Second-trimester Cervical Length Research Articles

The Association of Second-Trimester Cervical Length With Mode of Delivery [ID 2683533

INTRODUCTION: Second-trimester transvaginal cervical length (TVCL) under 2.5 cm is a well-established risk factor for preterm birth and mid-trimester loss. However, few studies have investigated birth outcomes associated with increasing lengths of “normal” TVCL (2.5 cm or greater). We aimed to evaluate the association of normal TVCL tertiles with mode of delivery. METHODS: This is a retrospective cohort study of patients eligible for vaginal birth with singleton term gestations and normal TVCL (at 16–24 weeks of gestation) delivering at a tertiary care center from June 2022 to June 2023. Mode of delivery was compared by TVCL tertiles: T1, 2.5–3.49 cm; T2, 3.5–4.49 cm; and T3, 4.5 cm or greater. Multivariable logistic regression controlled for potential confounders. Institutional review board approval was obtained. RESULTS: Of 1,033 eligible deliveries, 175 (16.9%), 621 (60.1%), and 237 (22.9%) had TVCL in T1, T2, and T3, respectively. Compared to patients with TVCL in T1, those in T2 and T3 were significantly more likely to have an intrapartum cesarean delivery (CD) (T1 3.4% versus T2 8.5%, P=.02; T3 11.8%, P=.002), with odds ratios (ORs) of 2.63 (CI, 1.1–7.6) and 3.77 (CI, 1.5–11.4), respectively. After adjusting for confounders, those with TVCL in T3 remained statistically more likely to undergo CD than those in T1, adjusted OR 6.7 (CI, 2.3–19.2). Of note, no patients with TVCL in T1 had CD for Stage 1 arrest. CONCLUSION: Patients with longer TVCL at 16–24 weeks are significantly more likely to undergo an intrapartum CD. This association can be considered during patient counseling on delivery outcome expectations.

Cost-effectiveness of universal routine sonographic cervical-length measurement at 19 to 25 weeks’ gestation

National second-trimester scanning of cervical length was introduced in Israel in 2010, and in the decade thereafter, a significant systematic reduction in preterm birth and in the delivery of low birthweight babies was found among singletons. In this study, we sought to estimate the cost-effectiveness of a national policy mandating second-trimester cervical length screening by ultrasound, followed by vaginal progesterone treatment for short cervical length in comparison with no screening strategy. We constructed a decision model comparing 2 strategies, namely (1) universal cervical length screening, and (2) no screening strategy. This study used the national delivery registry of Israel's Ministry of Health. All women diagnosed with a second-trimester cervical length <25 mm were treated with vaginal progesterone and were monitored with a bimonthly ultrasound scan for cervical dynamics and threat of early delivery. Preterm birth prevalence associated with short cervical length, the efficacy of progesterone in preterm birth prevention, and the accuracy of cervical length measurements were derived from previous studies. The cost of progesterone and bimonthly sonographic surveillance, low birthweight delivery, newborn admission to intensive care units, the first-year costs of managing preterm birth and low birthweight, and instances of handicaps and the cost of their follow-up were extracted from the publicly posted registry of Israel's Ministry of Health and Israel Social Securities data. Monte Carlo simulations decision tree mode, Tornado diagrams, and 1- and 2-way sensitivity analyses were implemented and the base case and sensitivity to parameters that were predicted to influence cost-effectiveness were calculated. Without cervical length screening, the discounted quality-adjusted life years were 30.179, and with universal cervical length screening, it increased to 30.198 (difference of 0.018 quality-adjusted life years). The average cost of no screening for cervical length strategy was $1047, and for universal cervical length screening, it was reduced to $998. The calculated incremental cost-effectiveness ratio was -$2676 per quality-adjusted life year (dividing the difference in costs by the difference in quality-adjusted life years). Monte Carlo simulation of cervical length screening of 170,000 singleton newborns (rounded large number close to the number of singleton newborns in Israel) showed that 95.17% of all babies were delivered at gestational week ≥37 in comparison with 94.46% of babies with the no screening strategy. Given 170,000 singleton births, the national savings of screening for short cervical length when compared with no cervical length screening amounted to $8.31M annually, equating to $48.84 for a base case, and the incremental cost-effectiveness ratio for each case of low birthweight or very low birthweight avoided was -$14,718. A cervical length <25 mm was measured for 30,090 women, and of those, 24,650 were false positives. The major parameters that affected the incremental cost-effectiveness ratio were the incidence of preterm birth, the specificity of cervical length measurements, and the efficacy of progesterone treatment. At a preterm birth incidence of <3%, universal screening does not lead to a cost saving. National universal cervical length screening should be incorporated into the routine anomaly scan in the second trimester, because it leads to a drop in the incidence of preterm birth and low birthweight babies in singleton pregnancies, thereby saving costs related to the newborn and gaining quality-adjusted life years.

