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

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

SUBMITTER: Melamed N

PROVIDER: S-EPMC5045791 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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

Melamed Nir N Pittini Alex A Hiersch Liran L Yogev Yariv Y Korzeniewski Steven S SS Romero Roberto R Barrett Jon J

American journal of obstetrics and gynecology 20160517 4

<h4>Background</h4>Women with a twin gestation are at increased risk for preterm birth (PTB), and sonographic cervical length (CL) is a powerful predictor for spontaneous PTB. Obstetricians frequently monitor CL in multiple gestations; yet, the optimal method to integrate and interpret the results of serial sonographic CL has not been determined.<h4>Objective</h4>We sought to determine whether there are different patterns of cervical shortening in twin gestations, and whether such patterns are r ...[more]

PMID: 27207277

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Project description:BACKGROUND:Cervical length at midtrimester is a powerful predictor of preterm birth in twin gestations. However, given the fact that, in some cases, cervical shortening may become evident only later during the second trimester, it seems reasonable that serial monitoring of cervical length may improve the detection of preterm birth in women with twins. However, data in support of such a practice are limited and conflicting. The contradictory results may be related to the fact that in most of these studies, the analysis of the predictive value of serial measurements of cervical length was limited to data derived from only two sequential measurements of cervical length, while data on the predictive value of multiple (>2) measurements are scarce. OBJECTIVE:We sought to determine whether serial measurements of cervical length can improve the prediction of preterm birth in asymptomatic women with twin gestations compared with a single measurement of cervical length at midgestation. STUDY DESIGN:This was a retrospective cohort study of women with twin pregnancies followed up in a tertiary medical center from 2012 through 2014. All participants underwent routine measurement of cervical length at midgestation and every 2-3 weeks thereafter until 28-32 weeks. For each patient, cervical length was determined at the following time periods: 18+0 to 21+6 weeks (period 1, routine exam), 22+0 to 24+6 weeks (period 2), 25+0 to 27+6 weeks (period 3), and 28+0 to 32+0 weeks (period 4). Measurements of cervical length at periods 2-4 were analyzed in the form of either absolute length (in millimeters) or percent shortening relative to cervical length at period 1. The performance of a stepwise algorithm that incorporated serial measurements of cervical length for the prediction of preterm birth was compared to that achieved with a single measurement of cervical length at period 1. RESULTS:Overall, 441 women with twin pregnancies who were eligible for the study underwent a total of 2374 cervical length measurements. The association of a short cervix (<10th percentile) with preterm birth at <32 weeks persisted in each of the 4 periods of gestation [odds ratio (95% confidence interval): 7.2 (3.1-16.5), 15.3 (6.4-36.7), 10.3 (4.4-24.3), and 23.1(8.3-64.1), respectively]. Compared with a single measurement of cervical length at midgestation (period 1), a stepwise algorithm integrating serial cervical length measurements from all 4 successive gestational age periods resulted in a significant increase in the area under the receiver operating characteristic curve (0.917 vs 0.613, P < .001). Similarly, when a target false-positive rate of 5% was used, the same stepwise algorithm was associated with a higher detection rate (69% vs 28%, P < .001), higher positive likelihood ratio (14.54 vs 5.12), and lower negative likelihood ratio (0.32 vs 0.76) for preterm birth at <32 weeks compared with a single measurement of cervical length at period 1. CONCLUSION:Integration of serial measurements of cervical length using a stepwise algorithm in asymptomatic women with twin gestations can improve the detection of women at risk of preterm birth. Prospective studies are needed to validate these findings, and to investigate whether improved risk assessment performance is sufficient to offset the additional costs associated with serial cervical length measurements.

