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

Early Magnetic Resonance Imaging Measurements and Prediction of Second Trimester Pregnancy Loss: a Nomogram Model Analysis

Objective

To investigate the magnetic resonance imaging (MRI) features of women with prior second-trimester pregnancy loss, and to establish a nomogram prediction model for subsequent miscarriage.

Methods

A retrospective cohort study of women with prior second-trimester pregnancy loss from January 2018 to December 2021 in Second Affiliated Hospital of Soochow University was performed. A total of 245 patients were included. Data from January 2018 to December 2019 were used to construct the model, and data from January 2020 to December 2021 were used to evaluate the model. Data on maternal demographic characteristics, MRI cervical measurements were extracted. The prediction model was constructed with independent variables determined by multivariate logistic regression analyses. Through receiver-operating characteristic (ROC) curve analysis, the predictive ability of the model for subsequent second trimester pregnancy loss in women was evaluated, and internal validation was performed through validation data.

Results

Thin cervix was observed in 77 (31.42%) women with prior second-trimester pregnancy loss, the mean longitudinal diameter of cervical canal on MRI was 11.76±2.75mm. The model reached a sensitivity of 80%, specificity of 75.90%, positive predictive value (PPV) of 55.80% and negative predictive value of 90.90%; ROC characteristics proved that the model was superior to any single parameter with an AUC of 0.826.

Conclusion

Our observations showed that thin cervix and longitudinal diameter of cervical canal reliably predicted second trimester pregnancy loss. We developed and validated a nomogram model to predict the individual probability of second trimester pregnancy loss in the next pregnancy and hopefully improve the prediction and indication of interventions.

Prevention of spontaneous preterm delivery – an update on where we are today

Spontaneous preterm birth (delivery before 37 completed weeks) is the single most important cause of perinatal morbidity and mortality. The rate is increasing world-wide with a great disparity between low, middle and high income countries. It has been estimated that the cost of neonatal care for preterm babies is more than 4 times that of a term neonate admitted into the neonatal care. Furthermore, there are high costs associated with long-term morbidity in those who survive the neonatal period. Interventions to stop delivery once preterm labor starts are largely ineffective hence the best approach to reducing the rate and consequences is prevention. This is either primary (reducing or minimizing factors associated with preterm birth prior to and during pregnancy) or secondary - identification and amelioration (if possible) of factors in pregnancy that are associated with preterm labor. In the first category are optimizing maternal weight, promoting healthy nutrition, smoking cessation, birth spacing, avoidance of adolescent pregnancies and screening for and controlling various medical disorders as well as infections prior to pregnancy. Strategies in pregnancy, include early booking for prenatal care, screening and managing medical disorders and their complications, and identifying predisposing factors to preterm labor such as shortening of the cervix and timely instituting progesterone prophylaxis or cervical cerclage where appropriate. The use of biomarkers such as oncofetal fibronectin, placental alpha-macroglobulin-1 and IGFBP-1 where cervical screening is not available or to diagnosis PPROM would identify those that require close monitoring and allow the institution of antibiotics especially where infection is considered a predisposing factor. Irrespective of the approach to prevention, timing the administration of corticosteroids and where necessary tocolysis and magnesium sulfate are associated with an improved outcome. The role of genetics, infections and probiotics and how these emerging dimensions help in the diagnosis of preterm birth and consequently prevention are exciting and hopefully may identify sub-populations for targeted strategies.

Cervical Cerclage: A Comprehensive Review of Major Guidelines

Importance

Cervical cerclage (CC) represents one of the few effective measures currently available for the prevention of preterm delivery caused by cervical insufficiency, thus contributing in the reduction of neonatal morbidity and mortality rates.

Objective

The aim of this study was to review and compare the most recently published major guidelines on the indications, contraindications, techniques, and timing of placing and removal of CC.

Evidence Acquisition

A descriptive review of guidelines from the American College of Obstetricians and Gynecologists (ACOG), the Royal College of Obstetricians and Gynaecologists (RCOG), the Society of Obstetricians and Gynaecologists of Canada (SOGC), and the International Federation of Gynecology and Obstetrics (FIGO) on CC was carried out.

