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

Effects of Amnioreduction before Physical Examination-Indicated Cerclage on Pregnancy Outcomes: A Propensity Score Matched Study

This study investigated the effects of amnioreduction before physical examination-indicated cerclage on pregnancy outcomes using a propensity score matching analysis. This multicenter retrospective cohort study included women who underwent cerclage operations due to painless cervical dilation in the second trimester (14-28 weeks). The primary outcome was the time from operation until delivery. Secondary outcomes included preterm birth rate and neonatal outcomes. Primary and secondary outcomes were compared between those with amnioreduction and those without amnioreduction. Of 103 women, 31 received preoperative amnioreduction (amnioreduction group) and 72 women did not (no-amnioreduction group). Since there were differences in baseline characteristics and preoperative ultrasound findings between the two groups, we matched 25 women with amnioreduction and 25 women without amnioreduction using a propensity score. In the matched cohort, the amnioreduction group showed a shorter time from operation to delivery than the group without amnioreduction and the hazard ratio of amnioreduction was 2.5 (95% confidence interval; 1.4-4.7). In addition, the preterm birth rate before 28 weeks of gestation and the neonatal composite outcome were higher in the amnioreduction group than that in the group without amnioreduction. Amnioreduction before physical examination-indicated cerclage was associated with poor pregnancy and neonatal outcomes. Therefore, careful consideration is required when performing amnioreduction before cerclage operation.

Cervical length distribution and other sonographic ancillary findings of singleton nulliparous patients at midgestation

BACKGROUND

Short cervix at midgestation, the presence of intraamniotic debris, and cervical funneling are risk factors for preterm birth; however, cervical length measurements and cutoffs are not well documented among pregnant patients of different gestational ages and self-reported races and ethnicities.

OBJECTIVE

This study aimed to describe the distribution of cervical length and frequency of funneling and debris at midgestation in nulliparous women by gestational age and race/ethnicity.

STUDY DESIGN

This secondary analysis of screening data from a multicenter treatment trial of singleton nulliparous patients with short cervix was conducted at 14 geographically distributed, university-affiliated medical centers in the United States. Singleton nulliparous patients with no known risk factors for preterm birth were screened for trial participation and asked to undergo a transvaginal ultrasound to measure cervical length by a certified sonographer. The distribution of cervical length and the frequency of funneling and debris were assessed for each gestational age week (16-22 weeks) and stratified by self-reported race and ethnicity, which for this study were categorized as White, Black, Hispanic, and other. Patients enrolled in the randomized trial were excluded from this analysis.

RESULTS

A total of 12,407 nulliparous patients were included in this analysis. The racial or ethnic distribution of the study participants was as follows: White, 41.6%; Black, 29.6%; Hispanic, 24.2%; and others, 4.6%. The 10th percentile cervical length for the entire cohort was 31.1 mm and, when stratified by race and ethnicity, 31.9 mm for White, 30.2 mm for Black, 31.4 mm for Hispanic, and 31.2 mm for patients of other race and ethnicity (P<.001). At each gestational age, the cervical length corresponding to the tenth percentile was shorter in Black patients. The 25 mm value commonly used to define a short cervix and thought to represent the 10th percentile ranged from 1.3% to 5.4% across gestational age weeks and 1.0% to 3.8% across race and ethnicity groups. Black patients had the highest rate of funneling (2.6%), whereas Hispanic and Black patients had higher rates of intraamniotic debris than White and other patients (P<.001).

CONCLUSION

Black patients had shorter cervical length and higher rates of debris and funneling than White patients. The racial and ethnic disparities in sonographic midtrimester cervical findings may provide insight into the racial disparity in preterm birth rates in the United States.

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.

Outcome of pregnancy with history-indicated cervical cerclage insertion in a low-resource setting

OBJECTIVE

History-indicated cervical cerclage insertion is required when factors in a woman's history could predispose to spontaneous miscarriage or preterm birth. This retrospective study determined the pregnancy outcome after insertion of history-indicated cervical cerclage for at least one previous mid-trimester spontaneous abortion over a 10-year period in a low-resource setting.

METHODS

This was a retrospective analysis of hospital data. Data was retrieved on biosocial and obstetrics parameters and analysed. The outcome measures were recurrence of spontaneous miscarriage, preterm delivery rate and fetal salvage rate. Descriptive frequencies were used to present results. The test of statistical significance was with Yates' coefficient correlation at 95% confidence interval.