Establishment and validation of a prognostic model for premature rupture of membranes and preterm delivery in pregnant women after cervical conization.

To investigate the risk factors for premature rupture of membranes (PROM) and preterm birth in pregnant women following cervical conization. A nomogram model was developed and validated to predict the occurrence of PROM and preterm birth in this population. A total of 100 pregnant women who had undergone cervical conization between January 2014 and December 2023 were included. The participants were divided into two groups: 52 in the PROM group and 48 in the non-PROM group. Additionally, 43 cases were in the preterm birth group, and 57 were in the full-term group. Maternal age, body mass index (BMI) during pregnancy, and the conization method were recorded. A nomogram model was constructed to predict PROM and preterm birth, with the predictive performance evaluated using the area under the ROC curve (AUC), C-index, and decision curve analysis (DCA). Univariate and multivariate regression analyses identified pre-pregnancy obesity, advanced maternal age, time after conization, and second-trimester cervical length as significant risk factors for PROM and preterm birth. These factors were incorporated into a clinical nomogram. Calibration curves demonstrated excellent internal and external accuracy for the model. The AUC for the nomogram was 0.8746. DCA showed the clinical utility of the model when the threshold probability ranged from 20% to 60%. Pre-pregnancy obesity, advanced maternal age, time since conization (<12 months), and second-trimester cervical length (<25 mm) were identified as independent risk factors for predicting PROM and preterm birth in pregnant women after cervical conization.

Cost-effectiveness of cervical length screening and progesterone treatment to prevent spontaneous preterm delivery in Sweden.

ABSTRACTObjectiveTo estimate the cost‐effectiveness of strategies to prevent spontaneous preterm delivery (PTD) in asymptomatic singleton pregnancies, using prevalence and healthcare cost data from the Swedish healthcare context.MethodsWe designed a decision analytic model based on the Swedish CERVIX study to estimate the cost‐effectiveness of strategies to prevent spontaneous PTD in asymptomatic women with a singleton pregnancy. The model was constructed as a combined decision‐tree model and Markov model with a time horizon of 100 years. Four preventive strategies, namely ‘Universal screening’, ‘High‐risk‐based screening’ (i.e. screening of high‐risk women only), ‘Low‐risk‐based screening’ (i.e. treatment of high‐risk population and screening of remaining women) and ‘Nullipara screening’ (i.e. treatment of high‐risk population and screening of nulliparous women only), included second‐trimester cervical length (CL) screening by transvaginal ultrasound followed by vaginal progesterone treatment in the case of a short cervix. A fifth preventive strategy involved vaginal progesterone treatment of women with previous spontaneous PTD or late miscarriage but no CL screening (‘No screening, treat high‐risk group’). For comparison, we used a sixth strategy implying no specific intervention to prevent spontaneous PTD, reflecting the current situation in Sweden (‘No screening’). Probabilities for a short cervix (CL ≤ 25 mm; base‐case) and for spontaneous PTD at < 33 + 0 weeks and at 33 + 0 to 36 + 6 weeks were derived from the CERVIX study, and probabilities for stillbirth, neonatal mortality and long‐term morbidity (cerebral palsy) from Swedish health data registers. Costs were based on Swedish data, except costs for cerebral palsy, which were based on Danish data. We assumed that vaginal progesterone reduces spontaneous PTD before 33 weeks by 30% and spontaneous PTD at 33–36 weeks by 10% (based on the literature). All analyses were from a societal perspective. We expressed the effectiveness of each strategy as gained quality‐adjusted life years (QALYs) and presented cost‐effectiveness as average (ACER; average cost per gained QALY compared with ‘No screening’) and incremental (ICER; difference in costs divided by the difference in QALYs for each of two strategies being compared) cost‐effectiveness ratios. We performed deterministic and probabilistic sensitivity analysis. The results of the latter are shown as cost‐effectiveness acceptability curves. Willingness‐to‐pay was set at a maximum of 500 000 Swedish krona (56 000 US dollars (USD)), as suggested by the Swedish National Board of Health and Welfare.ResultsAll interventions had better health outcomes than did ‘No screening’, with fewer screening‐year deaths and more lifetime QALYs. The best strategy in terms of improved health outcomes was ‘Low‐risk‐based screening’, irrespective of whether screening was performed at 18 + 0 to 20 + 6 weeks (Cx1) or at 21 + 0 to 23 + 6 weeks (Cx2). ‘Low‐risk‐based screening’ at Cx1 was cost‐effective, while ‘Low‐risk‐based screening’ at Cx2 entailed high costs compared with other alternatives. The ACERs were 2200 USD for ‘Low‐risk‐based screening’ at Cx1 and 36 800 USD for ‘Low‐risk‐based screening’ at Cx2. Cost‐effectiveness was particularly sensitive to progesterone effectiveness and to productivity loss due to sick leave during pregnancy. The probability that ‘Low‐risk‐based screening’ at Cx1 is cost‐effective compared with ‘No screening’ was 71%.ConclusionInterventions to prevent spontaneous PTD in asymptomatic women with a singleton pregnancy, including CL screening with progesterone treatment of cases with a short cervix, may be cost‐effective in Sweden. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Does late second-trimester cervical length predict unscheduled preterm birth in asymptomatic triplet pregnancies?

