A randomized controlled trial of cervical scanning vs history to determine cerclage in women at high risk of preterm birth (CIRCLE trial)

Cost-effectiveness of history-indicated cerclage vs cervical length assessment for prevention of preterm birth

BACKGROUND

Preterm birth is one of the major causes of neonatal morbidity and mortality. Preterm delivery is a large burden to our health care system, and a history of preterm birth is one of the most common risk factors for subsequent preterm birth.

OBJECTIVE

We sought to examine the cost-effectiveness of the history-indicated cerclage strategy compared with the transvaginal ultrasound cervical length assessment strategy in individuals with a history of preterm birth.

STUDY DESIGN

We developed a decision analysis model to compare history-indicated cerclage and cervical length assessment. The primary outcome was the net monetary benefit from a maternal and neonatal perspective of both strategies, defined as the value of an intervention with a known willingness to pay threshold for a unit of benefit. The time horizon was set to be a lifetime. Costs (in 2022 USD) included those for the cerclage, serial transvaginal ultrasounds, maternal care for admission, neonatal care, and severe disability. Probabilities, utilities, and costs were derived from the literature. A cost-effectiveness threshold was set at $100,000 per QALY (quality-adjusted life year). We first conducted 1-way sensitivity analyses with associated variables as sensitivity analyses. We then performed a probabilistic sensitivity analysis using Monte Carlo simulation with 1000 trials to test the robustness of the results in the setting of simultaneous changes in probabilities, costs, and utilities.

RESULTS

In our base-case analysis, the history-indicated cerclage strategy compared to transvaginal ultrasound cervical length assessment was associated with more cost ($85,038 vs $70,155), with slightly less effectiveness from the maternal perspective (26.74 QALY vs 26.78 QALY) and from the neonatal perspective (28.91 QALY vs 29.06 QALY), and with less maternal and neonatal net monetary benefit. Therefore, the history-indicated cerclage strategy was dominated. With the 1000 trials of Monte Carlo simulation, transvaginal ultrasound cervical length assessment was the preferred strategy 84% and 88% of the time from the maternal and neonatal perspectives, respectively.

CONCLUSION

The history-indicated cerclage strategy was more expensive and slightly less effective than the transvaginal ultrasound cervical length assessment strategy with a lower net monetary benefit.

The retrospective study for effectiveness of cervical cerclage in preventing recurrent preterm birth

OBJECTIVE

This study aimed to clarify the effectiveness of cervical cerclage in preventing recurrent preterm births.

MATERIALS AND METHODS

A retrospective study was conducted using the perinatal registration database of the Japan Society of Obstetrics and Gynecology for the Perinatal Center from 2014 to 2016. The efficacies of history-indicated, ultrasound-indicated, and physical examination-indicated cerclage as preventive treatments for women with a history of preterm birth were evaluated by comparing cerclage and non-cerclage cases. Fisher's exact test was performed to evaluate any significant differences in patient backgrounds. Prior to the evaluation, propensity score matching was performed for history-indicated and ultrasound-indicated cerclage patients.

RESULTS

For this study, 6060 multiparous women with a history of preterm birth were reviewed. After excluding 17 patients with unknown indications for cervical cerclage, 6043 patients were included in the study. History-indicated and ultrasound-indicated cerclage did not reduce the risk of preterm birth in subsequent pregnancies for any of the pregnancy periods (p = 0.413, p = 1.000). In contrast, physical examination-indicated cerclage significantly reduced the risk of subsequent preterm births for all pregnancy periods (p < 0.001).

CONCLUSION

Subsequent preterm births were effectively prevented only in physical examination-indicated cerclage cases. For history- or ultrasound-indicated cerclage, statistically significant differences in subsequent preterm births were not evident.

Prevention of preterm delivery by cervical cerclage; a comparison of prophylactic and emergency procedures

Objective:

Prophylactic or emergency type cervical cerclage procedures are being used for treatment of cervical insufficiency. The aim was to review and compare the outcomes of these cerclage types and identify factors affecting outcomes.

Material and Methods:

Retrospective review of seventy-five patients in whom transvaginal cervical cerclage procedures were performed over a seven-year period in a tertiary referral center.

Results:

Twenty seven of 75 (36%) patients were in the emergency cerclage group and 48 (64%) of them were in the prophylactic group. Mean body mass index (BMI), hospitalization time and gestational week at cerclage were significantly higher, whereas latency period was significantly shorter for the emergency group. Mean gestational ages at delivery were 35.6±4.5 and 33.6±5.9 weeks in the prophylactic and emergency groups, respectively (p=0.117). Delivery rates under 34^th gestational week were 20.8% and 37.0% in the prophylactic and emergency groups, respectively (p=0.175). Birthweight, and delivery ≥34^th gestational week was higher in the prophylactic group, whereas complication rate was higher in the emergency group, but these differences were not significant. High BMI was associated with more deliveries before 34-week in the prophylactic group. Pre-cerclage cervical length was shorter in patients who delivered before 34 gestational weeks at delivery.

Conclusion:

Prophylactic and emergency cerclage procedures have comparable results regarding gestational week at delivery. High BMI and low pre-cerclage cervical length may have adverse effects on success of cerclage procedures.

Cervical assessment by ultrasound for preventing preterm delivery

BACKGROUND

Measurement of cervical length by ultrasound is predictive of preterm birth (PTB). There are three methods of ultrasound cervical assessment: transvaginal (TVU), transabdominal (TAU), and transperineal (TPU, also called translabial). Cervical length measured by TVU is a relatively new screening test, and has been associated with better prediction of PTB than previously available tests. It is unclear if cervical length measured by ultrasound is effective for preventing PTB. This is an update of a review last published in 2013.