RESULTS

Cervical cerclage rate was 7 per 1000 births. Diagnosis was clinical and cerclage was inserted at a mean gestational age of 15 ± 3.6 weeks. Hospital admission greater than five days after cerclage insertion had no statistically significant difference on preterm delivery (CI 95%; p value = 0.98). Repeat spontaneous miscarriage occurred less (5.6%) after cerclage insertion, fetal salvage rate was 75% and the preterm birth rate was 30%.

CONCLUSION

The limitations of the study notwithstanding, use of history-indicated cervical cerclage in pregnancy resulted in better fetal salvage rate and reduced recurrence of spontaneous miscarriage.

Use of cerclage in triplet pregnancies with an asymptomatic short cervix

OBJECTIVES

The purpose of this study was to compare the outcomes of triplet pregnancies in women with asymptomatic cervical shortening with and without a cervical cerclage.

METHODS

A retrospective review of all triplet pregnancies with biweekly serial cervical length surveillance was performed. Cervical shortening was defined as a cervical length of 2.5 cm or less before 24 weeks' gestation. Patients with cervical shortening managed with cerclage were compared to those managed expectantly. The primary outcome was the gestational age at delivery, with secondary outcomes including birth weight, neonatal intensive care unit length of stay, and composite neonatal outcome. Statistical significance was defined as P < .05.

RESULTS

Sixteen patients underwent cerclage placement versus 8 managed expectantly (control group). The median gestational ages at delivery were similar between the groups (cerclage, 31.3 weeks; interquartile range [IQR], 29.3-32.3 weeks; control, 29.8 weeks; IQR, 27.5-32.4 weeks; P = .71). The median birth weights were also similar between the groups (cerclage, 1283 g; IQR, 800-1626 g; control, 1109 g; IQR, 776-1500 g; P = .54). There was no significant difference in composite neonatal outcomes between the cerclage and control groups (P = .67).

CONCLUSIONS

In this limited case-control study, we found no benefit in terms of pregnancy prolongation or neonatal outcomes with cerclage placement for triplet gestations complicated by an asymptomatic short cervix.

[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.

Cervical pessary for preventing preterm birth

BACKGROUND

Preterm birth is a major health problem and contributes to more than 50% of the overall perinatal mortality. Preterm birth has multiple risk factors including cervical incompetence and multiple pregnancy. Different management strategies have been tried to prevent preterm birth, including cervical cerclage. Cervical cerclage is an invasive technique that needs anaesthesia and may be associated with complications. Moreover, there is still controversy regarding the efficacy and the group of patients that could benefit from this operation. Cervical pessary has been tried as a simple, non-invasive alternative that might replace the above invasive cervical stitch operation to prevent preterm birth.

OBJECTIVES

To evaluate the efficacy of cervical pessary for the prevention of preterm birth in women with risk factors for cervical incompetence.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (1 September 2012), Current Controlled Trials and the Australian New Zealand Clinical Trials Registry (1 September 2012).

SELECTION CRITERIA

We selected all published and unpublished randomised clinical trials comparing the use of cervical pessary with cervical cerclage or expectant management for prevention of preterm birth. We did not include quasi-randomised trials. Cluster-randomised or cross-over trials were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion.

MAIN RESULTS

The review included one randomised controlled trial. The study included 385 pregnant women with a short cervix of 25 mm or less who were between 18 to 22 weeks of pregnancy. The use of cervical pessary (192 women) was associated with a statistically significantly decrease in the incidence of spontaneous preterm birth less than 37 weeks' gestation compared with expectant management (22% versus 59 %; respectively, risk ratio (RR) 0.36, 95% confidence interval (CI) 0.27 to 0.49). Spontaneous preterm birth before 34 weeks was statistically significantly reduced in the pessary group (6% and 27% respectively, RR 0.24; 95% CI 0.13 to 0.43). Mean gestational age at delivery was 37.7 + 2 weeks in the pessary group and 34.9 + 4 weeks in the expectant group. Women in the pessary group used less tocolytics (RR 0.63; 95% CI 0.50 to 0.81) and corticosteroids (RR 0.66; 95% CI 0.54 to 0.81) than the expectant group. Vaginal discharge was more common in the pessary group (RR 2.18; 95% CI 1.87 to 2.54). Among the pessary group, 27 women needed pessary repositioning without removal and there was one case of pessary removal. Ninety-five per cent of women in the pessary group would recommend this intervention to other people. Neonatal paediatric care admission was reduced in the pessary group in comparison to the expectant group (RR 0.17; 95% CI 0.07 to 0.42).