Objective Multiple gestation increases the risk of unscheduled preterm birth (PTB), both spontaneous and indicated, leading to increased neonatal morbidity and additional healthcare costs. The purpose of this study was to determine whether cervical length (CL) assessment by 28 weeks could predict unscheduled PTB <34 weeks in triplet pregnancies. Secondary outcomes included prediction of PTB <30 weeks, prediction of PTB based on degree of cervical change and effect of ART-use on PTB. Methods This was a retrospective cohort of women with triplet pregnancies. The exposure variable of interest was short cervix < 25 and <20 millimeters (mm) by 28 weeks. Maternal characteristics were described. The distribution of CLs was analyzed by the primary outcome of unscheduled PTB < 34 weeks, and by PTB <30 weeks (secondary outcome). Gestational age at delivery was compared between women with and without a short cervix. Changes in CL were compared between the groups with unscheduled PTB and those delivering ≥34 and ≥30 weeks. Statistical analyses were performed using appropriate tests. Results Of 92 triplet pregnancies, 51 met the criteria, with 1233 total (411 shortest) CL measurements from 16 to 34 weeks’ gestation. The overall rate of PTB <34 weeks was 31.4% and <30 weeks was 9.8%. The median gestational age at delivery was 32.7 (IQR 2.3) weeks. There were no statistically significant differences in rates of unscheduled PTB in women who had a short cervix and those that did not: PTB <34 weeks with CL <25 mm (p = .53) and CL <20 mm (p = .70); PTB <30 weeks with CL <25 mm (p = .38) and CL <20 mm (p = .26). The degree of cervical change from 18 to 28 weeks was not statistically significant for predicting unscheduled PTB <34 and <30 weeks. Of 70.6% of triplet pregnancies conceived by ARTs, 13.9% had unscheduled PTB <30 weeks, whereas no spontaneously-conceived pregnancies delivered <30 weeks (p = .14). Conclusion Short cervix did not predict unscheduled spontaneous PTB <34 weeks nor <30 weeks in our triplet cohort, nor did the degree of cervical change by 28 weeks predict PTB. Triplets conceived by ARTs may have an increased risk of unscheduled PTB.

Transvaginal sonographic cervical length in first and second trimesters in a low-risk population: a prospective study.

