidence interval, -7.89 to 4.30; P=.564). High vaginal cerclage was no better than low cervical cerclage in the prevention of cervical shortening; the cervix shortened by 13.2 mm over 12 weeks in those with low vaginal cerclage (95% confidence interval, -21.7 to -4.7; P=.002) and by 20 mm over 12 weeks in those with high vaginal cerclage (95% confidence interval, -33.1 to -7.4; P=.002). Preconception transabdominal cerclage resulted in a longer cervix than those performed during pregnancy; this difference was significant after 22 weeks of gestation (48.5 mm vs 39.6 mm; P=.039). Overall, cervical length was an excellent predictor of spontaneous preterm birth at <32 weeks of gestation (receiver operating characteristic curve, 0.92; 95% confidence interval, 0.82-1.00). In women with a previous failed cervical cerclage, in the next pregnancy, the cervical length in women treated with vaginal cerclage funneled and shortened over time, whereas there was preservation of cervical length in women who receive transabdominal cerclage. Cervical length remained longer in transabdominal procedures performed before pregnancy than in transabdominal procedures performed during pregnancy. Overall, cervical length was an excellent predictor of spontaneous preterm birth in our cohort. Our findings may explain the mechanism of benefit for transabdominal cerclage, with its high placement better maintaining the structural integrity of the cervix at the level of the internal os.

The use of fetal fibronectin and cervical length measurements in the prediction of spontaneous preterm birth in women with an Arabin pessary in situ

ObjectivesThe ability to predict spontaneous PTB (sPTB) has improved greatly, allowing women at risk to be managed with prophylactic interventions such as cervical cerclage and the Arabin pessary. Cervicovaginal fetal fibronectin (qfFN) concentration and ultrasound measurement of cervical length (CL) are the two most established tools to predict sPTB. There is however limited data regarding the predictive value of qfFN and CL tests following insertion of an Arabin pessary. Our aim was therefore to determine the clinical use of qfFN and CL measurements to predict sPTB in women fitted with an Arabin pessary. Study designThis study is a secondary analysis on the SUPPORT trial data. Data were prospectively collected from women attending high-risk preterm surveillance clinics in 3 London centres between July 2015 and April 2020. The matched control group was pregnant women attending the same high-risk preterm surveillance clinics who had not received an Arabin pessary. Receiver operating characteristic (ROC) curves for prediction of birth by 34 and by 37 weeks’ gestation were generated for qfFN and CL measurements combined for both study groups. A formal comparison of area under the curve before 34 weeks’ gestation (AUC < 34 weeks) was made between the two study groups. ResultsAt our primary endpoint of sPTB < 34 weeks' gestation, qfFN was a good predictor of sPTB in cases with an Arabin pessary in situ (AUC, 0.79, 95% CI: 0.62–0.90) and no worse than the control group who did not have an Arabin pessary, (AUC 0.74, 95% CI: 0.48–0.96). CL had good prediction for sPTB < 34 weeks’ gestation in the control group (AUC 0.76, 95% CI: 0.63–0.88) but was lower and non-significant in the Arabin pessary case group (AUC 0.60, 95% CI: 0.43–0.76). ConclusionsThis study showed that cervicovaginal qfFN concentration is equally reliable in the prediction of sPTB in pregnant women at increased risk of sPTB with and without an Arabin pessary in situ, and significantly better than CL measurement alone for predicting delivery before 34 weeks. This commonly used test therefore has utility in predicting sPTB in pregnant women fitted with an Arabin pessary.

Consistency in the transabdominal ultrasound measurement of cervical length in mid-pregnancy.