AUTHORS' CONCLUSIONS

The review included only one well-designed randomised clinical trial that showed beneficial effect of cervical pessary in reducing preterm birth in women with a short cervix. There is a need for more trials in different settings (developed and developing countries), and with different risk factors including multiple pregnancy.

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.

Laparoscopic cervicoisthmic cerclage: technique and systematic review of the literature

BACKGROUND AND AIMS

To report on and review the outcome after laparoscopic cervicoisthmic cerclage (LCC) and robotic-assisted laparoscopic cervicoisthmic cerclage.

METHODS

We reported on 4 cases of LCC and conducted a systematic review of the literature up to May 2012 to identify obstetric outcomes after LCC and robotic-assisted LCC.

RESULTS

The median age of our series was 35 years (range: 31-41) with median previous pregnancies 3.5 (2-5). All 4 women had successful obstetric outcomes with a median gestational age at delivery of 37 weeks (range: 36-38). The systematic review identified 25 studies (162 women underwent LCC and 3 had robotic-assisted LCC). In the interval LLC studies, the median age was 33 years (range: 22-42); with a median gestational age at delivery of 37 weeks (range: 34-38). For prophylactic LCC, the median age was 31 years (range: 27-41); with a gestational age at delivery of 37 weeks (range: 19-39). Two of the three robotic-assisted LCC procedures were done prophylactically. The median age was 27 years (range: 23-37) with a median gestational age at delivery of 37 weeks (range: 35-38).

CONCLUSION

LCC is feasible during and in between pregnancies as well as in congenitally malformed uteri. Current evidence suggests that LCC might be of benefit in selected cases of cervical insufficiency with short cervices.

Sonographic cervical length measurement in pregnant women with a cervical pessary

OBJECTIVES

The aims of this study were to describe and assess the feasibility of measuring cervical length by standard transvaginal sonography (TVS) and transperineal sonography (TPS) in women with a cervical pessary and compare these measurements with those obtained with a new transvaginal technique.

METHODS

Measurement of cervical length by TPS was attempted immediately before measurement using TVS in 48 women with a cervical pessary at between 22 and 23 weeks' gestation. The TVS procedure consisted of two types of measurement: in the first, the probe was placed on the anterior fornix (standard technique) and in the second, the probe was inserted into the pessary to touch the anterior cervical lip (new technique). Two physicians consecutively performed these procedures and compared the measurements obtained. Intraclass correlation coefficients (ICCs) with 95% CI were used to evaluate interobserver reliability, and Bland-Altman analysis was used to assess interobserver agreement.

RESULTS

In total, 258 measurements (obtained from 43 women) were analyzed. Interobserver ICCs of the measurements obtained were 0.58 (95% CI, 0.34-0.75) for TPS, 0.65 (95% CI, 0.44-0.79) for the standard TVS technique and 0.97 (95% CI, 0.95-0.98) for the new TVS technique. Bland-Altman analysis showed small mean differences between measurements obtained by two physicians for the three methods, but with narrower limits of agreements (LOA) for the new TVS technique: TPS mean difference - 0.99 mm (95% LOA, - 13.23 to 11.25 mm), standard TVS technique mean difference - 0.23 mm (95% LOA, - 10.90 to 10.44 mm) and new TVS technique mean difference - 0.01 mm (95% LOA, - 2.57 to 2.55 mm). It was apparent from the images obtained that the external os was not visible in 89% of cases when either the TPS or standard TVS technique was used. However, the external os was visible in all cases when the new TVS method was used.

CONCLUSIONS

We propose a new technique for measuring and monitoring cervical length in women with a cervical pessary that provides improved visualization of the cervix and increased reliability in comparison to established techniques.