To assess cervical length (CL) longitudinally between the first and second trimesters and to determine the proportion of women with short CL. The study also aimed to assess if women with short CL at 19-24 weeks' gestation could be identified at the time of combined first-trimester screening (cFTS) at 11-14 weeks' gestation, in order to determine the potential value of implementation of CL screening for prediction of preterm delivery in a Danish population. This was a prospective longitudinal study of women with singleton pregnancy attending three University Hospitals in Denmark for combined first-trimester screening from 1 November 2013 to 1 December 2014. Exclusion criteria were multiple pregnancy, uterine anomaly, cerclage or progesterone treatment at inclusion. CL was measured on transvaginal sonography at 11-14 weeks (Cx1), 19-21 weeks (Cx2) and 23-24 weeks (Cx3), by trained operators as a straight line from external to internal os. Women with CL ≤ 25 mm were referred to a maternal-fetal medicine specialist for treatment according to a standardized management protocol. Of the 4904 eligible women, 3477 (71%) participated and had Cx1 recorded. Of those, 3232 (93.0%) had CL measured on all three scans. Median Cx1 was 37 mm, and median Cx2 and Cx3 were 40 mm. The proportion of women with CL ≤ 25 mm increased with gestational age, from 0.41% (95% CI, 0.19-0.62%) at Cx1 to 1.79% (95% CI, 1.34-2.24%) at Cx3. In total, the proportion of women with second-trimester CL (Cx2 or Cx3) ≤ 25 mm was 2.0% (n= 67), of which 38.8% (n= 26) were detected at 19-21 weeks. The probability of short CL between 19 and 24 weeks was greater for those with shorter first-trimester CL. It was nearly nine-fold higher for women with Cx1 ≤ 25 mm compared with Cx1 ≥ 35 mm (17% vs 2%). The performance of Cx1 for prediction of short second-trimester CL was 50% at a 10% false-positive rate. It was found that more than 1500 women would need to be screened for short CL at 19-21 weeks to prevent one case of spontaneous preterm delivery before 34 weeks in a population such as the one in this study. There is an association between first-trimester CL and risk of short cervix in the second trimester. Once short CL was observed, risk of preterm delivery was greatly increased. However, whether universal CL screening should be implemented in this low-risk population depends on cost-benefit analysis taking into account the low proportions of women with short CL and at risk for preterm delivery. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

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

To determine whether a prior uterine evacuation procedure is associated with an increased risk of short cervical length (≤20 mm) in women without prior spontaneous preterm birth. This work was a retrospective cohort study from January 2012 to December 2014 of singletons without prior spontaneous preterm birth with cervical length screening between 18 weeks and 23 weeks 6 days. Women with a prior miscarriage/abortion were excluded if management (medical, surgical, or expectant) was not specified. Prior uterine evacuation was defined as dilation and curettage or dilation and evacuation of a spontaneous or induced abortion. The primary outcome was the risk of short cervical length (≤20 mm) among women with and without 1 of more prior uterine evacuations at any gestational age, assessed by the odds ratio and adjusted odds ratio for confounders. Of 2672 women included, 714 (27%) had at least 1 prior uterine evacuation. The overall incidence of short cervical length in the cohort was 1% (n = 27). Women with at least 1 prior uterine evacuation were more likely to be African American (64% versus 41%; P < .001), smoke (14% versus 8%; P < .001), have a higher body mass index (mean ± SD, 28.1 ± 7.1 versus 26.8 ± 7.1 kg/m2 ; P < .001), and have had prior full-term delivery (60% versus 41%; P < .001). Women with at least 1 prior uterine evacuation had a significantly higher incidence of short cervical length (2% versus 0.7%; P = .003; odds ratio, 2.99 [95% confidence interval, 1.40-6.40]). After adjustment for confounders, prior uterine evacuation remained a source of increased risk of short cervical length (adjusted odds ratio, 2.63 [95% confidence interval, 1.19-5.80]). Although the overall incidence of short cervical length is low (1%-2%), women with at least 1 prior uterine evacuation have at least a 2-fold increased risk of a short second-trimester cervical length compared to women without a prior uterine evacuation.