The Western Australian Preterm Birth Prevention Initiative recommends a transabdominal cervical length (TACL) measurement at the mid-pregnancy ultrasound to screen low-risk women for preterm birth risk. In view of this recommendation, we assessed the inter-observer consistency of TACL screening in mid-pregnancy. Routinely collected mid-pregnancy TACL ultrasound images were graded from 0 to 4 according to the anatomical landmarks identified by a single expert. A random selection of 10 images of each grade were disseminated in an electronic survey to determine inter- and intra-observer variations in the classification of the cervical image. A total of 244 participants graded 50 TACL images. Six participants repeated the grading. Overall agreement to the exact initial grade for all images was 49.6%, highest for images at both ends of the spectrum (83% Grade 0 and 70.4% for Grade 4). Overall agreement to the initial diagnostic Grades 3 and 4 was 75.3% (95% CI 74.5-76.0%) and was higher when the maternal bladder was empty. There was moderate inter-rater agreement (κ = 0.42) for Grades 3 and 4 (diagnostic) or Grades 1 and 2 (non-diagnostic). The intra-rater agreement was fair to good (κ = 0.59, 95% CI 0.49-0.70) for those who repeated the assessment (including the expert grader). Sonographic CL screening is considered an important tool for the identification of women at high risk of preterm birth. Image classification of TACL performed poorly compared with previous studies assessing transvaginal cervical length. Improved reliability and measurement consistency may be achieved through high levels of quality assurance, ongoing training and image audit.

VP46.11: Transperineal ultrasound cervical length measurement in preterm labour

VP46.11: Transperineal ultrasound cervical length measurement in preterm labour

PREDICTION OF PROLONGED PREGNANCY IN NULLIPAROUS WOMEN BY TRANSVAGINAL ULTRASOUND MEASUREMENT OF CERVICAL LENGTH AT 37 WEEKS OF PREGNANCY

Background: Prolonged pregnancy occurs in approximately 10% of all singletone pregnancy and is associated with an increased risk of foetal macrosomia, intrapartum fetal cardiac abnormalities, meconium staining, perinatal death, and cesarean delivery. Objective: To detect the relationship between transvaginal ultrasound measurement of cervical length at 37 weeks of pregnancy and prolonged pregnancy in nullipara. Patients and Methods: This was a prospective study of women attending Mataria teaching hospital was conducted from January 2019 to December 2019. The study included 120 women at 37 weeks of gestation observed till time of delivery. Gestational age was determined from the menstrual history and confirmed by an ultrasound scan and measurement of the crown–rump length in the first trimester, or the head circumference in the second trimester. Results: This study showed that cervical length at weeks can predict the likelihood of prolonged pregnancy and is associated with the gestation at spontaneous onset of labor in low-risk nulliparous women and the best cut-off value for prediction of prolonged pregnancy was 3.3cm with a sensitivity of 80% and specificity of 83.1. Conclusions: Transvaginal ultrasound measurement of cervical length at 37 weeks of pregnancy is important for prediction of the duration of pregnancy in primigravidae.

Prediction of labour onset in women who present with symptoms of preterm labour using cervical length

BackgroundDiagnosis of preterm labour is difficult because initial symptoms and signs are often mild and may occur in continuing pregnancies. This study aims to investigate the utility of measuring cervical length, using transvaginal ultrasound, in women presenting to the delivery suite with symptoms of preterm labour.MethodsThis was a prospective cohort study performed in KK Women’s and Children’s Hospital, Singapore from September 2017 to July 2018. Women with singleton pregnancies, presenting with symptoms of contraction pain, between 24+ 0 to 36+ 6 weeks gestation, were included. Transvaginal ultrasound cervical length measurements were done at presentation to the labour ward, after four hours and in the following morning. The primary outcome of the study was delivery within 1 week. All statistical analyses were conducted with Microsoft Excel and Statistical Package for the Social Sciences.ResultsA total of 95 subjects were included. A one-millimeter increase in the 1st cervical length increases scan-to-delivery time by 0.802 days (p-value 0.003, CI 0.280–1.323). Receiver Operator Characteristic (ROC) curve analysis for prediction of delivery within 1 week showed an Area Under Curve (AUC) of 0.667, optimal cut-off value of 27.5mm (sensitivity 77.8 %, specificity 61.6 %). A one-millimetre increase in the 3rd cervical length increases scan-to-delivery time by 0.770 days (p-value 0.023, CI 0.108–1.432). ROC curve analysis for prediction of delivery within 1 week showed an AUC of 0.915, optimal cut-off value of 25.5mm (sensitivity 100 %, specificity 73.6 %). However, the change in cervical length over a period of 1 day was not significant in predicting delivery within 1 week.ConclusionsOur results indicate that by using a cervical length cut off of 27.5mm at presentation, we would have predicted 77.8 % of deliveries within 1 week. If we were to repeat the cervical length scan the next day, with the same cut-off of 27.5mm, we would have predicted 100 % of deliveries within 1 week. In our study, measuring the transvaginal ultrasound cervical length is a reliable diagnostic test for delivery within 1 week. However, the results are limited by the small sample size. Further studies should be conducted with a larger sample size.