Results

There is a consensus among the reviewed guidelines regarding the recommended techniques, the indications for rescue CC, the contraindications, as well as the optimal timing of CC placement and removal. All medical societies also agree that ultrasound-indicated CC is justified in women with history of prior spontaneous PTD or mid-trimester miscarriage and a short cervical length detected on ultrasound. In addition, after CC, serial sonographic measurement of the cervical length, bed rest, and routine use of antibiotics, tocolysis, and progesterone are unanimously discouraged. In case of established preterm labor, CC should be removed, according to ACOG, RCOG, and SOGC. Furthermore, RCOG and SOGC agree on the prerequisites that should be met before attempting CC. These 2 guidelines along with FIGO recommend history-indicated CC for women with 3 or more previous preterm deliveries and/or second trimester pregnancy miscarriages, whereas the ACOG suggests the use of CC in singleton pregnancies with 1 or more previous second trimester miscarriages related to painless cervical dilation or prior CC due to painless cervical dilation in the second trimester. The role of amniocentesis in ruling out intra-amniotic infection before rescue CC remains a matter of debate.

Conclusions

Cervical cerclage is an obstetric intervention used to prevent miscarriage and preterm delivery in women considered as high-risk for these common pregnancy complications. The development of universal international practice protocols for the placement of CC seems of paramount importance and will hopefully improve the outcomes of such pregnancies.

Analysis of pregnancy outcomes in patients undergoing ultrasound-indicated cerclage and identification the influence factors for predicting preterm birth: A retrospective study of 87 cases

OBJECTIVE

To investigate the factors influencing preterm birth in patients after ultrasound-indicated cerclage with different cervical lengths (CL), and explore the optimal cut-off value of CL.

MATERIALS AND METHODS

The retrospective study included 87 pregnant women with a history of preterm birth and second-trimester loss that received ultrasound-indicated cerclage in our hospital between January 2004 and April 2021. Groups were divided by CL at the demarcation point of 1.0, 1.5 and 2.0 cm respectively. The pregnancy outcomes were compared. Logistic regression analysis was performed to assess the independent influence factors. Receiver-operating characteristic (ROC) curves were constructed and the area under the curve (AUC) was used to compare the prediction capability of the associated factors.

RESULTS

Significant difference was found in terms of patients delivered at ≥32 weeks of gestation (19 [55.9%]vs. 41 [77.4%], p < 0.05) and neonatal birth weight (2495 [1138,3185]vs. 2995 [2155,3235] g, p < 0.05), when the CL was categorized at the demarcation point of 1.5 cm. Body mass index (BMI) (odds ratio [OR] = 1.224, p < 0.05), a history of preterm birth and second-trimester loss (OR = 3.153, p < 0.05), and C-reactive protein (CRP) > 5 mg/L (OR = 8.097, p < 0.05) were independent risk factors for gestational age more than 28 weeks. The AUC of joint predictor A included those factors was 0.849 (95% CI: 0.701-0.998, p < 0.05). CRP>5 mg/L was found to be a significant independent risk factor for different gestational age at delivery.

CONCLUSIONS

A CL of 1.5 cm was the optimal cut-off value that could help women who underwent serial CL surveillance choose ultrasound-indicated cerclage at an appropriate time. High BMI, more history of preterm birth and second-trimester loss and abnormal CRP could be used as combined predictors to recognize the risk of preterm birth (<28 weeks) post-surgery.

Analysis of maternal and neonatal outcomes using cervical cerclage or conservative treatment in singleton gestations with a sonographic short cervix