Project description:ImportanceSpontaneous preterm birth is a major cause of perinatal morbidity and mortality. It is unclear if a cervical pessary can reduce the risk of spontaneous preterm delivery.ObjectiveTo test whether in asymptomatic women with singleton pregnancies and no prior spontaneous preterm birth but with short cervical length on transvaginal ultrasound, use of a cervical pessary would reduce the rate of spontaneous preterm birth at less than 34 weeks of gestation.Design, setting, and participantsParallel-group, nonblinded, randomized clinical trial conducted from March 1, 2016, to May 25, 2017, at a single center in Italy. Asymptomatic women with singleton gestations, no previous spontaneous preterm births, and cervical lengths of 25 mm or less at 18 weeks 0 days to 23 weeks 6 days of gestation were eligible.InterventionsPatients were randomized 1:1 to receive either cervical pessary (n = 150) or no pessary (n = 150). The pessary was removed between 37 weeks 0 days and 37 weeks 6 days of gestation or earlier if clinically indicated. The control group received standard care. For cervical length of 20 mm or shorter, women in both groups were prescribed vaginal progesterone, 200 mg/d, until 36 weeks 6 days of gestation. No bed rest or activity restriction was recommended.Main outcomes and measuresThe primary end point was spontaneous preterm birth at less than 34 weeks of gestation. Secondary outcomes were adverse events.ResultsAmong 300 women who were randomized (mean age, 29 [SD, 6.3] years; mean gestational age, 22 [SD, 1.3] weeks), 100% completed the trial. The primary end point occurred in 11 women (7.3%) in the pessary group and 23 women (15.3%) in the control group (between-group difference, -8.0% [95% CI, -15.7% to -0.4]; relative risk, 0.48 [95% CI, 0.24-0.95]). During follow-up, the pessary group had a higher rate of increased or new vaginal discharge (86.7% vs 46.0%; between-group difference, +40.7% [95% CI, +30.1%-+50.3%]; relative risk, 1.88 [95% CI, 1.57-2.27]).Conclusions and relevanceAmong women without prior spontaneous preterm birth who had asymptomatic singleton pregnancies and short transvaginal cervical length, use of a cervical pessary, compared with no pessary use, resulted in a lower rate of spontaneous preterm birth at less than 34 weeks of gestation. The results of this single-center, nonblinded study among selected pregnant women require confirmation in multicenter clinical trials.Trial registrationclinicaltrials.gov Identifier: NCT02716909.

Project description:ObjectiveTo assess the association between preterm birth and cervical length after arrested preterm labor in high-risk pregnant women.MethodsIn this post-hoc analysis of a randomized clinical trial, transvaginal cervical length was measured in women whose contractions had ceased 48 h after admission for threatened preterm labor. At admission, women were defined as having a high risk of preterm birth based on a cervical length of < 15 mm or a cervical length of 15-30 mm with a positive fetal fibronectin test. Logistic regression analysis was used to investigate the association of cervical length measured at least 48 h after admission and of the change in cervical length between admission and at least 48 h later, with preterm birth before 34 weeks' gestation and delivery within 7 days after admission.ResultsA total of 164 women were included in the analysis. Women whose cervical length increased between admission for threatened preterm labor and 48 h later (32%; n = 53) were found to have a lower risk of preterm birth before 34 weeks compared with women whose cervical length did not change (adjusted odds ratio (aOR), 0.24 (95% CI, 0.09-0.69)). The risk in women with a decrease in cervical length between the two timepoints was not different from that in women with no change in cervical length (aOR, 1.45 (95% CI, 0.62-3.41)). Moreover, greater absolute cervical length after 48 h was associated with a lower risk of preterm birth before 34 weeks (aOR, 0.90 (95% CI, 0.84-0.96)) and delivery within 7 days after admission (aOR, 0.91 (95% CI, 0.82-1.02)). Sensitivity analysis in women randomized to receive no intervention showed comparable results.ConclusionOur study suggests that the risk of preterm birth before 34 weeks is lower in women whose cervical length increases between admission for threatened preterm labor and at least 48 h later when contractions had ceased compared with women in whom cervical length does not change or decreases. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Project description:OBJECTIVE:Preterm birth (birth before 37 weeks of completed gestation) is the leading cause of neonatal death, and has an incidence of 5-13% which is believed to be on the rise. The objective of this study was to determine the rate of spontaneous preterm birth and investigate the relationship between preterm birth and cervical length in a pregnant Asian population. MATERIALS AND METHODS:A prospective observational study between September 2010 and November 2013 was performed at KK Women's and Children's Hospital, Singapore. 1013 women with single viable pregnancies were recruited at less than 14 weeks of gestation between September 2010 and November 2013, excluding those with multiple gestation, pre-existing autoimmune or renal disease or those with current pregnancies complicated by aneuploidy or fetal anomalies. Participant characteristics were obtained from an interviewer-administered questionnaire at the first recruitment visit. Cervical length was measured using ultrasound at each of the 4 antenatal visits (Visit 1: < 14 weeks, Visit 2: 18-22 weeks, Visit 3: 28-32 weeks and Visit 4: > 34 weeks) using the Fetal Medicine Foundation protocol. Data on pregnancy outcomes were obtained from obstetric case notes and records. The main outcome measure examined in this study was that of spontaneous preterm birth and its relationship to cervical length. RESULTS:There was a significantly shorter cervical length both in the 2nd trimester (18 to 22 weeks) and the 3rd trimester (28 to 32 weeks) in the preterm birth group compared to the term birth group (p = 0.028 and p < 0.001 respectively). In the first trimester (11 to 14 weeks), there was no statistically significant difference in cervical length between the two groups (p = 0.425). ROC curve analysis for cervical length in the preterm birth group for 18 to 22 weeks and 28 to 32 weeks showed an AUC of 0.605 and 0.725 respectively. At 28 to 32 weeks of gestation, a cut-off level at 2.49 cm has a sensitivity of 54.8%, specificity of 82.5%, negative predictive value of 97.9% and positive predictive value of 11.1%. CONCLUSION:There is a significantly shorter cervical length in the 2nd and 3rd trimester in the preterm birth group. Cervical length is a moderate predictor of preterm birth with good negative predictive value and a relatively good specificity. Ultrasound cervical length screening for pregnant Asian women between 18 and 22 weeks of gestation with a cutoff of ? 2.48cm can help to identify a group of women who are at risk for preterm birth.