Cervical pessary for preventing preterm birth

BACKGROUND

Preterm delivery is a major health problem and contributes to more than 50% of the overall perinatal mortality. Cervical incompetence is one of the common causes of preterm birth to which different management strategies have been tried including cervical cerclage. Cervical cerclage is an invasive technique that needs anaesthesia and may be associated with complications. Moreover, there is still a matter of controversy regarding the efficacy and the group of patients which could benefit from this operation. Cervical pessary has been tried as a simple, non-invasive alternative that might replace the above invasive cervical stitch operation.

OBJECTIVES

To evaluate the efficacy of cervical pessary for prevention of preterm birth in women with cervical incompetence.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2010), Current Controlled Trials and the Australian New Zealand Clinical Trials Registry (May 2010).

SELECTION CRITERIA

We selected all published and unpublished randomised clinical trials comparing the use of cervical pessary with cervical cerclage or expectant management for prevention of preterm birth. We did not include quasi-randomised trials, cluster-randomised and crossover trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion.

MAIN RESULTS

The search identified two trials which we excluded. Three additional trials are ongoing. This review contains no included studies.

AUTHORS' CONCLUSIONS

The review did not identify any well-designed randomised clinical trial in order to confirm or refute the benefit of cervical pessary. However, there is evidence from non-randomised trials that showed some benefit of cervical pessary in preventing preterm birth. We are waiting for the results of three ongoing randomised controlled trials, assessing the role of cervical pessary in women with short cervix. There is a need for further well-designed randomised controlled trials.

Comparison of biochemical markers and cervical length for predicting preterm delivery

AIM

To examine the clinical utility of several prognostic factors for predicting preterm delivery.

METHODS

One hundred and nineteen patients with a singleton pregnancy admitted to our hospital because of symptoms of preterm labor were included in this study. Maternal serum C-reactive protein (CRP), transvaginal sonographic measurement of cervical length (CL), granulocyte elastase (EL) in cervical secretions, fetal fibronectin (fFN), alpha-fetoprotein (AFP), and insulin-like growth factor binding protein-1 (IGFBP-1) in vaginal secretions were examined on admission. EL, fFN, AFP, and IGFBP-1 were measured by bed-side test kits. Correlation between each factor and the duration of pregnancy (from admission to delivery) was investigated.

RESULTS

A significant correlation was found between the duration of pregnancy and CRP (r= -0.37, P<0.001), but not CL. The duration was significantly shorter in the fFN-positive group than in the negative group (P=0.0015). However, no significant difference was observed between the positive group and the negative group for each of CL, EL, AFP and IGFBP-1.

CONCLUSION

Association between the duration of the pregnancy and two biochemical markers (CRP and fFN) was confirmed. As they can be examined quickly and easily, they are quite useful for estimating prognosis of preterm labor.

Management of painless mid-trimester cervical dilatation: Prophylactic vs emergency placement of cervical cerclage

Women with recurrent painless mid-trimester miscarriages are often diagnosed with cervical insufficiency. Presenting symptoms typically include vaginal pressure and minimal bleeding; when the cervix is examined, advanced dilatation is usually detected. Labour is short and the premature fetus is born alive. Women with this history were traditionally considered candidates for the placement of cervical cerclage. Recently, this practice has been called into question. Rather than routine placement of prophylactic cervical cerclage at 12 - 14 weeks, many patients are followed expectantly with serial sonographic assessments of cervical length. The goal of this update is to review the literature regarding management options of mid-trimester cervical dilatation.

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

OBJECTIVE

The objective of the study was to determine the value of serial ultrasonographic cervical length (CL) measurements after cerclage to predict preterm delivery.

STUDY DESIGN

Retrospective ultrasonographic and outcome data from singleton pregnancies with cerclage were reviewed. Using transvaginal ultrasound (TVS), overall CL obtained before cerclage placement, 2 weeks after cerclage, and before delivery were compared between women who delivered preterm (less than 37 weeks) and term. The overall CL including CL above (CLA) and below the cerclage (CLB) were compared using the SAS program.

RESULTS

Cerclage was placed at 15.7 +/- 3.6 weeks (mean +/- SD) in 57 women. The overall CL before cerclage, 2 weeks after cerclage, and the last TVS before delivery was not different in preterm and term births. The odds ratio of a measurable CLA for preterm delivery by TVS was 0.87 (0.78 to 0.95, 95% confidence interval). Thirty-two patients (56%) had absent CLA at 26.7 +/- 4.4 weeks. Of these, 16 (50%) were delivered for preterm premature rupture of membranes (PPROM) and chorioamnionitis (sensitivity of 100%, specificity of 61%, positive predictive value of 50%, and negative predictive value of 100%).