OBJECTIVES

To assess the effectiveness of antenatal management based on transvaginal, transabdominal, and transperineal (also called translabial) ultrasound screening of cervical length for preventing preterm birth.

SEARCH METHODS

For this update, we searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) to 30 August 2018; reviewed the reference lists of all articles, and contacted experts in the field for additional and ongoing trials.

SELECTION CRITERIA

We included published and unpublished randomised controlled trials (RCT) including pregnant women between the gestational ages of 14 to 32 weeks, for whom the cervical length was screened for risk of PTB with TVU, TAU, or TPU. This review focused on studies based on knowledge versus no knowledge of cervical length results, or ultrasound versus no ultrasound for cervical length. We excluded studies based on interventions (e.g. progesterone, cerclage) for short cervical length.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods.

MAIN RESULTS

We included seven RCTs (N = 923): one examined asymptomatic women with twin pregnancies; four included women with singleton pregnancies and symptoms of preterm labour (PTL); one included women with singleton pregnancies and symptoms of preterm premature rupture of membranes (PPROM); and one included asymptomatic singletons. All trials used TVU for screening.We assessed the risk of bias of the included studies as mixed, and the quality of the evidence for primary outcomes as very low for all populations.For asymptomatic women with twin pregnancies, it is uncertain whether knowledge of TVU-measured cervical length compared to no knowledge reduces PTB at less than 34 weeks (risk ratio (RR) 0.62, 95% confidence intervals (CI) 0.30 to 1.25; 1 study, 125 participants) because the quality of the evidence is very low. The results were also inconclusive for preterm birth at 36, 32, or 30 weeks; gestational age at birth, and other maternal and perinatal outcomes.Four trials examined knowledge of TVU-measured cervical length of singletons with symptoms of PTL versus no knowledge. We are uncertain of the effects because of inconclusive results and very low-quality evidence for: preterm births at less than 37 weeks (average RR 0.59, 95% CI 0.26 to 1.32; 2 studies, 242 participants; I² = 66%; Tau² = 0.23). Birth occurred about four days later in the knowledge groups (mean difference (MD) 0.64 weeks, 95% CI 0.03 to 1.25; 3 trials, 290 women). The results were inconclusive for the other outcomes for which there were available data: PTB at less than 34 or 28 weeks; birthweight less than 2500 g; perinatal death; maternal hospitalisation; tocolysis; and steroids for fetal lung maturity.The trial of singletons with PPROM (N = 92) evaluated safety of using TVU to measure cervical length in this population as its primary outcome, not its effect on management. The results were inconclusive for incidence of maternal and neonatal infections between the TVU and no ultrasound groups.In the trial of asymptomatic singletons (N = 296), in which women either received TVU or not, the results were inconclusive for preterm birth at less than 37 weeks (RR 1.27, 95% CI 0.61 to 2.61; I² = 0%), gestational age at birth, and other perinatal and maternal outcomes.We downgraded evidence for limitations in study design, inconsistency between the trials, and imprecision, due to small sample size and wide confidence intervals crossing the line of no effect.No trial compared the effect of knowledge of the CL with no knowledge of CL in other populations, such as asymptomatic women with singleton pregnancies, or symptomatic women with twin pregnancies.

AUTHORS' CONCLUSIONS

There are limited data on the effects of knowing the cervical length, measured by ultrasound, for preventing preterm births, which preclude us from drawing any conclusions for women with asymptomatic twin or singleton pregnancies, singleton pregnancies with PPROM, or other populations and clinical scenarios.Limited evidence suggests that knowledge of transvaginal ultrasound-measured cervical length, used to inform the management of women with singleton pregnancies and symptoms of preterm labour, appears to prolong pregnancy by about four days over women in the no knowledge groups.Future studies could look at specific populations separately (e.g. singleton versus twins; symptoms versus no symptoms of PTL), report on all pertinent maternal and perinatal outcomes, and include cost-effectiveness analyses. Most importantly, future studies should include a clear protocol for management of women based on TVU-measured cervical length.

Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy

BACKGROUND

Cervical cerclage is a well-known surgical procedure carried out during pregnancy. It involves positioning of a suture (stitch) around the neck of the womb (cervix), aiming to give mechanical support to the cervix and thereby reduce risk of preterm birth. The effectiveness and safety of this procedure remains controversial. This is an update of a review last published in 2012.

OBJECTIVES

To assess whether the use of cervical stitch in singleton pregnancy at high risk of pregnancy loss based on woman's history and/or ultrasound finding of 'short cervix' and/or physical exam improves subsequent obstetric care and fetal outcome.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (30 June 2016) and reference lists of identified studies.

SELECTION CRITERIA

We included all randomised trials of cervical suturing in singleton pregnancies. Cervical stitch was carried out when the pregnancy was considered to be of sufficiently high risk due to a woman's history, a finding of short cervix on ultrasound or other indication determined by physical exam. We included any study that compared cerclage with either no treatment or any alternative intervention. We planned to include cluster-randomised studies but not cross-over trials. We excluded quasi-randomised studies. We included studies reported in abstract form only.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion. Two review authors independently assessed risk of bias and extracted data. We resolved discrepancies by discussion. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

