Early transvaginal ultrasonography versus early cerclage in women with an unclear history of incompetent cervix

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 Grey (unpublished) literature was identified through searching the websites of health technology assessment agencies, clinical practice guideline collections, clinical trial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).

Recurrent second trimester pregnancy loss: evaluation and management

PURPOSE OF REVIEW

Recurrent pregnancy loss usually refers to first trimester losses. The present article describes the importance of a thorough evaluation for any patient presenting with a second trimester loss, and reviews current data regarding evidence-based evaluation and management for those families who have had recurrent episodes of second trimester losses. A management protocol is presented to guide management of a current pregnancy with a history of recurrent second trimester losses.

RECENT FINDINGS

Previous literature has focused on isolated causes of second trimester loss and management. The present review incorporates all presentations of loss into a stepwise evaluative and management paradigm.

SUMMARY

This comprehensive literature review and management protocol will provide the clinician with a thorough, systematic, and practical approach to the patient with recurrent pregnancy loss in order to maximize her chance of optimal pregnancy outcome.

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

OBJECTIVE

We sought to compare history-indicated placement of cervical cerclage based on history- vs ultrasound-indicated placement in women at risk of preterm birth.

STUDY DESIGN

We conducted a randomized controlled trial of history-indicated cervical cerclage suture based on history (clinician preference) vs ultrasound (< 20 mm cervical length) indicated in women at increased risk.

RESULTS

The incidence of the primary outcome, preterm delivery between 24(+0) and 33(+6) weeks, was similar: 19/125 (15%) in the history-indicated group vs 18/122 (15%) in the ultrasound-indicated group (relative risk [RR], 0.97; 95% confidence interval [CI], 0.54-1.76). Those women randomized to the ultrasound-indicated arm were significantly more likely to receive a cerclage (32% vs 19%; RR, 1.66; 95% CI, 1.07-2.47) and progesterone (39% vs 25%; RR, 1.55; 95% CI, 1.06-2.25).

CONCLUSION

Screening women at high risk with cervical ultrasound to determine cerclage placement results in more intervention but similar outcome compared with history-indicated placement.

Novel developments on cervical length screening and progesterone for preventing preterm birth

Cervical length (CL) measured by transvaginal ultrasound is an effective screening test for the prevention of preterm birth (PTB). The criteria for an effective screening test are all met by CL. It studies an important condition (PTB); it is safe and acceptable by >99% of women; it recognises an early asymptomatic phase that precedes PTB by many weeks; it has a well-described technique, is reproducible, is predictive of PTB in all populations studies so far; and, perhaps most importantly, it has been shown that 'early' treatment is effective in prevention. These two interventions, effective only in specific populations, are ultrasound-indicated cerclage and vaginal progesterone.

Ultrasound-predicated versus history-predicated cerclage in women at risk of cervical insufficiency: a systematic review

The aim of this systematic review was to compare pregnancy outcomes and cerclage-related complications of ultrasound-predicated versus history-predicated cerclage in patients at risk of cervical insufficiency due to a history of preterm delivery (PTD). A structured search was performed in PubMed, Embase, and the Cochrane Library to identify potentially relevant articles from January 1980 through July 2007. Studies were included if ultrasound-predicated cerclage was compared to history-predicated cerclage in women with a singleton gestation and a history of PTD. The PubMed, Embase, and Cochrane search yielded 537, 643, and 42 articles, respectively. In addition, 1194 "Related articles" (PubMed) and 87 "Cited in/cited by" (ISI-WOS) from all potentially relevant articles were assessed. After critical evaluation for relevance and quality, 6 articles remained. Five of the 6 included studies showed no differences in pregnancy outcome (PTD or pregnancy loss <24 weeks) between the ultrasound-predicated and the history-predicated cerclage groups. In 1 prospective cohort study, PTD below 30 weeks was significantly lower in the ultrasound group. The included studies showed that in the ultrasound group, 40% to 68% of the patients did not require cerclage. The majority of studies provided insufficient data to draw conclusions regarding cerclage-related complications. In conclusion, using ultrasound to identify women at risk of cervical insufficiency because of a history of PTD reduces cerclage rates and results in similar pregnancy outcomes as cerclage placement on the basis of history alone.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After reading this article, the reader should be able to identify his or her own management of women with prior history of preterm delivery with respect to the possible use of cerclage, design a diagnostic strategy for his or her own patients to determine whether history or ultrasound-based decision making is appropriate in the practice setting, and translate best-practices with respect to definition of cervical shortening in his or her own practice.

Contemporary Use of Cervical Cerclage

Although it was devised over 50 years ago, only recently controlled randomized trials have evaluated the efficacy of cervical cerclage. Cerclage was originally devised for women with both prior preterm birth (PTB) and cervical changes in the current pregnancy. Evidence suggests that transvaginal cerclage probably prevents second trimester loss/PTB in women with >or=3 PTB/second trimester loss (history-indicated cerclage best placed at 12 to 14 wk); and in women with a prior PTB 16 to 36 weeks and transvaginal ultrasound cervical length<25 mm in the current pregnancy (ultrasound-indicated cerclage at 14 to 23 6/7 wk).

[What should you tell a patient with a history of cervical incompetence in the first trimester?]

Data is now more than ever available to inform couples at risk of second trimester miscarriage or preterm delivery. We are able to give customized information according to the obstetrical history and to the evolution of the cervix during the second trimester although the level of scientific evidence is limited or poor. Elective cerclage can be proposed to patients with a history of at least 3 second trimester miscarriages or preterm deliveries. There is no clear consensus on which patients could benefit from therapeutic cerclage. Indications would have to be motivated by a short cervix on ultrasound measurements and the cerclage performed before 24 weeks of gestation.