To investigate the effect of cervical cerclage or conservative treatment on maternal and neonatal outcomes in singleton gestations with a sonographic short cervix, and further compare the relative treatment value.A retrospective study was conducted among women with singleton gestations who had a short cervical length (<25 mm) determined by ultrasound during the period of 14 to 24 weeks' gestation in our institution. We collected clinical data and grouped the patients according to a previous spontaneous preterm birth (PTB) at <34 weeks of gestation or second trimester loss (STL) and sub-grouped according to treatment option, further comparing the maternal and neonatal outcomes between different groups.In the PTB or STL history cohort, the cerclage group had a later gestational age at delivery (35.3 ± 3.9 weeks vs 31.6 ± 6.7 weeks) and a lower rate of perinatal deaths (2% vs 29.3%) compared with the conservative treatment group. In the non-PTB-STL history cohort, the maternal and neonatal outcomes were not significantly different between the cerclage group and conservative treatment group. More importantly, for patients with a sonographic short cervix who received cervical cerclage, there was no significant difference in the maternal and neonatal outcomes between the non-PTB-STL group and PTB or STL group.For singleton pregnant with a history of spontaneous PTB or STL and a short cervical length (<25 mm), cervical cerclage can significantly improve maternal and neonatal outcomes; however, conservative treatment (less invasive and expensive than cervical cerclage) was more suitable for those pregnant women without a previous PTB and STL history.

Current Approaches to Risk Assessment and Prevention of Preterm Birth-A Continuing Public Health Crisis

Background: Preterm birth remains a major cause of neonatal morbidity and mortality. Several potential pathways and pathophysiologic processes can lead to preterm birth, complicating efforts to screen for the risk of preterm birth and making implementation of prevention strategies difficult.

Methods: Based on a review of the literature, this article addresses screening strategies for preterm birth risk stratification and interventions for preterm birth prevention.

Results: In women with a history of a prior spontaneous preterm birth, cervical cerclage placement in the setting of short cervix reduces the rate of recurrent spontaneous preterm birth. Weekly injections of 17-hydroxyprogesterone caproate (17-P) have been used as standard treatment for the prevention of recurrent preterm birth since 2011. However, results of a replication study of 17-P published in 2020 have raised questions regarding the effectiveness of this drug, and it is under review by the US Food and Drug Administration. Among women with no history of preterm birth, cervical length appears to be the best predictor of risk for preterm birth in asymptomatic women. In women with a cervical length <25 mm, vaginal progesterone has been demonstrated to reduce the risk of preterm birth.

Conclusion: Strategies including cervical length screening, vaginal progesterone administration, cervical cerclage placement, and, potentially, 17-P administration may help reduce rates of preterm birth when used in the appropriate patient populations. Development of protocols for patient evaluation and risk stratification will help identify patients at highest risk for preterm birth and allow use of the best available therapeutic interventions.

Patients with acute cervical insufficiency without intra-amniotic infection/inflammation treated with cerclage have a good prognosis

Background The frequency of intra-amniotic infection/inflammation (IAI/I) in patients with midtrimester cervical insufficiency is up to 50%. Our purpose was to determine the perinatal outcomes of cervical cerclage in patients with acute cervical insufficiency with bulging membranes, and to compare the admission-to-delivery interval and pregnancy outcomes according to the results of amniotic fluid (AF) analysis and cerclage placement. Methods This was a retrospective cohort study including singleton pregnancies with cervical insufficiency between 15 and 26.9 weeks in two tertiary health centers. IAI/I was defined when at least one of the following criteria was present in AF: (a) a white blood cell (WBC) count >50 cells/mm3; (b) glucose concentration <14 mg/dL; and/or (c) a Gram stain positive for bacteria. Three different groups were compared: (1) absence of IAI/I with placement of a cerclage; (2) amniocentesis not performed with placement of a cerclage; and (3) IAI/I with or without a cerclage. Results Seventy patients underwent an amniocentesis to rule out IAI/I. The prevalence of IAI/I was 19%. Forty-seven patients underwent a cerclage. Patients with a cerclage had a longer median admission-to-delivery interval (33 vs. 2 days; P < 0.001) and delivered at a higher median gestational age (27.4 vs. 22.6 weeks; P = 0.001) than those without a cerclage. The neonatal survival rate in the cerclage group was 62% vs. 23% in those without a cerclage (P = 0.01). Patients without IAI/I who underwent a cerclage had a longer median admission-to-delivery interval (43 vs. 1 day; P < 0.001), delivered at a higher median gestational age (28 vs. 22.1 weeks; P = 0.001) and had a higher neonatal survival rate (67% vs. 8%; P < 0.001) than those with IAI/I. Conclusion The pregnancy outcomes of patients with midtrimester cervical insufficiency and bulging membranes are poor as they have a high prevalence of IAI/I. Therefore, a pre-operative amniocentesis is key to identify the best candidates for the subsequent placement of a cerclage.