This updated review includes a total of 15 trials (3490 women); three trials were added for this update (152 women). Cerclage versus no cerclageOverall, cerclage probably leads to a reduced risk of perinatal death when compared with no cerclage, although the confidence interval (CI) crosses the line of no effect (RR 0.82, 95% CI 0.65 to 1.04; 10 studies, 2927 women; moderate quality evidence). Considering stillbirths and neonatal deaths separately reduced the numbers of events and sample size. Although the relative effect of cerclage is similar, estimates were less reliable with fewer data and assessed as of low quality (stillbirths RR 0.89, 95% CI 0.45 to 1.75; 5 studies, 1803 women; low quality evidence; neonatal deaths before discharge RR 0.85, 95% CI 0.53 to 1.39; 6 studies, 1714 women; low quality evidence). Serious neonatal morbidity was similar with and without cerclage (RR 0.80, 95% CI 0.55 to 1.18; 6 studies, 883 women; low-quality evidence). Pregnant women with and without cerclage were equally likely to have a baby discharged home healthy (RR 1.02, 95% CI 0.97 to 1.06; 4 studies, 657 women; moderate quality evidence).Pregnant women with cerclage were less likely to have preterm births compared to controls before 37, 34 (average RR 0.77, 95% CI 0.66 to 0.89; 9 studies, 2415 women; high quality evidence) and 28 completed weeks of gestation.Five subgroups based on clinical indication provided data for analysis (history-indicated; short cervix based on one-off ultrasound in high risk women; short cervix found by serial scans in high risk women; physical exam-indicated; and short cervix found on scan in low risk or mixed populations). There were too few trials in these clinical subgroups to make meaningful conclusions and no evidence of differential effects. Cerclage versus progesteroneTwo trials (129 women) compared cerclage to prevention with vaginal progesterone in high risk women with short cervix on ultrasound; these trials were too small to detect reliable, clinically important differences for any review outcome. One included trial compared cerclage with intramuscular progesterone (75 women) which lacked power to detect group differences. History indicated cerclage versus ultrasound indicated cerclageEvidence from two trials (344 women) was too limited to establish differences for clinically important outcomes.

AUTHORS' CONCLUSIONS

Cervical cerclage reduces the risk of preterm birth in women at high-risk of preterm birth and probably reduces risk of perinatal deaths. There was no evidence of any differential effect of cerclage based on previous obstetric history or short cervix indications, but data were limited for all clinical groups. The question of whether cerclage is more or less effective than other preventative treatments, particularly vaginal progesterone, remains unanswered.

Role of Cervical Cerclage and Vaginal Progesterone in the Treatment of Cervical Incompetence with/without Preterm Birth History

BACKGROUND

Preterm birth (PTB) is the leading cause of perinatal morbidity and mortality worldwide, and its prevention is an important health-care priority. The cervical incompetence is a well-known risk factor for PTB and its incidence is about 0.1-2.0%, while there is no ideal optimum treatment recommended currently. The cervical incompetence causes about 15% of habitual abortion in 16-28 weeks. This study aimed to evaluate the effectiveness and safety of cervical cerclage and vaginal progesterone in the treatment of cervical incompetence with/without PTB history.

METHODS

We retrospectively observed the pregnancy outcome of 198 patients diagnosed with cervical incompetence from January 2010 to October 2015 in Beijing Hospital. Among the 198 women involved, women who had at least one PTB before 32 weeks (including abortion in the second trimester attributed to the cervical competence) were assigned to the PTB history cohort, and others were assigned to the non-PTB history cohort. All women underwent cerclage placement (cervical cerclage group) or administrated with vaginal progesterone (vaginal progesterone group) until delivery. The outcomes of interest were the differences in gestational age at delivery, the rate of premature delivery, neonatal outcome, complications, and route of delivery between the two treatment groups.

RESULTS

Among the 198 patients with cervical incompetence, 116 patients in PTB history cohort and 80 patients in non-PTB history cohort were included in the final analysis. In the PTB history cohort, cervical cerclage group had significantly longer cervical length at 2 weeks after the start of treatment (23.1 ± 4.6 mm vs. 12.4 ± 9.1 mm, P = 0.002), higher proportion of delivery ≥37 weeks' gestation (63.4% vs. 33.3%, P = 0.008), bigger median birth weight (2860 g vs. 2250 g, P = 0.031), and lower proportion of neonates whose 1-min Apgar score <7 (5.9% vs. 33.3%, P = 0.005), compared with vaginal progesterone group. No significant differences were found in other outcome measures between the two treatment groups. In the non-PTB history cohort, there were no significant differences in the maternal outcomes between cervical cerclage and vaginal progesterone groups, such as median gestational age at delivery (37.4 weeks vs. 37.3 weeks, P = 0.346) and proportion of delivery ≥37 weeks' gestation (55.9% vs. 60.9%, P = 0.569). There were also no significant differences in the neonatal outcomes between the cervical cerclage and vaginal progesterone groups including the median birth weight (2750 g vs. 2810 g, P = 0.145), perinatal mortality (5.9% vs. 6.5%, P = 0.908), and 1-min Apgar scores (8.8% vs. 8.7%, P = 0.984).

CONCLUSIONS

Cervical cerclage showed more benefits in the maternal and neonatal outcomes than vaginal progesterone therapy for women with an asymptomatic short cervix and prior PTB history, while cervical cerclage and vaginal progesterone therapies showed similar effectiveness for women with an asymptomatic short cervix but without a history of PTB.

Early midtrimester serum insulin-like factors and cervical length to predict preterm delivery

OBJECTIVE

To investigate which ultrasound findings or serum biomarkers, including insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 and 3 (IGFBP-1 and IGFBP-3, respectively), in the first and early second trimesters are the best predictors for preterm delivery.

MATERIALS AND METHODS

This was a case-control study conducted between March 2011 and March 2013 with women presenting for routine antenatal care at 11-18 weeks. We collected serum samples from pregnant women and stored them at -80°C. All patients underwent cervical length (CL) measurement at 18-21 weeks. We retrieved frozen samples for analysis from women with subsequent preterm and term delivery. Prediction models were developed using multivariate stepwise logistic regression. Receiver-operating characteristics curves were used to determine the most useful cutoff point.