CONCLUSION

Although the overall cervical length by serial TVS after cerclage did not predict preterm birth, absent CLA is associated with preterm delivery, chorioamnionitis, and PPROM.

Feasibility of a randomized controlled trial testing nifedipine vs. placebo for the treatment of preterm labor

AIMS

Nifedipine is believed to be a superior tocolytic agent on the basis of efficacy and side-effect profile, but was never prospectively evaluated in a placebo-controlled randomized clinical trial (RCT). In our study, we sought to identify limitations in participation for a would-be RCT comparing nifedipine to placebo.

METHODS

A prospective feasibility study was conducted at Ste-Justine Hospital, a tertiary care center, on women between 24 and 34 weeks' gestation, presenting to the labor and delivery room with obstetrical complaints. Patient information was collected and would-be participants were identified on the basis of pre-established clinical and ultrasound criteria as well as on willingness to participate, as determined by the study research nurse.

RESULTS

During a 6-month period, 483 women presenting with signs and symptoms of preterm labor (PTL) were eligible for further evaluation. A total of 321 (66.5%) women were excluded for obstetrical and medical reasons whereas 125 (25.9%) did not meet strict inclusion criteria (cervical length <25 mm or positive fetal fibronectin). When using strict criteria, only 37 women (7.6%) were found to be eligible for study participation. Subject willingness to participate as assessed by the research nurse was 50%.

CONCLUSIONS

If adhering to strict inclusion/exclusion criteria, the feasibility of an appropriately sampled RCT testing tocolytic therapy against a placebo would require a large concerted multicenter effort to meet sample size demands.

Cervical length < or = 25 mm in low-risk women: a case control study of cerclage with rest vs rest alone

OBJECTIVE

The purpose of this study was to evaluate the clinical utility of cerclage in low risk women with cervical length (CL) < or = 25 mm at transvaginal ultrasound (TVU).

STUDY DESIGN

This was a retrospective cohort study of women with CL < or = 25 mm identified incidentally at TVU examinations between 16(0/7) to 24(6/7) weeks, with no history of previous preterm birth or midtrimester losses. The primary study outcome was rate of preterm delivery < 35 weeks' gestation.

RESULTS

Women undergoing cerclage placement (n = 31) had shorter CL (P < .001) and lower gestational age at presentation (P < .001) than those managed with rest alone (n = 36). Gestational age at delivery was 37.6 +/- 3.6 vs 38.5 +/- 2.1 weeks (P = .17), and delivery at < 35 weeks occurred in 5/31 versus 2/36 cases, respectively (P = .23). The lack of a significant association between cerclage and rate of delivery < 35 weeks persisted after controlling for gestational age at TVU and initial CL (P = .81).

CONCLUSION

Cerclage placement does not improve pregnancy outcome in low-risk women with incidental detection of CL < or = 25 mm in the early second trimester.

Recurrent preterm birth

Recurrent preterm birth is frequently defined as two or more deliveries before 37 completed weeks of gestation. The recurrence rate varies as a function of the antecedent for preterm birth: spontaneous versus indicated. Spontaneous preterm birth is the result of either preterm labor with intact membranes or preterm prelabor rupture of the membranes. This article reviews the body of literature describing the risk of recurrence of spontaneous and indicated preterm birth. Also discussed are the factors which modify the risk for recurrent spontaneous preterm birth (a short sonographic cervical length and a positive cervicovaginal fetal fibronectin test). Patients with a history of an indicated preterm birth are at risk not only for recurrence of this subtype, but also for spontaneous preterm birth. Individuals of black origin have a higher rate of recurrent preterm birth.

Cervical cerclage in the prevention of preterm birth

Cervical cerclage has been used in the management of cervical insufficiency for several decades, yet the indications are uncertain and benefits marginal. It remains a controversial intervention. The diagnosis of cervical insufficiency is traditionally based on a history of recurrent second trimester miscarriages, or very preterm delivery whereby the cervix is unable to retain the pregnancy until term. Cervical cerclage has been the subject of many observational and randomised controlled trials. This article reviews the literature regarding the effectiveness of elective or emergency transvaginal cerclage and transabdominal cerclage.