A comparison of emergency and therapeutic modified Shirodkar cerclage: an analysis of 38 consecutive cases

Objective:

To compare the maternal and neonatal outcomes of patients with emergency versus therapeutic cerclage.

Materials and Methods:

The study included 38 female patients who underwent cervical cerclage using the modified Shirodkar method in the Obstetrics and Gynecology Clinics of Düzce University Medical Faculty Hospital and Düzce Atatürk State Hospital.

Results:

The operating time for the emergency cerclage group was significantly longer than that of the therapeutic group (30.40 minutes vs 19.85 minutes, p=0.001). Following the cerclage procedure, the cervical length was longer in the therapeutic cerclage group [29.90 millimeters (mm) vs. 22.45 mm, p=0.001]. The cerclage to birth interval was also longer in the therapeutic group (91 vs. 138 days).

Conclusion:

In comparison with therapeutic cerclage, the total duration of pregnancy after emergency cerclage is shorter, and newborns have a greater need for intensive care. Both methods, however, protect against advanced prematurity, which causes neonatal loss.

Adjuvant 17-hydroxyprogesterone caproate in women with history-indicated cerclage: A systematic review and meta-analysis

INTRODUCTION

The purpose of this study was to evaluate whether there are additional benefits of 17-hydroxyprogesterone caproate (17-OHPC) supplementation in preventing recurrent spontaneous preterm birth in women with a prophylactic cerclage.

MATERIAL AND METHODS

Electronic databases (MEDLINE, Scopus, ClinicalTrials.gov, PROSPERO, EMBASE, Scielo and the Cochrane Central Register of Controlled Trials) were searched for studies published before June 2018. Keywords included "preterm birth", "prophylactic cerclage", "history-indicated cerclage", "pregnancy" and "17-hydroxyprogesterone caproate". Studies comparing history-indicated cerclage alone with cerclage+17-OHPC were included. The primary outcome measure was preterm birth at <24 weeks of gestation. Secondary outcome measures include preterm birth at <28 weeks, <32 weeks and <37 weeks of gestation, respiratory distress syndrome, necrotizing enterocolitis, fetal birthweight, neonatal intensive care unit stay, mean gestational age at delivery, fetal/neonatal death, neurological morbidity (intraventricular hemorrhage plus periventricular leukomalacia), neonatal sepsis and a composite of severe neonatal morbidity. Severe neonatal morbidity was defined as a composite measure of periventricular leukomalacia, intraventricular hemorrhage (grades III and IV), necrotizing enterocolitis or respiratory distress syndrome. Meta-analysis was performed using the random-effects model of DerSimonian and Laird. Risk of bias and quality assessment were performed using the ROBINS-I and GRADE tools, respectively. PROSPERO Registration Number: CRD42018094559.

RESULTS

Five studies met the inclusion criteria and were included in the final analysis. Of the 546 women, 357 (75%) received history-indicated cerclage alone and 189 (35%) received adjuvant 17-OHPC. The composite endpoint, severe neonatal morbidity, was present in 84 of 1515 neonates. Though there was a trend toward a reduced risk of preterm birth, the summary estimate of effect was not statistically significant when comparing cerclage alone with cerclage+17-OHPC at <24 weeks (relative risk [RR] .86, 95% confidence interval [CI] .45-1.65). Similarly, we found no differences in preterm birth at <37 weeks (RR .90, 95% CI .70-1.17) and <28 weeks (RR .85, 95% CI .54-1.32) when comparing cerclage alone with cerclage+17-OHPC. There were no differences in fetal birthweight, respiratory distress syndrome or necrotizing enterocolitis comparing cerclage alone with cerclage+17-OHPC.

CONCLUSIONS

Intramuscular 17-OHPC in combination with prophylactic cerclage in women with prior preterm birth had no synergistic effect in reducing spontaneous recurrent preterm birth or improving perinatal outcomes.

Cervical cerclage for singleton pregnant patients on vaginal progesterone with progressive cervical shortening

BACKGROUND

Premature cervical ripening plays a significant role in spontaneous preterm birth. Vaginal progesterone is the recommended treatment in singleton pregnancy with incidental short cervix. There is lack of evidence on whether it is beneficial to reinforce the cervix with cerclage when the cervical length becomes progressively shortened <10 mm while on vaginal progesterone.