RESULTS

Of the 72 women recruited, 24 women underwent spontaneous preterm delivery, and 48 women with term delivery were randomly selected as the control group, in a 1:2 ratio. The maternal serum concentration of IGFBP-3 and CL were significantly associated with preterm birth.

CONCLUSION

Among the various known ultrasound findings and serum biomarkers in the early midtrimester, only CL and IGFBP-3 are independent predictors for preterm delivery in asymptomatic women.

Insuffisance cervicale et cerclage cervical

OBJECTIF

La présente directive clinique a pour but de fournir un cadre de référence que les cliniciens pourront utiliser pour identifier les femmes qui sont exposées aux plus grands risques de connaître une insuffisance cervicale, ainsi que pour déterminer les circonstances en présence desquelles la mise en place d'un cerclage pourrait s'avérer souhaitable. RéSULTATS: La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans PubMed ou MEDLINE, CINAHL et The Cochrane Library en 2012 au moyen d'un vocabulaire contrôlé (p. ex. « uterine cervical incompetence ») et de mots clés appropriés (p. ex. « cervical insufficiency », « cerclage », « Shirodkar », « cerclage », « MacDonald », « cerclage », « abdominal », « cervical length », « mid-trimester pregnancy loss »). Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles. Aucune restriction n'a été appliquée en matière de date ou de langue. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu'en janvier 2011. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales.

VALEURS

La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau). RECOMMANDATIONS.

Maternal Whole Blood Gene Expression at 18 and 28 Weeks of Gestation Associated with Spontaneous Preterm Birth in Asymptomatic Women

The heterogeneity of spontaneous preterm birth (SPTB) requires an interdisciplinary approach to determine potential predictive risk factors of early delivery. The aim of this study was to investigate maternal whole blood gene expression profiles associated with spontaneous preterm birth (SPTB, <37 weeks) in asymptomatic pregnant women. The study population was a matched subgroup of women (51 SPTBs, 114 term delivery controls) who participated in the All Our Babies community based cohort in Calgary (n = 1878). Maternal blood at 17–23 (sampling time point 1, T₁) and 27–33 weeks of gestation (T₂) were collected. Total RNA was extracted and microarray was performed on 326 samples (165 women). Univariate analyses determined significant clinical factors and differential gene expression associated with SPTB. Thirteen genes were validated using qRT-PCR. Three multivariate logistic models were constructed to identify gene expression at T₁ (Model A), T₂ (Model B), and gene expression fold change from T₁ to T₂ (Model C) associated with SPTB. All models were adjusted for clinical factors. Model C can predict SPTB with 65% sensitivity and 88% specificity in asymptomatic women after adjusting for history of abortion and anaemia (occurring before T₂). Clinical data enhanced the sensitivity of the Models to predict SPTB. In conclusion, clinical factors and whole blood gene expression are associated with SPTB in asymptomatic women. An effective screening tool for SPTB during pregnancy would enable targeted preventive approaches and personalised antenatal care.

Post-cerclage ultrasonographic cervical length can predict preterm delivery in elective cervical cerclage patients

Objective

To evaluate the usefulness of transvaginal ultrasound measurements of cervical length before and after elective prophylactic cervical cerclage in predicting preterm delivery before 32 weeks of gestation.

Methods

Women who underwent an elective cerclage operation at 14 to 19 weeks of gestation and who delivered between January 2004 and December 2009 were enrolled in this study (n=52). Ultrasonography was performed to measure cervical length before and after cerclage. The primary outcome was defined as preterm delivery before 32 weeks of gestation. A receiver operating characteristic curve was used to determine the most discriminating cut-off values of ultrasonographic cervical parameters predictive of preterm delivery before 32 weeks of gestation.

Results

Among the 52 patients studied, ten delivered before 32 weeks of gestation. Among the ultrasonographic cervical parameters compared, only the cervical length after cerclage was significantly different (shorter) in patients who delivered before 32 weeks of gestation (P=0.037) compared to that of those who delivered after 32 weeks of gestation in univariate and multivariate analyses (odds ratio, 0.402; 95% confidence interval, 0.174 to 0.925; P=0.021). The receiver operating characteristic curve showed that a cervical length of 25 mm or less after cerclage was predictive of preterm delivery before 32 weeks of gestation (area under curve, 0.71; 95% confidence interval, 0.56 to 0.87; P=0.029) with a sensitivity of 91.0% and a specificity of 30.0%.

Conclusion

Patients with a cervical length less than 25 mm after elective cerclage may be at higher risk of preterm delivery before 32 weeks of gestation.

Prediction of spontaneous preterm delivery in singleton pregnancies: where are we and where are we going? A review of literature

Prematurity is the chief cause of neonatal morbidity and mortality. The objective of this study is to review the different methods for predicting preterm delivery in asymptomatic pregnant women and in situations of threatened preterm delivery. A search of the PubMed/Medline database was carried out for the years 1980-2012. We included studies for predicting preterm birth in asymptomatic and symptomatic patients. Models for predicting preterm delivery based on maternal factors, cervical length and obstetric history in first trimester of pregnancy is a valuable avenue of research. Nevertheless, prediction accuracy still needs to be improved. In the second and third trimesters, routine digital vaginal examination is of no value in asymptomatic women. Echography of the cervix is not useful except in patients with a history of late miscarriage or preterm delivery in order to offer them a preventive treatment. In symptomatic women, the combination of digital vaginal examination, cervical echography and fibronectin gives the best predictive results. Electromyography of the uterus and elastography of the cervix are interesting avenues for future research. Identifying patients at risk of preterm delivery should be considered differently at each stage of pregnancy.