Strategies for prevention-cervical cerclage

Transvaginal cervical cerclage was introduced as a treatment for cervical incompetence in 1951. Over the years, our understanding of this clinical entity has changed tremendously, which has implications for obstetric management. This review focuses on the obstetric management of women considered to be at high risk of preterm delivery due to cervical incompetence at different stages of pregnancy.

Controversies regarding cervical incompetence, short cervix, and the need for cerclage

Cervical incompetence (CI) is not an all or nothing phenomenon but a continuous variable. CI and preterm labor are not distinct entities but rather part of a spectrum leading to preterm delivery. Cervical length (CL) is an independent variable in the prediction of preterm delivery, to which it is inversely related. Application of a primary transvaginal cervical cerclage appears to be an unnecessary intervention in about 50% of women presenting with a history suggesting cervical incompetence. A better alternative for women with a history of or risk factors for CI is transvaginal ultrasonographic follow-up of CL. To facilitate the comparison of studies of CI, the authors suggest a nomenclature reflecting the different stages of prevention: primary, secondary, and tertiary transvaginal cervical cerclage.

Effectiveness of cervical cerclage for a sonographically shortened cervix: a systematic review and meta-analysis

OBJECTIVE

The purpose of this study was to determine the effectiveness of cerclage for a shortened cervix on transvaginal ultrasound scanning in terms of the rates of preterm delivery and adverse neonatal and maternal outcomes.

STUDY DESIGN

Pre-MEDLINE and MEDLINE, EMBASE, and the Cochrane Library were searched for human studies that compared cerclage placement to no cerclage on the basis of transvaginal ultrasound findings of a short cervix (< or =2.5 cm). Two authors independently determined eligibility and abstracted data. Meta-analyses were conducted when possible.

RESULTS

Thirty-five studies were reviewed; 6 studies were eligible and were included in the analysis. There was no statistically significant effect of cerclage on the rates of preterm delivery (<37, <34, <32, and <28 weeks of gestation), preterm labor, neonatal mortality or morbidity, gestational age at delivery, or time to delivery. Birth weight was significantly higher with than without cerclage (P=.004).

CONCLUSION

The available evidence does not support cerclage for a sonographically detected short cervix. A randomized controlled trial is needed to determine whether this intervention will reduce adverse neonatal outcomes.

Patients with prior second-trimester loss: prophylactic cerclage or serial transvaginal sonograms?

OBJECTIVE

To compare management with prophylactic cerclage versus serial transvaginal sonograms of the cervix in patients with prior second-trimester loss.

STUDY DESIGN

Singleton pregnancies with prior second-trimester spontaneous loss between 14 and 24 weeks' gestation were retrospectively reviewed. At the obstetricians' discretion, some were managed with prophylactic cerclage and some with serial transvaginal sonograms of the cervix, starting at 14 weeks, and cerclage only if cervical length was <25 mm or funneling was >25% before 24 weeks. All cerclages were McDonald. Primary outcome was preterm delivery at <35 weeks.

RESULTS

Of 177 patients with singleton pregnancies who had prior second-trimester loss identified, 66 received prophylactic cerclage and 111 were followed up with transvaginal sonography, of which 36% (40/111) had therapeutic cerclage because of cervical changes. The two management groups of prophylactic cerclage versus transvaginal sonography of the cervix did not differ in any measure of obstetric outcome, including preterm delivery at <35 weeks (23% vs 30%; P =.3), preterm delivery at <33 weeks (21% vs 26%; P =.5), or gestational age at delivery (34.6 +/- 6.8 weeks vs 34.4 +/- 6.8 weeks; P =.8).

CONCLUSION

In patients with prior second-trimester loss, serial transvaginal sonography of the cervix, with cerclage only if indicated by cervical changes, is a valuable alternative to a policy of uniform prophylactic cerclage.

Cervical incompetence: a reappraisal of an obstetric controversy

Cervical incompetence is not a categoric but rather a continuous variable, meaning that there are various degrees in the competency of the cervix. Furthermore, a certain degree of competency of the cervix can be expressed differently in subsequent pregnancies. Women with risk factors for cervical incompetence in their gynecological/obstetric history should be followed by transvaginal ultrasonography. History alone is not an indication for a prophylactic cerclage. Although transvaginal ultrasonography identifies women at high risk of preterm delivery, it does not discriminate between different underlying pathologies. Short cervical length alone is not an indication for a therapeutic cerclage. Serial transvaginal ultrasonographic measurements of cervical length in women with risk factors can identify those women truly at high risk of preterm delivery. A transvaginal cervical cerclage with bed rest reduces preterm delivery and improves perinatal outcome in women with a short cervical length and risk factors for cervical incompetence.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to define cervical incompetence, explain the role of transvaginal ultrasonography in the prediction of preterm delivery, and summarize the data on the use of transvaginal cervical cerclage.

Cervical screening for preterm delivery

The ability of sonographic cervical length screening to detect those at risk of spontaneous preterm delivery has been extensively explored over the past few years. This applies both to high-risk and low-risk groups. Cervical length measurement appears to be superior to biochemical, microbiological or hormonal methods of screening. The screening technique has been standardized, but the cervical length for intervention and the timing and nature of intervention have not been defined. Cervical cerclage appears to be of use to prevent or arrest the progress of cervical dilation in high-risk cases, but the management of the screen-positive low-risk case has yet to be determined. Future management may be stratified according to actual cervical length, and prospective randomized trials of treatment for the short cervix are needed.