Utility of follow-up cervical length screening in low-risk women with a cervical length of 26 to 29 mm

In women with a previous preterm birth, a protocol for serial cervical length screening has been studied and recommended for the identification and treatment of a short cervix. Cervical length screening along with vaginal progesterone has been suggested for low-risk women with singleton pregnancies to treat a short cervix and reduce preterm birth. However, specific protocols for single vs serial ultrasound measuring cervical length in this population are not established. Cost-effectiveness of universal cervical length screening depends on the cost of screening; follow-up of borderline measurements can contribute to increased costs with uncertain benefit. This study aimed to determine the utility of follow-up cervical length screening in otherwise low-risk women with singleton pregnancies with a midtrimester cervical length measurement of 26 to 29 mm through the assessment of the rate of short cervix (≤25 mm) on follow-up ultrasound and subsequent delivery outcomes. This was a 2-year retrospective cohort study at a single urban institution of women with singleton pregnancies with no previous spontaneous preterm birth and an initial transvaginal ultrasound cervical length measurement of 26 to 29 mm identified during universal cervical length screening at time of anatomy ultrasound (18 0/7 to 22 6/7 weeks' gestation). The primary outcome was the rate of short cervix (defined as ≤25 mm on transvaginal ultrasound) on follow-up ultrasound at <24 weeks' gestation. Secondary outcomes included the rate of spontaneous preterm birth (<37 and <34 weeks' gestation). During the study period, there were 2801 women with singleton pregnancies at 18 0/7 to 22 6/7 weeks' gestation with transvaginal ultrasound cervical length screening at time of anatomy scan. Among those women, 201 had a cervical length of 26 of 29 mm, and 184 (7%) had no previous spontaneous preterm birth and were included in the study. Furthermore, 144 women (78%) had a follow-up cervical length completed before 24 weeks' gestation. The mean follow-up interval was 1.5±0.6 weeks. Overall, the percentage of short cervix (≤25 mm) on follow-up was 15% (n=21). Baseline characteristics were similar, but the initial cervical length measurement was shorter in women who subsequently developed a short cervix (26.7±0.8 vs 27.8±1.0; P<.01). Delivery outcomes were available for 126 patients. The rate of spontaneous preterm birth at <37 weeks' gestation in women with an initial cervical length 26 to 29 mm and subsequent short cervix was significantly higher than the rate of spontaneous preterm birth in a historical cohort of low risk women with an initial cervical length >25 mm (16% vs 3%; P=.03). The rate of spontaneous preterm birth at <34 weeks' gestation in women with a subsequent short cervix was 11% (2 of 19). Here, approximately 15% of low-risk women with singleton pregnancies with a midtrimester cervical length measurement of 26 to 29 mm will experience cervical shortening of ≤25 mm before 24 weeks' gestation. Compared to women with singleton pregnancies without a history of preterm birth, the rate of spontaneous preterm birth (16%) in women with an initial cervical length of 26 to 29 mm and a subsequent cervical shortening of ≤25 mm is significantly higher. A total of 111 follow-up ultrasounds measuring cervical length would be required to prevent 1 early preterm birth at <34 weeks' gestation.