Project description:OBJECTIVE:To assess the value of transvaginal ultrasound parameters after cerclage placement in estimating the risk of spontaneous preterm birth. STUDY DESIGN:This is a retrospective cohort at a single tertiary care center from 2013 to 2016. Women carrying a singleton, nonanomalous fetus with cerclage in situ and at least one postcerclage transvaginal ultrasound from 160/7 to 256/7 weeks' gestation were included. In addition to abstracting maternal demographic and obstetric characteristics, two study investigators separately reviewed each of the images from the first transvaginal ultrasound after cerclage placement, masked to pregnancy outcomes. We measured the angle between the anterior uterine wall and cervical canal at the internal os and external os, closed canal length above and below the stitch, width of the anterior and posterior cervix at the level of the cerclage, and stitch distance from the cervical canal. The presence of additional ultrasound findings such as sludge and cervical funneling was also noted. The main outcomes were preterm birth?<?34 weeks and preterm birth?<?37 weeks. Transvaginal ultrasound parameters were compared between women with preterm birth and those without preterm birth using chi-square, Fisher's exact, and Wilcoxon's rank-sum tests, as appropriate. Log binomial regression was used to estimate the relative risk of preterm birth for all significant obstetric and ultrasound characteristics. RESULTS:A total of 102 women met inclusion criteria: 58% had history-indicated, 20% ultrasound-indicated, and 23% exam-indicated cerclages. Of these, 28 (27.5%) women delivered at?<?34 weeks' gestation, and 48 (47.0%) women delivered at?<?37 weeks' gestation. Preterm birth did not vary by race, maternal age, insurance, smoking, or gestational age of the earliest prior preterm birth (for multiparous women), but women who had preterm birth were more likely to have exam-indicated cerclage. There were several transvaginal ultrasound parameters associated with preterm birth?<?34 weeks and preterm birth?<?37 weeks. Of these, cervical length below the stitch, stitch distance from the cervical canal, straight cervical canal, funneling to or past the stitch, and presence of sludge had the greatest effect sizes. CONCLUSION:Rates of preterm birth are high postcerclage. In addition to measuring cervical length, utilization of postcerclage transvaginal ultrasound to evaluate the location of the cerclage within the cervix, the curvature of the cervical canal, and the presence of funneling and sludge may help identify women who are at the highest risk for preterm birth.

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

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

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