Second-trimester cervical length and outcomes of induction of labor at term

Objective: To evaluate whether second-trimester cervical length (CL) is associated with induction of labor (IOL) outcomes. Methods: Retrospective cohort study of nulliparous singletons undergoing CL screening at 18 0/7–23 6/7 weeks from 1/1/2012 to 12/31/2013. Women induced at term (≥37 weeks) were included. Primary outcome was vaginal delivery (VD) within 24 h. The effect of CL on outcomes was assessed by incidence across CL quartiles and a receiver operating characteristics (ROC) curve. Odds ratios (OR) were adjusted (aOR) for confounders. Results: Two-hundred-and-sixty-eight women were included. Aside from a difference in incidence of prior cervical surgery between CL quartiles (p <. 02), other characteristics were similar. Ninety-two women (35%) had a VD within 24 h (versus a CD or VD >24 h). A longer a CL was associated with a decreased likelihood of a VD within 24 h with aORs of the third and fourth quartiles of 0.35 (0.16–0.75) and 0.43 (0.21–0.90), respectively, compared to the first quartile. A CL >40 mm was predictive of not having a VD within 24 h with a sensitivity of 56%, specificity of 58% and a positive predictive value of 72%. Conclusion: A second-trimester CL >40 mm is associated with a decreased likelihood of VD within 24 h in an IOL.

Is There an Association between Body Mass Index and Cervical Length? Implications for Obesity and Cervical Length Management in Pregnancy.

Objective Obesity and cervical insufficiency are leading causes of morbidity in pregnancy. We assess the relationship between maternal body mass index (BMI) and second-trimester cervical length. Methods A secondary analysis of a nested case-control study of women with singleton gestations enrolled from 2006 to 2008. The primary exposure was first-trimester BMI, categorized per World Health Organization criteria: normal (18.5 to ≤ 25 kg/m2), overweight (25 to ≤ 30 kg/m2), and obese (> 30 kg/m2). The primary outcome was cervical length > 75th percentile. Results Among 391 pregnant women observed, the median cervical length was 3.6 cm, and the median BMI was 24.8 kg/m2. In multivariable analyses, after adjusting for BMI, age, race, parity, smoking, and gestational age at delivery, women who were overweight (adjusted odds ratio [AOR]: 2.18; 95% CI: 1.20-3.96) and obese (AOR: 2.83; 95% CI: 1.47-5.43) were more than two times more likely to have a cervical length > 75th percentile. When cervical length and BMI were assessed linearly, for each 1.0 kg/m2 increase in BMI, cervical length increased by 0.25 mm. These results were robust to utilizing different cutoffs of cervical length and pre-pregnancy BMI. Conclusion This study demonstrates a relationship between BMI and cervical length suggesting that obesity may be associated with longer cervical length. These results will need to be replicated in larger cohorts undergoing universal cervical length assessment.

CORRELATION BETWEEN PROLONGED PREGNANCY AND SECOND TRIMESTER CERVICAL LENGTH

Journal of Midwifery & Women's HealthVolume 61, Issue 4 p. 517-518 Updates from the Literature CORRELATION BETWEEN PROLONGED PREGNANCY AND SECOND TRIMESTER CERVICAL LENGTH First published: 10 June 2016 https://doi.org/10.1111/jmwh.12496_2Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume61, Issue4July/August 2016Pages 517-518 ACNM Members ACNM Members: Click here to log in RelatedInformation

Preterm birth : can we do better?

Preterm birth (PTB) remains the most serious complication in obstetrics and a substantial excess burden in US healthcare economics. The etiology of PTB is complex and likely has multiple physiological pathways. Unfortunately, current antenatal care screening methods have not been successful in predicting and, eventually, preventing PTB. Although treatments such as progesterone, cerclage and pessary are available for patients with historical risk factors and shortened cervix, these treatments are not universally efficacious. Antenatal care is in great need of new prediction and prevention strategies. The role of more global methods of screening and treatment is still undefined. Most women with clinical risk factors will not deliver early, and aggressive interventions in large segments of the population may not be warranted or cost effective. Furthermore, over half of women who experience PTB have no historical risk factors. Even second-trimester cervical length (CL) has only modest ability to predict which women will experience PTB. There is thus a clear need to identify biomarkers that provide quantitative, individualized assessment of risk early in pregnancy that is specific for each individual woman. The ideal biomarkers would be indicative of the pathway leading to PTB, require no special testing equipment, have a low false positive and negative rate, and offer early identification, allowing adequate time to intervene. We need an aggressive and comprehensive approach to see a dramatic reduction in rates of preterm delivery in the U.S

Second-trimester cervical length as risk indicator for Cesarean delivery in women with twin pregnancy.