333 Prediction of preterm birth by transvaginal-ultrasound and MRI cervical length measurement in pregnancies treated SFLP

Transvaginal ultrasound measurement (TVUS) of cervical length (CL) is one of the most powerful predictors of preterm birth (PTB). Cervical length may also be measured by MRI, but its predictive accuracy for PTB has not been well established. We sought to quantify the predictive accuracy of pre-op TVUS CL and MRI CL as well as post-up TVUS CL measurements for preterm birth outcomes among pregnancies complicated by TTTS that underwent laser surgery Retrospective cohort study to quantify the rate, risk and predictive accuracy of TVUS and MRI for preterm birth <28 and <32 weeks in 626 pregnancies with TTTS that had laser therapy at a single center (2010-2019). Data on pre-operative TVUS (n=579), MRI (n=424), and post-op TVUS (n=596) CL measures were available for analysis. Generalized linear models estimated relative risk and receiver operator characteristic curves generated area under the curve (AUC) to estimate predictive accuracy of CL for PTB outcomes The highest rate and risk of PTB were associated with the shortest CLs measured post-operatively from SFLP in TTTS patients. Over half of pregnancies with perioperative CL ≤2.5cm delivered by 28 weeks of gestation age, regardless of imaging modality. However, TVUS was superior to MRI CL measurement to predict PTB. Pre-op TVUS CL <2.0 cm was the best predictor of PTB <32 wks (AUC 0.8194), and the best predictor of PTB <28 wks was post-op CL <1.5 cm (AUC 0.8148), see Figure. MRI was a poor predictor of PTB at all CL cut-offs Both pre-op and post-op SFLP TVUS measures of CL are good predictors of preterm birth in pregnancies complicated by TTTS, but MRI CL is not. Pre-operative TVUS CL <2cm and post-operative CL <1.5 were the best predictors of PTB <32wks and PTB <28wks, respectively. These data demonstrate that TVUS is the optimal screening modality for cervical length in pregnancies with TTTS undergoing SFLP. This information may assist to counsel patients perioperatively on PTB risk.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

334 Influence of cervical length change after laser surgery for twin-twin transfusion syndrome on pregnancy outcomes

Twin pregnancies complicated by twin-twin transfusion syndrome (TTTS) are at especially high risk of preterm birth. Cases that have selective fetoscopic laser photocoagulation (SFLP) at our institution undergo transvaginal ultrasound (TVUS) measurement of cervical length (CL) before and after SFLP to assess preterm birth risk during the perioperative period Retrospective cohort study comparing pre- and post-op TVUS CL in pregnancies that underwent SFLP at a single center from 4/2010-6/2019. Among 626 SFLP cases, 476 had data on both pre- and post-op CL and comprised the study cohort. Pre-op TVUS CL was obtained <30 days prior to SFLP, and post-op measure was obtained 0 to 5 days after SFLP. Change in cervical length was defined as pre-op CL minus post-op CL. No change in pre- to post-op CL was defined as a change of <0.5 mm Among 476 patients, n=309(64.9%) experienced net decrease in CL, 54(11.3%) had no change and 113(23.7%) had net increase in CL following SFLP. The mean pre-op CL was significantly longer in cases that had net increase in CL after SFLP compared to those that decreased, 4.59cm vs 3.53cm, p=0.0001. There was no difference in mean DVP of the recipient or latency to delivery among groups (mean 10 wks, p=0.606), Table 1. Cases with a net increase in CL after SFLP had lower rates of preterm birth (PTB) <28 and <32 wks. Decrease or no change in CL after SFLP had no significant influence on PTB rates even when accounting for short pre-op CL, Table 2. Short cervix pre-op in combination with CL change was not significantly associated with PTB Increase in cervical length after SFLP is associated with reduced risk of early preterm birth. It has previously been hypothesized that intraoperative amnioreduction of recipient polyhydramnios may decrease PTB by decreasing uterine stretch, however our data did not show differences in mean DVP with respect to CL change. The mechanisms that influence CL changes in the SFLP perioperative period and influence preterm parturition warrant further investigationView Large Image Figure ViewerDownload Hi-res image Download (PPT)

Second-trimester transvaginal ultrasound measurement of cervical length for prediction of preterm birth: a blinded prospective multicentre diagnostic accuracy study.

