Is there value for serial ultrasonographic assessment of cervical lengths after a cerclage?

Guideline No. 401: Sonographic Cervical Length in Singleton Pregnancies: Techniques and Clinical Applications

OBJECTIVES

• To assess the association between sonography-derived cervical length measurement and preterm birth. • To describe the various techniques to measure cervical length using sonography. • To review the natural history of the short cervix. • To review the clinical uses, predictive ability, and utility of sonography-measured short cervix.

OUTCOMES

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

INTENDED USERS

Clinicians involved in the obstetrical management or cervical imaging of patients at increased risk of a short cervix.

TARGET POPULATION

Women at increased risk of a short cervix or at risk of preterm birth.

EVIDENCE

Literature published up to June 2019 was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, cervical insufficiency, 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 Grey (unpublished) literature was identified through searching the websites of health technology assessment agencies, clinical practice guideline collections, clinical trial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 of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made and graded according to the rankings of the Canadian Task Force on Preventive Health Care (Online Appendix Table A1).

BENEFITS, HARMS, COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the sonographic 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. SUMMARY STATEMENTS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES): RECOMMENDATIONS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES).

McDonald versus Shirodkar cervical cerclage for prevention of preterm birth: a systematic review and meta-analysis of pregnancy outcomes

OBJECTIVE

To compare pregnancy outcomes of patients undergoing either McDonald or Shirodkar cervical cerclage.

METHODS

PubMed, Web of Science, Scopus, and Google scholar were systematically searched up to June 2020. Inter-study heterogeneity was assessed using Cochrane's Q test and the I² statistic. Data were pooled using the fixed- or random-effects model and expressed as relative risk (RR) or weighted mean difference (WMD) as appropriately.

RESULTS

A total of eight observational studies, reporting data on 724 pregnancies, were included in this meta-analysis. As compared to the Shirodkar cerclage, the pooled findings showed that the gestational age at delivery (WMD = -1.95, 95% CI: -2.89 to -1.01, p < .001; I² = 57.5%) and birth weight (WMD = -355.69, 95% CI: -413.76 to -297.62, p < .001; I² = 28.8%) were significantly lower in McDonald cerclage. The risk of preterm premature rupture of the membranes (PPROM) (RR = 1.76; 95% CI: 1.14 - 2.71; I² = 0.0%) and neonatal intensive care unit (NICU) admission (RR = 1.61; 95% CI: 1.09 - 2.39; I² = 62.1%) were also higher for McDonald group. However, no significant difference was observed between both groups in terms of cesarean delivery and perinatal/neonatal death.

CONCLUSION

McDonald cerclage is associated with a shorter duration of pregnancy, lower mean birth weight and increased risk of PPROM and NICU admission compared to the Shirodkar procedure.

The association between sonographic cervical length components and preterm birth in women with ultrasound- or exam-indicated cerclage

OBJECTIVE

To evaluate which parameters of a sonographic cervical length measurement are associated with preterm birth in women with ultrasound- or exam-indicated cerclage.

METHODS

This was a retrospective cohort study of women with singleton pregnancies who underwent ultrasound- or exam-indicated Shirodkar cerclage by a single maternal-fetal medicine practice between 2011 and 2019. All patients underwent sonographic cervical length measurement 2-3 weeks after cerclage placement, and then every 2-4 weeks up to 32 weeks. The images from the first and second post-cerclage cervical lengths were reviewed. Total cervical length, upper cervical length (from the internal cervical os to the cerclage), and lower cervical length (from the cerclage to the external os) were measured. The primary outcome for this study was gestational age at delivery.

RESULTS

A total of 114 women with cerclage were included (85 (74.6%) ultrasound-indicated and 29 (25.4%) exam-indicated). The first and second total cervical lengths correlated with gestational age at delivery (r = 0.26, p=.005; r = 0.33, p<.001, respectively), and the change from first to second was inversely correlated with gestational age at delivery (r = -0.20, p=.032). The first and second upper cervical lengths also correlated with gestational age at delivery (r = 0.22, p = .019; r = 0.33, p<.001, respectively), and the change from first to second upper cervical length was inversely correlated with gestational age at delivery (r= -0.20, r = 0.029). Neither the first nor the second lower cervical lengths were significantly associated with gestational age at delivery. On regression analysis, total cervical length and upper cervical length were not independently associated with gestational age at delivery (p = .108 and p=.806, respectively, for the first scan; p = .153 and p=.166, respectively, for the second scan).

CONCLUSIONS

Postcerclage total cervical length and upper cervical length are both associated with gestational age at delivery and risk of preterm birth, but not independently. After ultrasound- or exam-indicated cerclage, sonographic monitoring of either the total cervical length or the upper cervical length might be predictive of gestational age at delivery and the risk of preterm birth.