[Prevention of obstetrical complications following LEEP, is it possible?]

Recent epidemiological data suggest an increase of the incidence and prevalence of CIN as well as a decrease of the mean age of the patients presenting these lesions. Large loop electrosurgical procedure (LEEP) is the most commonly used treatment method. According to recent studies LEEP provides a 1.4 to 7.0 fold increase of preterm delivery. Cervical cerclage does not show efficiency in reducing this risk, even if cervical shortening is measured by transvaginal ultrasound. Considering histological severity of lesions and the age of patients, number of currently conducted conizations in France could be avoided and so their obstetrical consequences prevented, just because no treatment is necessary or could be done by ablative procedures.

Double versus single cervical cerclage for patients with recurrent pregnancy loss: a randomized clinical trial

AIM

To compare the effectiveness of the double cervical cerclage method versus the single method in women with recurrent second-trimester delivery.

METHOD

In this randomized clinical trial, we included 33 singleton pregnancies suffering from recurrent second-trimester pregnancy loss (≥2 consecutive fetal loss during second-trimester or with a history of unsuccessful procedures utilizing the McDonald method), due to cervical incompetence. Patients were randomly assigned to undergo either the classic McDonald method (n = 14) or the double cerclage method (n = 19). The successful pregnancy rate and gestational age at delivery was also compared between the two groups.

RESULTS

The two study groups were comparable regarding their baseline characteristics. The successful pregnancy rate did not differ significantly between those who underwent the double cerclage method or the classic McDonald cerclage method (100% vs 85.7%; P = 0.172). In the same way, the preterm delivery rate (<34 weeks of gestation) was comparable between the two study groups (10.5% vs 35.7%; P = 0.106). Those undergoing the double cerclage method had longer gestational duration (37.2 ± 2.6 vs 34.3 ± 3.8 weeks; P = 0.016).

CONCLUSION

The double cervical cerclage method seems to provide better cervical support, as compared with the classic McDonald cerclage method, in those suffering from recurrent pregnancy loss, due to cervical incompetence.

What is predictive of preterm delivery in the first trimester: isthmus or cervical length?

OBJECTIVE

This study aims to evaluate the utility of first trimester cervical ultrasonography in predicting preterm delivery by separate analysis of measurements of cervical and isthmus length.

METHODS

This is a cohort study based on data collected prospectively on singletons between 1 July 2011 and 1 February 2013. Mean cervical, isthmus and cervico-isthmic complex length were measured for deliveries before and after 37 weeks.

RESULTS

A total of 1494 pregnancies were analysed, including 51 cases of spontaneous preterm delivery (3.4%). The cervico-isthmic complex in the first trimester was significantly shorter in patients who delivered before term (43.8 mm vs 47.5 mm, p = 0.04). This difference is related to differences in length at the isthmus (10.7 mm vs 14.1 mm, p = 0.005) rather than at the cervix proper (34.5 mm vs 35.0 mm, p = 0.56).

CONCLUSIONS

Measurement of the cervico-isthmic complex enables detection of a number of patients who will go on to deliver before term. Further studies are necessary to confirm that isthmic length and not cervical length is predictive of preterm delivery.

Adjunctive therapies to cerclage for the prevention of preterm birth: a systematic review

The aim of this paper is to provide a thorough summary of published studies that have assessed the efficacy of adjunctive therapies used in addition to cervical cerclage as a preventive measure for preterm birth. We limited our paper to patients treated with cerclage plus an additional prophylactic therapy compared to a reference group of women with cerclage alone. The specific adjunctive therapies included in this systematic review are progesterone, reinforcing or second cerclage placement, tocolytics, antibiotics, bedrest, and pessary. We searched PubMed and Cochrane databases without date criteria with restriction to English language and human studies and performed additional bibliographic review of selected articles and identified 305 total studies for review. Of those, only 12 studies compared the use of an adjunctive therapy with cerclage to a reference group of cerclage alone. None of the 12 were prospective randomized clinical trials. No comparative studies were identified addressing the issues of antibiotics, bedrest, or pessary as adjunctive treatments to cerclage. None of the 12 studies included in this paper demonstrated a clear benefit of any adjunctive therapy used in addition to cerclage over and above cerclage used alone; however, few studies with small numbers limited the strength of the conclusions.

Cervical assessment by ultrasound for preventing preterm delivery

BACKGROUND

Measurement of cervical length (CL) by transvaginal ultrasound (TVU) is predictive of preterm birth (PTB). It is unclear if this screening test is effective for prevention of PTB.

OBJECTIVES

To assess the effectiveness of antenatal management based on transvaginal ultrasound of cervical length (TVU CL) screening for preventing PTB.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2012), reviewed the reference lists of all articles and contacted experts in the field for additional and ongoing trials.

SELECTION CRITERIA

Published and unpublished randomized controlled trials including pregnant women between the gestational ages of 14 to 32 weeks screened with TVU CL for risk of PTB. This review focuses exclusively on studies based on knowledge versus no knowledge of TVU CL results.

DATA COLLECTION AND ANALYSIS

All potential studies identified from the search were independently assessed for inclusion by three review authors. We also analyzed studies for quality measures and extracted data.