ObjectiveTo estimate the diagnostic performance of sonographic cervical length for the prediction of preterm birth (PTB).DesignProspective observational multicentre study.SettingSeven Swedish ultrasound centres.SampleA cohort of 11 456 asymptomatic women with a singleton pregnancy.MethodsCervical length was measured with transvaginal ultrasound at 18–20 weeks of gestation (C×1) and at 21–23 weeks of gestation (C×2, optional). Staff and participants were blinded to results.Main outcome measuresArea under receiver operating characteristic curve (AUC), sensitivity, specificity, positive and negative predictive values (PPV and NPV), positive and negative likelihood ratios (LR+ and LR−), number of false‐positive results per true‐positive result (FP/TP), number needed to screen to detect one PTB (NNS) and prevalence of ‘short’ cervix.ResultsSpontaneous PTB (sPTB) at <33 weeks of gestation occurred in 56/11 072 (0.5%) women in the C×1 population (89% white) and in 26/6288 (0.4%) in the C×2 population (92% white). The discriminative ability of shortest endocervical length was better the earlier the sPTB occurred and was better at C×2 than at C×1 (AUC to predict sPTB at <33 weeks of gestation 0.76 versus 0.65, difference in AUC 0.11, 95% CI 0.01–0.23). At C×2, the shortest endocervical length of ≤25 mm (prevalence 4.4%) predicted sPTB at <33 weeks of gestation with sensitivity 38.5% (10/26), specificity 95.8% (5998/6262), PPV 3.6% (10/274), NPV 99.7% (5988/6014), LR+ 9.1, LR− 0.64, FP/TP 26 and NNS 629.ConclusionsSecond‐trimester sonographic cervical length can identify women at high risk of sPTB. In a population of mainly white women with a low prevalence of sPTB its diagnostic performance is at best moderate.Tweetable abstractCervical length screening to predict preterm birth in a white low‐risk population has moderate performance.

Assessment of transvaginal ultrasound measurement of cervical length for prediction of spontaneous onset of labor at term

The objective of this study was to measure the cervical length by transvaginal sonography at term to predict onset and course of spontaneous labor. One hundred and nighty nine pregnant women between 37 to 40 weeks of gestation who fulfilled the inclusion criteria were enrolled in this prospective observational study conducted in department of obstetrics and gynecology of IGGMC, NAGPUR. Out of 199 pregnant women, 154 women had full term vaginal delivery and 45 women underwent emergency cesarean section. The mean cervical length was 2.58cm in women who had vaginal birth and was 3.45cm in women who underwent emergency cesarean section. The best cutoff of transvaginal cervical length was 2.7cm for predicting the spontaneous onset of labor within 7 days, having sensitivity of 90.91% and specificity of 84%.The positive predictive value was 84.9% and negative predictive value of test 90.3%, with diagnostic accuracy of 87.4%. When cervical length is less, then chances of vaginal delivery are significantly higher. Transvaginal cervical length measurement between 37 to 40 weeks is useful test for predicting spontaneous onset of labor within 7 days. It helps women and healthcare providers to plan vaginal birth and also timely decision of referral of those cases requiring immediate care to higher centres for better maternal and foetal outcome.

Ultrasonographic Transabdominal Measurement of Uterine Cervical Length for the Prediction of a Midtrimester Short Cervix.