To determine whether second-trimester cervical length (CL) in women with a twin pregnancy is associated with the risk of emergency Cesarean section. This was a secondary analysis of two randomized trials conducted in 57 hospitals in The Netherlands. We assessed the univariable association between risk indicators, including second-trimester CL in quartiles, and emergency Cesarean delivery using a logistic regression model. For multivariable analysis, we assessed whether adjustment for other risk indicators altered the associations found in univariable (unadjusted) analysis. Separate analyses were performed for suspected fetal distress and failure to progress in labor as indications for Cesarean section. In total, 311 women with a twin pregnancy attempted vaginal delivery after 34 weeks' gestation. Emergency Cesarean delivery was performed in 111 (36%) women, of which 67 (60%) were performed owing to arrest of labor. There was no relationship between second-trimester CL and Cesarean delivery (adjusted odds ratio (aOR): 0.97 for CL 26(th) -50(th) percentiles; 0.71 for CL 51(st) - 75(th) percentiles; and 0.92 for CL > 75(th) percentile, using CL ≤ 25(th) percentile as reference). In multivariable analysis, the only variables associated with emergency Cesarean delivery were maternal age (aOR, 1.07 (95% CI, 1.00-1.13)), body mass index (BMI) (aOR, 3.99 (95% CI, 1.07-14.9) for BMI 20-23 kg/m(2) ; 5.04 (95% CI, 1.34-19.03) for BMI 24-28 kg/m(2) ; and 3.1 (95% CI, 0.65-14.78) for BMI > 28 kg/m(2) ) and induction of labor (aOR, 1.92 (95% CI, 1.05-3.5)). In nulliparous women with a twin pregnancy, second-trimester CL is not associated with risk of emergency Cesarean delivery.

Association between second-trimester cervical length and cesarean delivery in multiparas.

The purpose of this study was to determine whether there is an association between second-trimester cervical length and cesarean delivery in women with a prior vaginal delivery. We conducted a retrospective cohort study of multiparous women with singleton gestations who underwent routine cervical length screening between 18 and 24 weeks' gestation and labored after 34 weeks. Cervical lengths were divided into quartiles, and the frequency of cesarean delivery was compared across the groups. Indications for cesarean delivery were also compared. A multivariable logistic regression was performed with cervical length as a categorical and a continuous variable to adjust for potential confounders. Of the 2260 multiparas who met inclusion criteria, 63 (2.8%) underwent a cesarean delivery. We observed no association between the second-trimester cervical length quartile and the frequency of cesarean delivery (2.1%, 3.5%, 2.3%, and 3.1%, respectively; P = .434). Further analysis using cervical length as a continuous variable and controlling for potential confounding variables did not change this result (adjusted odds ratio, 1.08; 95% confidence interval, 0.80-1.46). The second-trimester cervical length quartile in multiparas is not associated with an increased frequency of cesarean delivery. This finding differs from studies of nulliparas.

Does Second-Trimester Cervical Length Predict Prolonged Pregnancy?

INTRODUCTION: Third-trimester cervical length has been correlated with delivery timing. Given that second-trimester ultrasonography is routine practice, we sought to evaluate whether second-trimester cervical length is associated with prolonged pregnancy. METHODS: We performed a secondary analysis of data involving women with singleton gestations between 18 0/7 and 23 6/7 weeks of gestation undergoing universal transvaginal ultrasound cervical length screening for preterm birth prediction from January 1, 2012, to December 30, 2012. Women with prior spontaneous preterm births, cerclage in situ, and deliveries at outside institutions were excluded. Women were included if they had spontaneous labor, rupture of membranes, or reached 41 weeks of gestation. The primary outcome was the incidence of prolonged pregnancy (41 0/7 weeks of gestation and beyond). A receiver operating characteristic curve was calculated to identify the threshold cervical length predictive of a prolonged pregnancy. Statistical analysis was performed using SPSS 20.0. RESULTS: Of the 660 women who met inclusion criteria, 108 (16.4%) had prolonged pregnancies. Women with prolonged pregnancies had a higher mean body mass index and were less likely to have had a prior vaginal delivery compared with women without prolonged pregnancies. Women with prolonged pregnancies also had higher mean cervical length (43 compared with 42 mm, P=.057) and a higher incidence of cervical length greater than 30 mm (100% compared with 96%, P=.035; Table 1). The receiver operating characteristic curve demonstrated an area under the curve of 0.542 (standard error 0.027; Figure 1); no optimal cervical length was predictive of a prolonged pregnancy.CONCLUSIONS: Second-trimester cervical length is not predictive of prolonged pregnancy.