MAIN RESULTS

Of the 13 trials identified, five were eligible for inclusion (n = 507). Three included singleton gestations with preterm labor (PTL); one included singleton gestations with preterm premature rupture of membranes (PPROM); and one included twin gestations with or without PTL.In the three trials of singleton gestations with PTL, 290 women were randomized; 147 to knowledge and 143 to no knowledge of TVU CL. Knowledge of TVU CL results was associated with a non-significant decrease in PTB at less than 37 weeks (22.3% versus 34.7%, respectively; average risk ratio 0.59, 95% confidence interval (CI) 0.26 to 1.32; two trials, 242 women) and at less than 34 weeks (6.9% verus 12.6%; RR 0.55, 95% CI 0.25 to 1.20; three trials, 256 women). Delivery occurred at a later gestational age in the knowledge versus no knowledge groups (mean difference (MD) 0.64 weeks, 95% CI 0.03 to 1.25; three trials, 290 women). For all other outcomes for which there were available data (PTB at less than 34 or 28 weeks; birthweight less than 2500 grams; perinatal death; maternal hospitalization; tocolysis; and steroids for fetal lung maturity), there was no evidence of a difference between groups.The trial of singleton gestations with PPROM (n = 92) evaluated as its primary outcome safety of TVU CL in this population, and not its effect on management. There was no evidence of a difference in incidence of maternal and neonatal infections between the TVU CL and no TVU CL groups.In the trial of twin gestations with or without PTL (n = 125), there was no evidence of a difference in PTB at less than 36, 34, or 30 weeks, gestational age at delivery, and other perinatal and maternal outcomes between the TVU CL and the no TVU CL groups. Life-table analysis revealed significantly less PTB at less than 35 weeks in the TVU CL group compared with the no TVU CL group (P = 0.02).

AUTHORS' CONCLUSIONS

Currently, there is insufficient evidence to recommend routine screening of asymptomatic or symptomatic pregnant women with TVU CL. Since there is a non-significant association between knowledge of TVU CL results and a lower incidence of PTB at less than 37 weeks in symptomatic women, we encourage further research. Future studies should look at specific populations separately (e.g., singleton versus twins; symptoms of PTL or no such symptoms), report on all pertinent maternal and perinatal outcomes, and include cost-effectiveness analyses. Most importantly, future studies should include a clear protocol for management of women based on TVU CL results, so that it can be easily evaluated and replicated.

Vaginal progesterone vs. cervical cerclage for the prevention of preterm birth in women with a sonographic short cervix, previous preterm birth, and singleton gestation: a systematic review and indirect comparison metaanalysis

OBJECTIVE

No randomized controlled trial has compared vaginal progesterone and cervical cerclage directly for the prevention of preterm birth in women with a sonographic short cervix in the mid trimester, singleton gestation, and previous spontaneous preterm birth. We performed an indirect comparison of vaginal progesterone vs cerclage using placebo/no cerclage as the common comparator.

STUDY DESIGN

Adjusted indirect metaanalysis of randomized controlled trials.

RESULTS

Four studies that evaluated vaginal progesterone vs placebo (158 patients) and 5 studies that evaluated cerclage vs no cerclage (504 patients) were included. Both interventions were associated with a statistically significant reduction in the risk of preterm birth at <32 weeks of gestation and composite perinatal morbidity and mortality compared with placebo/no cerclage. Adjusted indirect metaanalyses did not show statistically significant differences between vaginal progesterone and cerclage in the reduction of preterm birth or adverse perinatal outcomes.

CONCLUSION

Based on state-of-the-art methods for indirect comparisons, either vaginal progesterone or cerclage are equally efficacious in the prevention of preterm birth in women with a sonographic short cervix in the mid trimester, singleton gestation, and previous preterm birth. Selection of the optimal treatment needs to consider adverse events, cost and patient/clinician preferences.

Limited relationship between cervico-vaginal fluid cytokine profiles and cervical shortening in women at high risk of spontaneous preterm birth

Objective

To determine the relationship between high vaginal pro-inflammatory cytokines and cervical shortening in women at high risk of spontaneous preterm labor and to assess the influence of cervical cerclage and vaginal progesterone on this relationship.

Methods

This prospective longitudinal observational study assessed 112 women with at least one previous preterm delivery between 16 and 34 weeks’ gestation. Transvaginal cervical length was measured and cervico-vaginal fluid sampled every two weeks until 28 weeks. If the cervix shortened (<25 mm) before 24 weeks’ gestation, women (cases) were randomly assigned to cerclage or progesterone and sampled weekly. Cytokine concentrations were measured in a subset of cervico-vaginal fluid samples (n = 477 from 78 women) by 11-plex fluid-phase immunoassay.

Results

All 11 inflammatory cytokines investigated were detected in cervico-vaginal fluid from women at high risk of preterm birth, irrespective of later cervical shortening. At less than 24 weeks’ gestation and prior to intervention, women destined to develop a short cervix (n = 36) exhibited higher cervico-vaginal concentrations than controls (n = 42) of granulocyte-macrophage colony-stimulating factor [(GM-CSF) 16.2 fold increase, confidence interval (CI) 1.8–147; p = 0.01] and monocyte chemotactic protein-1 [(MCP-1) 4.8, CI 1.0–23.0; p = 0.05]. Other cytokines were similar between cases and controls. Progesterone treatment did not suppress cytokine concentrations. Interleukin (IL)-6, IL-8, granulocyte colony-stimulating factor (G-CSF), interferon (IFN)-γ and tumour necrosis factor (TNF)-α concentrations were higher following randomization to cerclage versus progesterone (p<0.05). Cerclage, but not progesterone treatment, was followed by a significant increase in cervical length [mean 11.4 mm, CI 5.0–17.7; p<0.001].

Conclusions

Although GM-CSF and MCP-1 cervico-vaginal fluid concentrations were raised, the majority of cervico-vaginal cytokines did not increase in association with cervical shortening. Progesterone treatment showed no significant anti-inflammation action on cytokine concentrations. Cerclage insertion was associated with an increase in the majority of inflammatory markers and cervical length.

Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy

BACKGROUND

Cervical cerclage is a well-known surgical procedure carried out during pregnancy. It involves positioning of a suture (stitch) around the neck of the womb (cervix), aiming to give a mechanical support to the cervix and thereby reducing the risk of preterm birth. The effectiveness and safety of this procedure remains controversial.

OBJECTIVES

To assess whether the use of cervical stitch in singleton pregnancy at high risk of pregnancy loss based on a woman's history and/or ultrasound finding of 'short cervix' and/or physical exam improves subsequent obstetric care and fetal outcome.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2011) and reference lists of identified studies.

SELECTION CRITERIA

We included all randomised trials of cervical suturing in singleton pregnancies carried out when pregnancy was considered to be at sufficiently high risk of pregnancy loss for cerclage to be potentially indicated. We included any study that compared cerclage with either no treatment or any alternative intervention.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion. Two review authors independently assessed risk of bias and extracted data. Data were checked for accuracy.

MAIN RESULTS

We included 12 trials (involving 3328 women). When cerclage was compared with no treatment, there was no statistically significant difference in perinatal deaths (8.4% versus 10.7%) (risk ratio (RR) 0.78; 95% confidence interval (CI) 0.61 to 1.00; eight trials, 2391 women) and neonatal morbidity (9.6% versus 10.2%) (RR 0.95; 95% CI 0.63 to 1.43; four trials, 818 women), despite significant reduction in preterm births (average RR 0.80; 95% CI 0.69 to 0.95; nine trials, 2898 women). Cervical cerclage was associated with the higher rate of maternal side effects (vaginal discharge and bleeding, pyrexia) (average RR 2.25; 95% CI 0.89 to 5.69; three trials, 953 women). Caesarean section rates were significantly higher after cervical cerclage (RR 1.19; 95% CI 1.01 to 1.40; 8 trials, 2817 women).There was no evidence of any important differences across all prespecified clinical subgroups (history-indicated, ultrasound-indicated)One study that compared cerclage with weekly intramuscular injections of 17 α-hydroxyprogesterone caproate in women with a short cervix detected by transvaginal ultrasound, failed to reveal any obvious differences in obstetric and neonatal outcomes between the two management strategies.Two studies compared the benefits of performing cerclage based on previous history with cerclage, only if the cervix was found to be short on transvaginal ultrasound. There was no significant difference in any of the primary and secondary outcomes.

AUTHORS' CONCLUSIONS

Compared with no treatment, cervical cerclage reduces the incidence of preterm birth in women at risk of recurrent preterm birth without statistically significant reduction in perinatal mortality or neonatal morbidity and uncertain long-term impact on the baby. Ceasarean section is more likely in women who had cervical suture inserted during pregnancy.The decision on how best to minimise the risk of recurrent preterm birth in women at risk, either because of poor history of a short or dilated cervix, should be 'personalised', based on the clinical circumstances, the skill and expertise of the clinical team and, most importantly, woman's informed choice.

SOGC Clinical Practice Guideline. Ultrasonographic cervical length assessment in predicting preterm birth in singleton pregnancies

OBJECTIVES

To review (1) the use of ultrasonographic-derived cervical length measurement in predicting preterm birth and (2) interventions associated with a short cervical length.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

EVIDENCE

Published literature was retrieved through searches of PubMed and The Cochrane Library up to December 2009, using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, incompetent cervix, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee and the Maternal Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made according to the guidelines developed by The Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the ultrasonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth.

SPONSORS

The Society of Obstetricians and Gynaecologists of Canada.

Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial

OBJECTIVES

Women with a sonographic short cervix in the mid-trimester are at increased risk for preterm delivery. This study was undertaken to determine the efficacy and safety of using micronized vaginal progesterone gel to reduce the risk of preterm birth and associated neonatal complications in women with a sonographic short cervix.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled asymptomatic women with a singleton pregnancy and a sonographic short cervix (10-20 mm) at 19 + 0 to 23 + 6 weeks of gestation. Women were allocated randomly to receive vaginal progesterone gel or placebo daily starting from 20 to 23 + 6 weeks until 36 + 6 weeks, rupture of membranes or delivery, whichever occurred first. Randomization sequence was stratified by center and history of a previous preterm birth. The primary endpoint was preterm birth before 33 weeks of gestation. Analysis was by intention to treat.

RESULTS

Of 465 women randomized, seven were lost to follow-up and 458 (vaginal progesterone gel, n=235; placebo, n=223) were included in the analysis. Women allocated to receive vaginal progesterone had a lower rate of preterm birth before 33 weeks than did those allocated to placebo (8.9% (n=21) vs 16.1% (n=36); relative risk (RR), 0.55; 95% CI, 0.33-0.92; P=0.02). The effect remained significant after adjustment for covariables (adjusted RR, 0.52; 95% CI, 0.31-0.91; P=0.02). Vaginal progesterone was also associated with a significant reduction in the rate of preterm birth before 28 weeks (5.1% vs 10.3%; RR, 0.50; 95% CI, 0.25-0.97; P=0.04) and 35 weeks (14.5% vs 23.3%; RR, 0.62; 95% CI, 0.42-0.92; P=0.02), respiratory distress syndrome (3.0% vs 7.6%; RR, 0.39; 95% CI, 0.17-0.92; P=0.03), any neonatal morbidity or mortality event (7.7% vs 13.5%; RR, 0.57; 95% CI, 0.33-0.99; P=0.04) and birth weight < 1500 g (6.4% (15/234) vs 13.6% (30/220); RR, 0.47; 95% CI, 0.26-0.85; P=0.01). There were no differences in the incidence of treatment-related adverse events between the groups.