This study was aimed to estimate the value of transabdominal (TA) ultrasound measurement of cervical length (CL), as an alternative of transvaginal (TV) ultrasound, for universal screening of short cervix in the midtrimester. We conducted a prospective cohort study of nulliparous women with singleton pregnancy at 20 to 24 weeks of gestation. All participants underwent TA ultrasound followed by TV ultrasound with acquisitions of images and videos of the uterine cervix. A second sonographer, blinded to the participants' data and pregnancy outcomes, measured the CL using TA and TV images and videos. Pearson's correlation test and receiver operating characteristic (ROC) curve analyses were performed. A total of 805 participants were recruited, including 780 (97%) where TA CL measurement was feasible. We observed a strong correlation of CL between TA and TV (correlation coefficient: 0.57; p < 0.0001) with a mean TA measurement being 4 mm (95% confidence interval [CI]: -6 to 14 mm) below the mean TV measurement (mean of differences: 5 ± 4 mm). We observed that a TA CL <30 mm was highly predictive of a short cervix defined as a TV CL ≤25 mm (area under the ROC curve: 0.97; 95% CI: 0.95-0.99; p < 0.0001) with a sensitivity of 100% and a false-positive rate of 22%. Universal short cervix screening in nulliparous women could be performed using TA ultrasound, which could allow the avoidance of TV ultrasound in more than three quarter of women. In low-risk population, TV ultrasound could be reserved to women with TA CL <30 mm. · Cervical length (CL) measurement with transabdominal (TA) ultrasound is feasible in most cases and is strongly correlated with CL measured with transvaginal (TV) ultrasound.. · Using a cut-off of 30 mm for TA ultrasound as a first-step screening of short cervix in nulliparous women, three-quarter of TV ultrasound could have been avoided.. · Use of TA CL screening could alleviate some of the logistical challenges of universal TV CL screening..

Second trimester cervical length measurements with transvaginal ultrasound: A prospective observational agreement and reliability study.

Universal screening for preterm delivery by adding transvaginal ultrasound measurement of cervical length to routine second trimester ultrasound has been proposed. The aim is to estimate inter- and intraobserver agreement and reliability of second trimester transvaginal ultrasound measurements of cervical length performed by specially trained midwife sonographers. This is a prospective reliability and agreement study performed in seven Swedish ultrasound centers. In total, 18 midwife sonographers specially trained to perform ultrasound measurements of cervical length and 286 women in the second trimester were included. In each center, two midwife sonographers measured cervical length a few minutes apart in the same woman, the number of women examined per examiner pair varying between 24 and 30 (LIVE study). Sixteen midwife sonographers measured cervical length twice ≥2 months apart on 93 video clips (CLIPS study). The main outcome measures were mean difference, limits of agreement, intraclass correlation coefficient, intra-individual standard deviation, repeatability, Cohen's kappa and Fleiss kappa. The limits of agreement and intraclass correlation coefficient of the best examiner pair in the LIVE study were -4.06 to 4.72 mm and 0.91, and those of the poorest were -11.11 to 11.39 mm and 0.31. In the CLIPS study, median (range) intra-individual standard deviation was 2.14 mm (1.40-3.46), repeatability 5.93 mm (3.88-9.58), intraclass correlation coefficient 0.84 (0.66-0.94). Median (range) interobserver agreement for cervical length ≤25 mm in the CLIPS study was 94.6% (84.9%-98.9%) and Cohen's kappa 0.56 (0.12-0.92), median (range) intraobserver agreement was 95.2% (87.1%-98.9%) and Cohen's kappa 0.68 (0.27-0.93). Agreement and reliability of cervical length measurements differed substantially between examiner pairs and examiners. If cervical length measurements are used to guide management there is potential for both over- and under-treatment. Uniform training and rigorous supervision and quality control are advised.

Preterm Birth Prevention in Appalachian Kentucky: Understanding Barriers and Facilitators Related to Transvaginal Ultrasound Cervical Length Surveillance Among Prenatal Care Providers.