OBJECTIVE

Our aims are to determine whether cerclage with vaginal progesterone will: (1) reduce the overall spontaneous preterm birth rate, (2) prolong pregnancy latency, and (3) improve neonatal outcomes compared to vaginal progesterone alone.

STUDY DESIGN

This was a retrospective cohort study at the University of Illinois at Chicago of all women with singleton pregnancy on vaginal progesterone for incidental short cervix, cervical length <20 mm. Only those with progressive cervical length shortening <10 mm who delivered at the University of Illinois at Chicago from January 2013 through December 2016 were included. The decision to perform cerclage was based on individual physician preference. Demographic data; information on serial cervical length status; medical, obstetric, and social history; cerclage vs no cerclage; and neonatal outcomes were compared.

RESULTS

A total of 310 women with incidental short cervix on vaginal progesterone were identified, and of these, 75 had progressive shortening cervical length <10 mm and met inclusion criteria. Among the women with extremely shortened cervical length <10 mm, 36 women (48%) had cervical cerclage plus vaginal progesterone, and 39 women (52%) continued on vaginal progesterone alone. The baseline characteristics, mean cervical length (5.06 vs 5.52 mm), and mean gestational age at diagnosis of extreme short cervix (21.5 vs 21.3 weeks) were similar between women who received cerclage vs those who did not, respectively. The mean gestational age at delivery was significantly greater for those with cerclage (34 weeks and 3 days vs 27 weeks and 2 days; P < .001). The rate of spontaneous preterm birth at <37, 35, 32, 28, and 24 weeks were significantly lower in the cerclage group: 44.1% vs 84.2%, 38.2% vs 81.6%, 23.5% vs 78.9%, 14.7% vs 63.2%, and 11.8% vs 39.5%, respectively. The rate of spontaneous preterm birth <37 weeks remained significant after controlling for confounders (relative risk, 0.11; 95% confidence interval, 0.03-0.41; P < .001). The average pregnancy latency was 14 weeks in the cerclage combined with vaginal progesterone group compared to vaginal progesterone alone group. Neonatal intensive care unit admission and development of respiratory distress syndrome were significantly lower in the cerclage group compared to vaginal progesterone alone group: 13 (36.1%) vs 23 (65.7%) (relative risk, 0.55; 95% confidence interval, 0.34-0.90; P = .018) and 8 (22.2%) vs 17 (43.6%) (relative risk, 0.59; 95% confidence interval, 0.29-0.90; P = .027), respectively. Neonates of women with cerclage were also significantly less likely to develop necrotizing enterocolitis or experience neonatal death.

CONCLUSION

Our study showed that cerclage plus vaginal progesterone in women with extremely shortened cervix significantly decreased overall spontaneous preterm birth rates, prolonged pregnancy latency by 2-fold, and decreased the overall neonatal morbidity and mortality.

Clinical effect of emergency cervical cerclage and elective cervical cerclage on pregnancy outcome in the cervical-incompetent pregnant women

PURPOSE

To compare the clinical effect of emergency cervical cerclage and elective cervical cerclage on pregnancy outcome in the cervical-incompetent pregnant women.

METHODS

Literature was searched from the databases of Pubmed, Embase and Google scholar. The fixed or random effects model was used to calculate pooled risk ratios on the basis of heterogeneity. Meta-regression, sensitive analysis, subgroup analysis, and publication bias assessment were also conducted to confirm the results according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009.

RESULTS

The meta-analysis results showed that there were significant associations between cerclage operations and pregnancy outcomes in gestation age, birth weight, and PROM rate. Gestation age was significantly higher in women with elective cerclage than those with emergency cerclage, and birth weight was significantly higher in newborns for the elective group as compared with emergency group. The rate of PROM in elective group was lower than emergency group. However, there were no differences between the emergency cerclage group and the elective cerclage group regarding the rate of vaginal delivery.

CONCLUSIONS

This meta-analysis suggests that emergency cerclage has lower gestation age and birth weight than elective cerclage, and it increases the risk of PROM. Further well-designed studies are warranted to confirm these results.