The role of three-dimensional ultrasound in pregnancies submitted to cerclage

OBJECTIVE

Cervical cerclage is the standard treatment for cervical incompetence (CI); however, there is still a high risk of preterm birth for women who undergo this treatment. The aim of this study was to longitudinally evaluate findings on two-dimensional transvaginal ultrasonography (2DTVUS) and three-dimensional transvaginal ultrasonography (3DTVUS) that could be related to gestational age at birth.

METHODS

A total of 68 pregnant women who were treated with cerclage were evaluated by 2DTVUS and 3DTVUS in the second and third trimesters of pregnancy. Log-rank tests and Cox regression analyses were used to identify significant findings related to gestational age at delivery.

RESULTS

A cervical length lower than 281 mm (p= 0.0083), a proximal cervical length lower than 10 mm (p= 0.0151), a cervical volume lower than 18.17 cm3 (p= 0.0152), a vascularization index (VI) under 2.153 (p= 0.0044), and a vascularization-flow index (VFI) under 0.961 (p= 0.0059) in the second trimester were all related to earlier delivery. In the third trimester, a cervical length lower than 20.4 mm (p= 0.0009), a VI over 0.54 (p= 0.0327) and a VFI over 2.275 (p= 0.0479) were all related to earlier delivery. Cervical funnelling in the second and third trimesters and proximal cervical length in the third trimester were not related to gestational age at birth. The COX regression analyses showed that cervical volume in the second trimester; FI and VFI in the third trimester were significantly associated with gestational age at birth.

CONCLUSION

In women treated with history-indicated cerclage or ultrasound-indicated cerclage, 2nd trimester cervical volume and 3rd trimester FI and VFI are independent significant sonographic findings associated with time to delivery.

Cervical Cerclage: Does the Location of the Suture Placement Make a Difference?

Introduction: The aim of cervical cerclage is to prevent or treat cervical insufficiency. The goal of the study was to investigate the correlation between the location of the cerclage suture within the cervix and its efficacy in preventing preterm birth. Materials and methods: Sixty-seven images of the cervix performed within two weeks of cerclage placement were extracted from the sonographic database and collected. The location of cerclage was divided into three categories: within the vicinity of the internal os, in the middle portion of the cervix, and in the vicinity of the external os. Gestational age at delivery was analyzed in the groups. Results: In 26 patients, the suture was identified in the vicinity of the internal os. Most of these patients delivered between 34 and 41 weeks of pregnancy. In 29 patients, the suture was located in the middle portion of the cervix. Most of these patients delivered between 33 and 40 weeks of pregnancy. The third group consisted of 12 patients, in whom cervical cerclages were detected in the lower third of the cervix in the vicinity of external os. Five of the 12 patients delivered prior to 30 weeks of pregnancy; the rest delivered between 30 and 34 weeks. Conclusion: Our experience links the sonographically detected cerclage location with pregnancy outcome.

[Does post operative sonographic position of preventive cervical cerclage affect gestational age at birth?]

OBJECTIVE

To evaluate whether the position of preventive cerclage determined by immediate postoperative transvaginal cervical ultrasound is predictive of preterm birth.

METHODS

A single-center retrospective study conducted between 1 August 2007 and 31 December 2015 in a maternity type III who included women carrying out for a single pregnancy and who receive a McDonald preventive cerclage. Measurements of internal os-stitch, stitch-external os and the total length of the cervix were performed during immediate postoperative transvaginal cervical ultrasound. The position of the cerclage has been defined by the internal os-stitch/cervical length and stitch-external os/cervical length ratios. Measures were compared according to gestational age at delivery (before and after 32weeks and before and after 37weeks).

RESULTS

During the study period, 379 single pregnancies that received a McDonald preventive cerclage were included. The mean gestational age at delivery was 37.6±3.6 SA. The rate of preterm birth before 32weeks was 6.5% (n=25) and before 37weeks was 16.6% (n=63). There was no significant difference in the internal ost-stitch/cervical length ratios and the stitch-external ost/cervical length ratio between women who delivered before and after 32weeks or for those who delivered before and after 37weeks. The areas under the ROC curves for the various parameters studied were all less than or equal to 0.6.

CONCLUSIONS

The position of cerclage determined by transvaginal cervical ultrasound in immediate post operative does not seem predictive of the risk of premature birth.

Comparison of two cervical cerclages for the prevention of preterm birth and neonatal complications

OBJECTIVE

To investigate the outcomes of singleton pregnant women with cervical insufficiency undergoing two different cervical cerclages.

METHODS

This is a retrospective cohort study of women who underwent a history- or ultrasound-indicated cerclage (either Shirodkar or McDonald) at a tertiary referral center from 2002 to 2014. Outcome parameters (delivery age, postoperative cervical length, preterm premature rupture of membranes, preterm delivery rate and neonatal complications) were compared between the two cerclage procedures. Multivariate logistic regression analysis was applied to control for significant variables of preterm birth. Kaplan-Meier survival analysis was used to demonstrate delivery age to percentage of term delivery by cerclage type.