CONCLUSIONS

The administration of vaginal progesterone gel to women with a sonographic short cervix in the mid-trimester is associated with a 45% reduction in the rate of preterm birth before 33 weeks of gestation and with improved neonatal outcome.

The role of prophylactic cerclage in preventing preterm delivery after electrosurgical conization

OBJECTIVE

To evaluate pregnancy outcomes after electrosurgical conization.

METHODS

We retrospectively analyzed the outcomes of 56 singleton pregnancies after electrosurgical conization of the uterine cervix. Of the 56 cases, 25 women underwent prophylactic cerclage with McDonald procedure (cerclage group), and 31 were managed expectantly (expectant group). Pregnancy outcomes including rate of preterm delivery were compared, and the effect of potential risk factors such as depth of cone, interval between conization and pregnancy, and cervical length on the risk of preterm delivery was assessed.

RESULTS

The rate of preterm delivery was significantly higher in women with a history of electrosurgical conization than those without (32.1% vs. 15.2%, p<0.001). However, preterm delivery rate was not different between the two groups (expectant group vs. cerclage group; <28 week, 6.5% vs. 8.0%, p=1.000; <34 week, 19.4% vs. 20.0%, p=1.000; <37 week, 29.0% vs. 36.0%, p=0.579). All obstetric and neonatal outcomes were similar in the two groups. Even when we confined the study subjects to 19 women (19/56, 33.9%) with cervical length less than 25 mm, the preterm delivery rate also was not significantly different between the expectant (n=7) and cerclage group (n=12). Finally, the potential risk factors for preterm delivery were not associated with risk of preterm delivery in patients with a history of electrosurgical conization.

CONCLUSION

The rate of preterm delivery was significantly higher in women with a history of electrosurgical conization before pregnancy. However, prophylactic cervical cerclage did not prevent preterm delivery in these patients.

Care for women with prior preterm birth

Women who have delivered an infant between 16 and 36 weeks' gestation have an increased risk of preterm birth in subsequent pregnancies. The risk increases with more than 1 preterm birth and is inversely proportional to the gestational age of the previous preterm birth. African American women have rates of recurrent preterm birth that are nearly twice that of women of other backgrounds. An approximate risk of recurrent preterm birth can be estimated by a comprehensive reproductive history, with emphasis on maternal race, the number and gestational age of prior births, and the sequence of events preceding the index preterm birth. Interventions including smoking cessation, eradication of asymptomatic bacteriuria, progestational agents, and cervical cerclage can reduce the risk of recurrent preterm birth when employed appropriately.

Cervical assessment by ultrasound for preventing preterm delivery

BACKGROUND

Measurement of cervical length (CL) by transvaginal ultrasound (TVU) is predictive of preterm birth (PTB). It is unclear if this screening test is effective for prevention of PTB.

OBJECTIVES

To assess the effectiveness of antenatal management based on TVU CL screening for preventing PTB.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2008), MEDLINE (1966 to September 2008), and reviewed the reference list of all articles.

SELECTION CRITERIA

Published and unpublished randomized controlled trials including pregnant women between the gestational ages of 14 to 32 weeks screened with TVU CL for risk of PTB. This review focuses exclusively on studies based on knowledge versus no knowledge of TVU CL results.

DATA COLLECTION AND ANALYSIS

All potential studies identified as in the search were assessed for inclusion by three independent review authors. We also analyzed studies for quality measures and extracted data.

MAIN RESULTS

Of 12 trials identified, five were eligible for inclusion (n = 507). Three included singleton gestations with preterm labor (PTL); one included singleton gestations with preterm prelabour rupture of membranes (PPROM); and one included twin gestations without or with PTL.In the three trials of singleton gestations with PTL, 290 women were randomized; 147 to knowledge and 143 to no knowledge of TVU CL. Knowledge of TVU CL results was associated with a non-significant decrease in PTB at less than 37 weeks (22.3% versus 34.7%, respectively; risk ratio 0.59, 95% confidence interval (CI) 0.26 to 1.32). Delivery occurred at a later gestational age in the knowledge versus no knowlege groups (mean difference 0.64 weeks (CI 0.03 to 1.25)). All other outcomes for which there were available data (PTB at less than 34 or 28 weeks; birthweight less than 2500 grams; perinatal death; maternal hospitalization; tocolysis; and steroids for fetal lung maturity) were similar in the two groups.The trial of singleton gestations with PPROM (n = 92) evaluated as its primary outcome safety of TVU CL in this population, and not its effect on management. The incidence of maternal and neonatal infections was similar in the TVU CL and no TVU CL groups.In the trial of twin gestations with or without PTL (n = 125), PTB at less than 36, 34, or 30 weeks, gestational age at delivery, and other perinatal and maternal outcomes were similar in the TVU CL and the no TVU CL groups. Life table analysis revealed significantly less preterm birth at less than 35 weeks in the TVU CL group compared to the no TVU CL group (P = 0.02).

AUTHORS' CONCLUSIONS

Currently there is insufficient evidence to recommend routine screening of asymptomatic or symptomatic pregnant women with TVU CL. Since there is a non-significant association between knowledge of TVU CL results and a lower incidence of PTB at less than 37 weeks in symptomatic women, we encourage further research. Future studies should look at specific populations separately (eg singleton versus twins; symptoms of PTL or no such symptoms), report on all pertinent maternal and perinatal outcomes, and include cost-effectiveness analyses. Most importantly, future studies should include a clear protocol for management of women based on TVU CL results, so that it can be easily evaluated and replicated.