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.

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.

The molecular basis for sonographic cervical shortening at term: identification of differentially expressed genes and the epithelial-mesenchymal transition as a function of cervical length

OBJECTIVE

The purpose of this study was to determine whether cervical shortening of a ripe cervix at term is associated with changes in the cervical transcriptome.

STUDY DESIGN

Sonographically measured cervical lengths and biopsy specimens were obtained from 19 women at term who were not in labor with a ripe cervix. Affymetrix HG-U133 Plus 2.0 arrays (Affymetrix Inc, Santa Clara, CA) were used. Gene expression was analyzed as a function of cervical length. Gene Ontology, pathway analyses, quantitative real-time reverse transcription-polymerase chain reaction, and immunohistochemistry were performed.

RESULTS

Cervical length shortening was associated with differential expression of 687 genes. Fifty-four biologic processes, 22 molecular functions, and 9 pathways were enriched. Quantitative real-time reverse transcription-polymerase chain reaction analysis confirmed differential expression of 13 genes. Bone morphogenetic protein-7, claudin-1, integrin beta-6, and endometrial progesterone-induced protein messenger RNA, and protein expressions were down-regulated with cervical shortening.

CONCLUSION

Sonographic cervical shortening in patients at term who are not in labor with a ripe cervix is associated with changes in the uterine cervix transcriptome. The epithelial-mesenchymal transition may participate in the mechanism of cervical shortening at term.

Prevention of preterm birth based on a short cervix: cerclage

In an attempt to prevent preterm birth, clinicians have recommended cerclage for women with shortened cervical length and other worrisome sonographic cervical features in the mid-trimester, although randomized trials have not supported this practice. Emerging data suggest that preterm birth is a complex and poorly understood syndrome comprising several anatomic and functional components. As a result, preventive efforts have been mostly empiric and generally ineffective. Plausibly, effective preterm birth therapies exist, but matching the effective treatment with the correct patient has been problematic. Mid-trimester cervical changes visualized with vaginal sonography likely represent a pathologic process of premature cervical ripening and not real mechanical disability which has been traditionally treated with suture support. Cerclage may effectively reduce preterm birth in carefully selected women who have experienced a prior early preterm birth and who have shortened mid-trimester cervical length.

Goals and strategies for prevention of preterm birth: an obstetric perspective

Complications of prematurity surpass congenital malformations as the leading cause of infant mortality in the United States. Since 1990, there has been a steady rise in preterm birth, alarming health professionals from all disciplines. This review from a prenatal perspective confirms those concerns and describes the risks and opportunities that may attend efforts to improve the health of fetuses, newborns, and infants. Fetal and live-born outcomes are included.

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.

Transvaginal sonographic measurement of cervical length to predict preterm birth in asymptomatic women at increased risk: a systematic review

OBJECTIVES

To estimate the ability of cervical length measured by transvaginal ultrasonography in asymptomatic high-risk women to predict spontaneous preterm birth.

METHODS

MEDLINE, PubMed, EMBASE and the Cochrane Library were searched for articles published in any language between January 1980 and July 2006, using the keywords 'transvaginal ultrasonography' or ('cervix' and ('ultrasound' or 'ultrasonography' or 'sonography')); and ('preterm' or 'premature') and ('delivery' or 'labour/labor' or 'birth'), identifying cohort studies evaluating transvaginal ultrasonographic cervical length measurement in predicting preterm birth in asymptomatic women who were considered at increased risk (because of a history of spontaneous preterm birth, uterine anomalies or excisional cervical procedures), with intact membranes and singleton gestations. The primary analysis included all studies meeting the inclusion criteria. Secondary analyses were also performed specifically for (1) women with a history of spontaneous preterm birth; (2) those who had undergone an excisional cervical procedure; and (3) those with uterine anomalies.