Background: Appalachian Kentucky has higher-than-average rates of preterm birth (PTB)—a health disparity associated with increased maternal and fetal/neonatal morbidity and neonatal mortality. Transvaginal ultrasound (TVU) cervical length measurement is the best predictor of PTB risk, but is underutilized in Appalachia. This study explores prenatal care providers' TVU-related knowledge and practices, and identifies barriers and facilitators, which impact the adoption of this evidence-based technology.Materials and Methods: This study recruited providers from three Appalachian Kentucky health care sites. Prenatal care providers took part in semistructured interviews and completed brief survey scales. Questions focused on PTB knowledge, TVU-related barriers, and suggestions for clinician and/or patient-focused interventions. Transcripts were coded using a multistage process based in grounded theory. Descriptive statistics were calculated.Results: Eleven physicians, one nurse practitioner, one physician assistant, and one midwife completed interviews. Average participant age was 44 years with 17 years in practice; 43% of providers were female. Practitioners described the sociodemographic characteristics, health behaviors (e.g., smoking, opioid abuse), and comorbid conditions (e.g., obesity, hypertension, and diabetes) endemic in Appalachia that heightened their patients' PTB risk. TVU use was reported as important by all respondents, but not all were satisfied with their level of training. The most commonly identified barriers to TVU were patient access to transportation and social support. Participants stressed a need for changing community perceptions regarding consequences of PTB.Conclusions: Providers identified multiple TVU-related barriers and facilitators. These data will inform the design of a multifaceted dissemination and implementation strategy targeting PTB prevention in Appalachia.

Development and validation of a multivariable prediction model of spontaneous preterm delivery and microbial invasion of the amniotic cavity in women with preterm labor

Early spontaneous preterm delivery is often associated with microbial invasion of the amniotic cavity and/or intraamniotic inflammation. The objective of the study was to develop and validate clinically feasible multivariable prediction models of spontaneous delivery within 7 days and microbial invasion of the amniotic cavity in women admitted with diagnose of preterm labor and intact membranes below 34 weeks. We used data from a cohort of women admitted from 2012 to 2018 with diagnosis of preterm labor below 34 weeks who had undergone amniocentesis to rule out microbial invasion of the amniotic cavity. The main outcome was spontaneous delivery within 7 days from admission. The secondary outcome was microbial invasion of the amniotic cavity, defined by a positive culture and/or 16S ribosomal RNA gene in the amniotic fluid. The sample (n= 358) was divided into derivation (2012-2016) and validation cohorts (2017-2018). Logistic regression models using a stepwise selection of variables were developed for the outcomes evaluated. We explored as predictive variables ultrasound cervical length measurement at admission, maternal C-reactive protein, gestational age, amniotic fluid glucose, and interleukin-6 (expressed as log units). Models were developed in the derivation cohort and applied to the validation cohort and diagnostic performance was calculated. The derivation cohort included 263 women and the validation cohort 95 women. One hundred five of the women (39%, 105 of 268) spontaneously delivered in the following 7 days and 68 (19%, 68 of 358) had microbial invasion of the amniotic cavity. For spontaneous delivery within 7 days after admission, 4 predictors were identified: cervical length at admission, gestational age, amniotic fluid glucose, and interleukin-6. The diagnostic performance of the model was assessed in the validation cohort using the receiver operating characteristic curve and showed an area under curve of 0.86 (95% confidence interval, 0.77-0.95) with a detection rate of spontaneous delivery within 7 days of 87%, a false-positive rate of 33%, a negative predictive value of 80%, and a negative likelihood ratio of 0.1908. For microbial invasion of the amniotic cavity, 2 independent predictors of the amniotic cavity were identified: amniotic fluid glucose and maternal C-reactive protein. The receiver operating characteristic curve and an area under curve in the validation cohort was 0.83 (95% confidence interval, 0.70-0.96) with a detection rate of 76%, a false-positive rate of 8%, a negative predictive value of 93%, and a negative likelihood ratio of 0.2591. In women with preterm labor, we propose 2 clinically feasible prediction models to classify as low vs high risk of spontaneous delivery within 7 days and of microbial invasion of the amniotic cavity. The models showed a high diagnostic performance and could be of value to optimize clinical management.