Preterm labour. Cervical function and prematurity

The cervix maintains the fetus in situ during pregnancy and dilates during labour to allow delivery of the baby. Congenital or iatrogenically-induced structural abnormalities of the cervix are associated with an increased risk of preterm birth. The role of cervical infection is less clear. Cervical studies may be useful in the prediction of preterm delivery: both a shortened cervical length identified on transvaginal ultrasound examination and an increased level of fetal fibronectin in cervico-vaginal secretions are associated with an increased risk of preterm delivery. In singleton pregnancy, cervical cerclage reduces the risk of preterm birth by 25%. There is no evidence of a reduction in neonatal mortality or morbidity, and the beneficial effects of preterm birth reduction have to be set against the increased risk of maternal infection. Neither the American College of Obstetricians and Gynecologists (ACOG) nor the Royal College of Obstetricians and Gynaecologists (RCOG) has unequivocally endorsed cervical cerclage. Further work is required to define the role of the cervix in prediction and prevention of spontaneous preterm birth.

PREMATURE CERVICAL CHANGE AND THE USE OF CERVICAL CERCLAGE

Preterm birth and its subsequent consequences continue to be a major challenge worldwide. In the United States in 2004, 12.5% of infants were born preterm, making the annual societal economic burden associated with preterm birth in excess of $26.2 billion (and this is a modest estimate). Spontaneous preterm birth accounts for about 75% of all preterm births; however, at earlier gestations iatrogenic preterm birth accounts for a greater proportion of all preterm births; at 27–28 weeks 50% are iatrogenic. The proportion of babies transferred to the neonatal unit is more than 90% for those born before 33 completed weeks of gestation compared with 31% at 36 weeks; delivery between 33 completed weeks and 36 completed weeks has a relatively low morbidity and mortality. Nonetheless, 1 in 3 children born preterm but beyond 32 weeks have educational and behavioural problems at the age of 7, with 1 in 4 children born between 32 and 35 weeks requiring support from non-teaching assistants at school. Although more than 40% of babies at 35 completed weeks show signs of maturity, some still need ventilation at 38 completed weeks. Almost one-fifth of all infants born at less than 32 weeks gestation do not survive the first year of life.

Do screening-preventative interventions in asymptomatic pregnancies reduce the risk of preterm delivery—A critical appraisal of the literature

Recent research has suggested that women who experience preterm delivery (PTD) may be identified earlier in pregnancy and before onset of symptoms. Interventions commenced at this earlier asymptomatic stage may offer an opportunity to prevent PTD or lengthen gestation sufficiently to reduce adverse perinatal outcome. Our objective was to examine the evidence that supports or refutes this approach to preventing PTD. We therefore conducted a systematic search and critical appraisal of the identified literature. We found evidence that introducing screening-preventative strategies for asymptomatic pregnancies may reduce the rate of PTD. Evidence for screening and selective treatment exists for: asymptomatic bacteriuria; bacterial vaginosis in low-risk population groups; elective cervical cerclage in high-risk pregnancies; indicated cervical cerclage in women with short cervical length on ultrasound; prophylactic progesterone supplementation in high-risk pregnancies, and smoking cessation. However, for most other strategies, such as increased antenatal attendance, or routine administration of prophylactic micronutrients, the evidence is inconsistent and conflicting. Information on neonatal outcomes apart from PTD (such as serious neonatal morbidity and mortality) was found to be lacking in most studies. It was therefore not possible to establish whether preventing PTD or prolonging gestation would correlate to improved perinatal outcome, and this lessened the potential clinical usefulness of any proposed preventative strategy. No studies were found that evaluated the effectiveness of combining screening-preventative strategies. The review concludes with a suggested an antenatal management plan designed to prevent PTD based on current practice and the evidence presented in this article.

The short and funneling cervix: when to use cerclage?

PURPOSE OF REVIEW

The diagnosis of cervical incompetence remains extremely difficult because there is no diagnostic test available prior to, during or after pregnancy. This review will summarize the latest publications on the use of transvaginal ultrasonography to identify women at high risk of preterm delivery and the use of cervical cerclage in these women.