RESULTS

Ninety-four cases were initially included. After excluding cases not meeting the study criteria, 60 pregnancies (Shirodkar 36 and McDonald 24) were recruited for analysis. The mean delivery age in the Shirodkar group was more advanced than that in the McDonald group (37.1 ± 3.3 versus 34.8 ± 4.9 weeks, p = 0.039). There were significantly fewer deliveries <37 gestational weeks in the Shirodkar group than in the McDonald group (30.6% versus 58.3%, p = 0.033) but no significant differences in deliveries <28, 32 and 34 gestational weeks. No significant differences were found in neonatal complications except for respiratory distress syndrome (5.6% in Shirodkar versus 29.2% in McDonald, p = 0.023).

CONCLUSION

In the setting of history-indicated or ultrasound-indicated cerclage, Shirodkar was superior to McDonald in the prevention of late preterm birth and neonatal respiratory distress syndrome.

The predictive value of sequential cervical length screening in singleton pregnancies after cerclage: a retrospective cohort study

Background

There are few valid predictors for preterm delivery after cerclage. Experience with a screening program that included four sequential cervical length measurements in singleton pregnancies after cerclage is reviewed.

Methods

In this retrospective cohort study, 88 singleton pregnancies after cerclage were included. Cervical length (CL) measurements were performed perioperatively and at weeks 16 + 0, 18 + 0, 20 + 0, and 22 + 0 by transvaginal ultrasound. Predictive factors for early preterm delivery included patient characteristics, obstetric history and CL measurements and were analyzed separately for women with ultrasound-indicated cerclage and those with history-indicated cerclage. Women with emergency cerclage were excluded.

Results

In women with delivery <35 weeks, CL declined from the 16 + 0 to the 22 + 0 weeks of gestation (p = 0.009). In univariate analysis, all CL measurements were predictive for delivery <35 weeks in women who underwent ultrasound-indicated cerclage and in women who received a history-indicated cerclage, whereas in multivariate analysis only CL three to six days after cerclage remained significant (odds ratio 0.85, 95 % CI 0.73–0.98). In women with ultrasound-indicated cerclage, optimized cut-off was ≤20 mm (specificity 83.8 %, sensitivity 84.2 %).

Conclusions

CL measured three to six days after cerclage placement provides the best information about the risk for delivery <35 weeks.

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.

Reinforcing cerclage for a short cervix at follow-up after the primary cerclage procedure

OBJECTIVE

To determine whether a reinforcing cerclage (RC) for a short cervix measured after the primary cerclage procedure prolonged pregnancy.

METHODS

We conducted a retrospective cohort study of 157 women with singleton gestations who underwent cerclage for standard indications. Women were grouped according to cervical length (CL) at the time of follow-up 1-2 weeks after the initial cerclage placement: ≥25 mm (106 women) and <25 mm with (20 women) or without RC (31 women). Gestational age (GA) at delivery was compared by ANOVA. Survival risk analysis was applied to model GA at delivery adjusted for indication and CL before and after the first cerclage.

RESULTS

Women with CL ≥25mm delivered later than women with CL < 25mm after the first cerclage (p < 0.01). RC did not delay delivery for women with CL < 25 mm (p = 0.17) after the primary procedure. Indication for the primary cerclage (p < 0.01) and CL (p < 0.01) after the primary cerclage were the best predictors for GA at delivery.

CONCLUSION

Placement of RC for short cervix did not prolong duration of pregnancy, GA at delivery or modify the probability of preterm birth.

Does the rate of cervical shortening after cerclage predict preterm birth?

OBJECTIVE

The objective of this study is to evaluate whether the rate of cervical shortening after cerclage can predict spontaneous preterm birth (SPTB).

METHODS

Women who had cervical length (CL) assessments after cerclage placement were identified. The rate of cervical shortening and its relationship with SPTB was established using a generalized linear regression model. Secondary outcomes included relationship between cervical shortening and risk of SPTB in those with a post-cerclage CL <25 mm versus ≥25 mm at 18-20 weeks; and the rate of cervical shortening in women who delivered preterm compared with those who delivered at term.

RESULTS

One hundred thirty-four patients were included and 30 (22.4%) delivered at <36 weeks. A rate of cervical shortening of 1 mm/week conferred a risk of SPTB of 22%. Among women with cerclage who had a CL <25 mm at 18-20 weeks, 1 mm/week of cervical shortening was associated with a 59% risk of SPTB. Patients with cerclage who delivered at term had a slower rate of cervical shortening compared to those who delivered preterm (0.62 mm versus 1.40 mm per week, p = 0.008).