Does Second-Trimester Cervical Length Predict the Need for Cesarean Delivery As a Result of Labor Arrest?

Does Second-Trimester Cervical Length Predict the Need for Cesarean Delivery As a Result of Labor Arrest?

Association Between Second-Trimester Cervical Length and Primary Cesarean Delivery

To evaluate whether an increased ultrasonographic cervical length in the second trimester is associated with an increased frequency of cesarean delivery. This is a retrospective cohort study of nulliparous women with a singleton pregnancy who underwent routine cervical length screening between 16 and 24 weeks of gestation and labored after 34 weeks of gestation at a single tertiary care hospital. Women were grouped by cervical length quartile, and the association between cervical length quartile and cesarean delivery was determined in both univariable and multivariable analyses. For every additional centimeter of cervical length, the odds of cesarean delivery increased by 20.3%. Similarly, the frequency of cesarean delivery increased with increasing second-trimester cervical length quartiles (17.4%, 22.3%, 21.8%, 27.7%; P<.001). This association persisted in multivariable analyses that included gestational age at delivery and induction of labor. This increased risk of cesarean delivery was primarily the result of women with arrest disorders in the first stage of labor (P<.001). Increased second-trimester cervical length quartile is associated with an increased frequency of primary cesarean delivery in nulliparous women. : II.

Cervical Length Measurement for the Prediction of Preterm Birth in Multiple Pregnancies: A Systematic Review and Bivariate Meta-Analysis

Transvaginal sonography of the cervix can identify pregnancies at increased risk for preterm birth in both symptomatic and asymptomatic pregnant women. A previous randomized controlled trial has shown that vaginal progesterone is effective in preventing preterm birth in singleton women with asymptomatic cervical shortening during the second trimester. Randomized trials in women with multiple pregnancies have failed to show a significant reduction in preterm birth after treatment with progesterone. Overdistention of the cervix in previous pregnancies may limit the predictive value of cervical length measurement during the second trimester for preterm birth in multiple pregnancies. The aim of this meta-analysis was to review the predictive value of cervical length assessment for preterm birth in asymptomatic women with multiple pregnancies. The investigators conducted electronic searches of MEDLINE and Embase for published articles to 2009 as well as searches of reference lists of relevant articles not found with the electronic search. Two-by-two tables cross-classifying cervical length and gestational age were constructed from articles to score extracted descriptive data and study characteristics. The meta-analysis used a bivariate regression model analysis to construct summary receiver-operating characteristic (ROC) curves estimating sensitivity and specificity for changes in cervical length. A total of 21 studies involving 2757 women were identified Although there was a large variation in the gestational age, cutoff points of cervical length, and the exact definition of preterm birth, summary ROC curve estimates indicated that progressive shortening of cervical length was a good predictor of preterm birth before 34 weeks of gestation. ROC summary estimates showed sensitivity and specificity of 78% and 66%, respectively, at a cervical length of 35 mm, 41% and 87% at 30 mm, 36% and 94% at 25 mm, and 30% and 94% at 20 mm. These findings show that assessment of second-trimester cervical length in women with multiple pregnancies is a strong predictor of preterm birth.