RECENT FINDINGS

Cervical length is not only inversely related to the risk of preterm delivery but also inversely related to the risk of intrauterine infection in women with preterm labor. Furthermore, previous history of preterm delivery is related to the risk of preterm delivery. Cerclage trials on women with short cervical length present conflicting results both in low and high-risk populations. Assessment of risk factors and obstetric history remain important in the diagnosis of cervical incompetence. Women at high risk of preterm delivery due to cervical incompetence should be followed-up with transvaginal measurements of cervical length. Only a minority of these women will develop a short cervical length and will consequently be at high risk of preterm delivery.

SUMMARY

A combination of assessment of risk factors, obstetric history and follow-up of cervical length enables us to identify women who benefit from a cervical cerclage.

The role of cervical cerclage in obstetric practice: can the patient who could benefit from this procedure be identified?

This editorial critically examines the definition of "cervical insufficiency." The definition, the clinical ascertainment, efforts to develop an objective method of diagnosis, as well as the nature of cervical disease leading to spontaneous mid-trimester spontaneous abortion and preterm delivery are reviewed. The value and limitations of cervical sonography as a risk assessment tool for spontaneous preterm delivery are appraised. The main focus is on the role of cervical cerclage to prevent an adverse pregnancy outcome. The value of assessing the presence or absence of endocervical inflammation in the outcome of cerclage placement is discussed.

Cerclage for Short Cervix on Ultrasonography

OBJECTIVE

Preterm birth is the main cause of perinatal morbidity and mortality. A short cervical length on transvaginal ultrasonography predicts preterm birth. Our aim was to estimate by meta-analysis of randomized trials whether cerclage prevents preterm birth in women with a short cervical length.

DATA SOURCES

MEDLINE, PubMed, EMBASE, and the Cochrane Library were searched with the terms "cerclage," "cervical cerclage," "short cervix," "ultrasound," and "randomized trial." We included randomized trials involving the use of cerclage in women with short cervical length on transvaginal ultrasonography using patient-level data.

TABULATION, INTEGRATION, AND RESULTS

Four properly conducted trials were identified. In the total population, preterm birth at less than 35 weeks of gestation occurred in 29.2% (89/305) of the cerclage group, compared with 34.8% (105/302) of the no-cerclage groups (relative risk [RR] 0.84, 95% confidence interval [CI] 0.67-1.06). There was no significant heterogeneity in the overall analysis (P = .29). There was a significant reduction in preterm birth at less than 35 weeks in the cerclage group compared with the no-cerclage groups in singleton gestations (RR 0.74, 95% CI 0.57-0.96), singleton gestations with prior preterm birth (RR 0.61, 95% CI 0.40-0.92), and singleton gestations with prior second-trimester loss (RR 0.57, 95% CI 0.33-0.99). There was a significant increase in preterm birth at less than 35 weeks in twin gestations (RR 2.15, 95% CI 1.15-4.01).

CONCLUSION

Cerclage does not prevent preterm birth in all women with short cervical length on transvaginal ultrasonography. In the subgroup analysis of singleton gestations with short cervical length, especially those with a prior preterm birth, cerclage may reduce preterm birth, and a well-powered trial should be carried out in this group of patients. In contrast, in twins, cerclage was associated with a significantly higher incidence of preterm birth.

Cerclage for the short cervix demonstrated by transvaginal ultrasound: current practice and opinion

OBJECTIVES

(1) To elucidate the views of obstetricians with respect to the use of transvaginal ultrasound in general, and, specifically, for determining cervical length, and the conditions under which obstetricians would employ cervical cerclage based on a sonographically revealed shortened cervix; and (2) to determine the possibility of a randomized controlled trial on the use of cervical cerclage in this situation.

METHODS

A 7-item questionnaire in French and English was designed and pretested. Questionnaires were mailed to 1421 physicians identified in the Canadian Medical Directory as practising obstetricians/gynaecologists in Canada. Returned questionnaires were scanned into an Access database for simple descriptive analyses.