CONCLUSIONS

The rate of cervical shortening after cerclage placement is associated with the risk of SPTB. Sonographic surveillance of the rate of cervical shortening may be useful in assessing risk for SPTB in patients with cerclage.

Factors associated with spontaneous preterm birth risk assessed by transvaginal ultrasound following cervical cerclage

OBJECTIVE

To determine the predictive value of various cervical length measurements postcerclage for the outcome of preterm birth following both elective and rescue cerclage.

MATERIALS AND METHODS

Over a five-year period, we identified 59 women who had a transvaginal cerclage inserted followed by serial cervical length measurement. Of these, 18 were elective cerclages placed at 14 weeks of gestation on the basis of a history of cervical insufficiency and 41 were rescue cerclages performed at gestations ranging from 17 to 23 weeks following a diagnosis of shortened cervix on ultrasound. The women were asymptomatic throughout.

RESULTS

There was a strong correlation between cervical length postcerclage and gestation at delivery. For both groups, preterm birth could be predicted by the total cervical length. In the rescue cerclage group, the change in cervical length was predictive, with positive changes associated with later gestation at delivery. The presence of funnelling was predictive of preterm birth in the elective cerclage group only.

CONCLUSION

Transvaginal cervical length measurement is useful in the prediction of preterm birth postcerclage placement. Serial cervical length measurement postcerclage may assist with timely addition of interventions such, progesterone and antenatal cortico steroids for fetal lung maturation.

[Cervical cerclage]

Cervical cerclage aims to strengthen not only the mechanical properties of the cervix, but also its immunological and anti-infectious functions. The demonstration of a strong interrelation between cervical insufficiency as well as decreased cervical length at endo-vaginal ultrasonography and infection has changed the indications cerclage. Actually we can distinguish three indications for cerclage: prophylactic, for obstetrical history; therapeutic, for shortened cervical length at ultrasonography in patients at risk and; emergency cerclage in case of threatening cervix at physical examination. The McDonald's technique is the most recommended. In case of failure, it is proposed to realize cerclage at a higher level on the cervix either by vaginal or abdominal route.

Association between sonographic cervical appearance and preterm delivery after a history-indicated cerclage

OBJECTIVES

To determine which transvaginal cervical sonographic characteristics are associated with preterm delivery after placement of a history-indicated cerclage.

METHODS

We conducted a case-control study of all women with a singleton gestation and a history-indicated cerclage placed at a single center between January 1, 2008, and October 1, 2012. Cerclages were placed between 12 and 16 weeks' gestation. Cases were defined as women who delivered before 34 weeks' gestation; controls delivered at or after 34 weeks. Transvaginal cervical characteristics, such as cervical funneling, proximal cervical length, distal cervical length, and total cervical length, obtained between 18 and 24 weeks were compared between the two groups. Bivariable, multivariable, and log rank analyses were performed.

RESULTS

A total of 124 women met inclusion criteria, with 17 (14%) delivering before 34 weeks. Cervical funneling, a proximal cervical length of less than 1.5 cm, and a total cervical length of less than 2.5 cm were associated with an increased odds of preterm birth before 34 weeks in the bivariable analysis [odds ratio (OR), 10.9 (95% confidence interval (CI), 2.3-62.8), 2.9 (95% CI, 1.0-8.5), and 4.5 (95% CI, 1.3-16.4), respectively], whereas distal cervical length of less than 1 cm was not significantly associated with delivery before 34 weeks [OR, 3.0 (95% CI, 0.8-11.1)]. In multivariable analysis, only cervical funneling remained associated with preterm delivery before 34 weeks [adjusted OR, 10.6 (95% CI, 2.2-51.5)].

CONCLUSIONS

In women with a history-indicated cerclage, cervical funneling is the only independently significant sonographic finding associated with an increased risk of preterm birth before 34 weeks.

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.

Prematurity prevention: the role of cerclage

PURPOSE OF REVIEW

To summarize the literature on the value of cervical cerclage for the prevention of preterm birth and present the recent advances in its clinical application.

RECENT FINDINGS

The diagnosis of cervical insufficiency is difficult as there are no objective diagnostic criteria. Although widely used, the value of cervical cerclage is still a matter of controversy. The current literature suggests that cerclage placement can prevent preterm delivery in women with a history of at least three second-trimester losses or at least three preterm births and in those with a history of prematurity who have a cervical length of less than 25 mm in the second trimester. It is also possible to improve the perinatal outcome in patients with cervical dilation in the mid-trimester. It is not indicated in multiple pregnancies, however. Further research is needed in methods of excluding inflammation in women with cervical changes on ultrasound prior to cerclage insertion. Transabdominal or laparoscopic cerclage seems to be a promising alternative in women with a history of transvaginal cerclage failure.

SUMMARY

Strict recommendations on the proper use of cerclage cannot be easily made. Data from randomized trials do not support what the current practice in many cases is.