Cervical length measurement for the prediction of preterm birth in multiple pregnancies: a systematic review and bivariate meta‐analysis

To review the literature on cervical length as a predictor of preterm birth in asymptomatic women with a multiple pregnancy. We searched MEDLINE, Embase and reference lists of included articles to identify all studies that reported on the accuracy of cervical length for predicting preterm birth in asymptomatic women with a multiple pregnancy. We scored study characteristics and study quality, and extracted data in order to construct two-by-two tables cross-classifying cervical length and preterm delivery. Meta-analysis using a bivariate model was performed. Summary receiver-operating characteristics (ROC) curves were generated for various test characteristics and outcome definitions. We found 21 studies reporting on 2757 women. There was a large variation in gestational age at measurement, cut-off point for cervical length and definition of preterm birth. The summary ROC curve indicated a good predictive capacity of short cervical length for preterm birth. Summary estimates of sensitivity and specificity for preterm birth before 34 weeks' gestation were 78% and 66%, respectively, for 35 mm, 41% and 87% for 30 mm, 36% and 94% for 25 mm and 30% and 94% for 20 mm. In women with a multiple pregnancy, second-trimester cervical length is a strong predictor of preterm birth. In the absence of effective preventive strategies, there is currently no place in clinical practice for cervical length measurement in this population. However, future studies should evaluate preventive interventions in women with multiple pregnancies and a short cervix, and cervical length should be measured in any trial studying preventive strategies in multiple pregnancies.

Association Between Second-Trimester Cervical Length and Spontaneous Preterm Birth in Twin Pregnancies

The purpose of this study was to define normal second-trimester cervical length (CL) measurements and to estimate the association between second-trimester CL and spontaneous preterm birth (SPTB) in twin pregnancies. A retrospective cohort of 309 asymptomatic patients with twin pregnancies who had routine outpatient CL assessment in the second trimester was studied. We looked at the gestational age periods of 16 to 17 6/7, 18 to 19 6/7, 20 to 21 6/7, and 22 to 23 6/7 weeks. We estimated the association between the CL measurement during each period and SPTB. A short CL was defined both as a CL at or below the 10th percentile for gestational age and 25 mm or less. We also performed regression analyses controlling for a number of clinically important factors: maternal age, chorionicity, in vitro fertilization, multifetal reduction, prior term births, prior preterm births, prepregnancy body mass index, and cerclage. The CL measurement at 16 to 17 6/7 weeks was not associated with gestational age at delivery or SPTB. At 18 to 19 6/7 and 20 to 21 6/7 weeks, the CL measurement was not significantly associated with gestational age at delivery or SPTB before 28 and 32 weeks. There was an association with SPTB before 35 weeks. At 22 to 23 6/7 weeks, the CL measurement had a significant association with gestational age at delivery and SPTB before 28, 32, and 35 weeks (P < .05). A short CL at 22 to 23 6/7 weeks was significantly associated with SPTB before 32 and 35 weeks (P < .05). In second-trimester twin pregnancies, the strongest association between CL and SPTB is at 22 to 23 6/7 weeks.

460: Universal cervical length screening to prevent preterm birth: a cost-effectiveness analysis

Objective To determine whether routine measurement of second-trimester transvaginal cervical length by ultrasound in low-risk singleton pregnancies is a costeffective strategy. Methods We developed a decision analysis model to compare the cost-effectiveness of two strategies for identifying pregnancies at risk for preterm birth: (1) no routine cervical length screening and (2) a single routine transvaginal cervical length measurement at 18–24 weeks’ gestation. In our model, women identified as being at increased risk (cervical length < 1.5 cm) for preterm birth would be offered daily vaginal progesterone supplementation. We assumed that vaginal progesterone reduces preterm birth at < 34 weeks’ gestation by 45%. We also assumed that a decreased cervical length could result in additional costs (ultrasound scans, inpatient admission) without significantly improved neonatal outcomes. The main outcome measure was incremental cost-effectiveness ratio. Results Our model predicts that routine cervical-length screening is a dominant strategy when compared to routine care. For every 100 000 women screened, $12 119 947 can be potentially saved (in 2010 US dollars) and 423.9 quality-adjusted life-years could be gained. Additionally, we estimate that 22 cases of neonatal death or long-term neurologic deficits could be prevented per 100 000 women screened. Screening remained costeffective but was no longer the dominant strategy when cervical-length ultrasound measurement costs exceeded $187 or when vaginal progesterone reduced delivery risk at < 34 weeks by less than 20%.