RESULTS

Responses were received from 766 physicians. Of these 766 respondents, 604 physicians indicated they continued to practise obstetrics and supplied information that was usable in the analysis. The majority of the 604 respondents (85.6%) reported that they would recommend transvaginal ultrasound only in pregnant women with 1 or more risk factors for preterm birth. Respondents were most likely to recommend a cerclage, and least unsure of their decision to do so, if the gestational age was less than 23 weeks, the cervical length was less than 1 cm, and additional risk factors for preterm birth were present. As gestational age and cervical length increased, respondents were less likely to recommend cerclage and more unsure of their decision to do so. The pattern of responses was similar for singleton and multiple pregnancies. The McDonald technique was favoured over the Shirodkar technique by 70.4% of the respondents who performed cervical cerclage procedures. Adjunctive antibiotics were used with cerclage by 52.5% and adjunctive tocolytics were employed by 37.4%. The majority (68.8%) of the respondents who performed cervical cerclage procedures stated that they would participate in a randomized controlled trial on the effectiveness of cerclage for a sonographically revealed short cervix.

CONCLUSION

In the case of a short cervix determined by ultrasound, there is significant uncertainty surrounding the decision whether to place a cerclage and considerable variation in the clinical practice on its placement. In the absence of good evidence to guide clinical practice, a randomized controlled trial is being planned.

What’s new and novel in obstetric anesthesia? Contributions from the 2003 scientific literature

THE PREGNANT PATIENT: Age; maternal disease; prophylactic antibiotics; gastroesophageal reflux; obesity; starvation; genotyping; coagulopathy; infection; substance abuse; altered drug responses in pregnancy; physiological changes of pregnancy. THE FETUS: Fetal monitoring; intrauterine surgery. THE NEWBORN: Breastfeeding; maternal infection, fever, and neonatal sepsis evaluation. OBSTETRIC COMPLICATIONS: Embolic phenomena; hemorrhage; preeclampsia; preterm delivery. OBSTETRIC MANAGEMENT: External cephalic version and cervical cerclage; elective cesarean delivery; fetal malpresentation; vaginal birth after cesarean delivery; termination of pregnancy. OBSTETRIC ANESTHESIA: Analgesia for labor and delivery; anesthesia for cesarean delivery; anesthesia for short obstetric operations; complications of anesthesia. MISCELLANEOUS: Consent; ethics; history; labor support; websites/books/leaflets/journal announcements.

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.

Cerclage for prevention of preterm birth in women with a short cervix found on transvaginal ultrasound examination: a randomized trial

OBJECTIVE

The purpose of this study was to determine the efficacy of cerclage and bed rest versus bed rest-only for the prevention of preterm birth in women with a short cervix found on transvaginal ultrasound examination.

STUDY DESIGN

Women with > or =1 of high-risk factors for preterm birth (> or =1 preterm birth at < 35 weeks of gestation, > or =2 curettages, diethylstilbestrol exposure, cone biopsy, Mullerian anomaly, or twin gestation) were screened with transvaginal ultrasonography of the cervix every 2 weeks from 14 weeks of gestation to 23 weeks 6 days of gestation. Enrollment was offered to both asymptomatic women who were at high risk and who were identified to have short cervix (< 25 mm) or significant funneling (>25%) and nonscreened women who were at low risk and who were identified incidentally. The women who gave written consent were assigned randomly to receive either McDonald cerclage or bed rest-only. Both groups received similar counseling and treatment. Primary outcome was preterm birth at < 35 weeks of gestation.

RESULTS

Sixty-one women were assigned randomly. Forty-seven pregnancies (77%) were high-risk singleton gestations. Thirty-one women (51%) were allocated to cerclage, and 30 women (49%) were allocated to bed rest. There were no differences between the groups in demographic characteristics, risk factors, and cervical variables. Preterm birth at < 35 weeks of gestation occurred in 14 women (45%) in the cerclage group and in 14 women (47%) in the bed rest group (relative risk, 0.94; 95% CI, 0.34-2.58). There was no difference in any obstetric or neonatal outcomes. A subanalysis of singleton pregnancies with previous preterm birth at < 35 weeks of gestation and a short cervix of < 25 mm (n = 31 women) also revealed no significant difference in recurrent preterm birth at < 35 weeks of gestation (40% vs 56%; relative risk, 0.52; 95% CI, 0.12-2.17).

CONCLUSION

Cerclage did not prevent preterm birth in women with a short cervix. These results should be confirmed by larger trials.