RESULTS

Fourteen of 322 articles identified (involving 2258 women) met the criteria for systematic review. Cervical length measured by transvaginal ultrasonography predicted spontaneous preterm birth. The shorter the cervical length cut-off the higher the positive likelihood ratio (LR). The most common cervical length cut-off was < 25 mm. Using this cut-off to predict spontaneous preterm birth at < 35 weeks, transvaginal ultrasonography at < 20 weeks' gestation revealed LR+ = 4.31 (95% CI, 3.08-6.01); at 20-24 weeks, LR+ = 2.78 (95% CI, 2.22-3.49); and at > 24 weeks, LR+ = 4.01 (95% CI, 2.53-6.34). In women with a history of spontaneous preterm birth (six studies involving 663 women) cervical length at < 20 weeks revealed LR+ = 11.30 (95% CI, 3.59-35.57) and at 20-24 weeks LR+ = 2.86 (95% CI, 2.12-3.87), but there were limited data on the use of cervical length of more than 24 weeks in this group (one study involving 42 women). In women who had had excisional cervical procedures, two studies presented data on cervical length (one at < 24 weeks and one at > 24 weeks), finding cervical length at < 24 weeks to be predictive of spontaneous preterm birth at < 35 weeks (LR+ = 2.91, 95% CI, 1.69-5.01). One study (of 64 women) evaluated cervical length in women with uterine anomalies, finding it predictive of spontaneous preterm birth at < 35 weeks (LR+ = 8.14, 95% CI, 3.12-21.25).

CONCLUSION

Cervical length measured by transvaginal ultrasonography in asymptomatic high-risk women predicts spontaneous preterm birth at < 35 weeks. Further research may be warranted to evaluate the use of transvaginal ultrasonography after 24 weeks' gestation in women with a history of spontaneous preterm birth, and in women with uterine anomalies.

Primary, secondary, and tertiary interventions to reduce the morbidity and mortality of preterm birth

Interventions to reduce the morbidity and mortality of preterm birth can be primary (directed to all women), secondary (aimed at eliminating or reducing existing risk), or tertiary (intended to improve outcomes for preterm infants). Most efforts so far have been tertiary interventions, such as regionalised care, and treatment with antenatal corticosteroids, tocolytic agents, and antibiotics. These measures have reduced perinatal morbidity and mortality, but the incidence of preterm birth is increasing. Advances in primary and secondary care, following strategies used for other complex health problems, such as cervical cancer, will be needed to prevent prematurity-related illness in infants and children.

Second-trimester loss and subsequent pregnancy outcomes: What is the real risk?

OBJECTIVE

This study was performed to determine whether second-trimester pregnancy loss was associated with an increased risk for spontaneous preterm birth or recurrent second-trimester loss in a subsequent pregnancy.

STUDY DESIGN

A retrospective cohort study was conducted. Patients with a second-trimester pregnancy loss (n = 38), a spontaneous preterm birth (n = 76), and a full term delivery (n = 76) were identified from 2002 to 2005 (index pregnancy). Computerized medical records were used to obtain demographic and obstetrical histories.

RESULTS

Frequencies of subsequent second-trimester loss were 27%, 3%, and 1% in the second-trimester loss, spontaneous preterm birth, and full-term delivery cohorts, respectively. Frequencies of subsequent spontaneous preterm birth were 33%, 39.5%, and 9% in the same 3 cohorts. Patients with a prior second-trimester loss were 10.8 times more likely to have recurrent second-trimester loss or spontaneous preterm birth, compared with those with prior full-term delivery (confidence interval 3.6 to 32.1, P < .0001).

CONCLUSION

Patients with a prior second-trimester loss are at significantly increased risk for spontaneous preterm birth and recurrent second-trimester loss in their next pregnancy.

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.

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).

Could a cervical occlusion suture be effective at improving perinatal outcome?

Cervical weakness and infection have long been regarded as major causes of preterm birth. Cervical cerclage has been used extensively to reduce the risk of preterm birth arising as a result of cervical weakness, but increasing evidence suggests that the cervix plays more than just a mechanical role. Immunological function of the cervix and mucus plug is thought to be important in minimising the ingress of microbes, which can lead to chorioamnionitis and rupture of the amniotic membranes. In this review, we examine the background of traditional cervical cerclage and introduce the concept of the occlusion suture and its potential benefit in reducing the risk of recurrent preterm prelabour rupture of membranes.

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.

[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.

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.

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.

Role of ultrasound in screening patients at risk for preterm delivery

The ultrasound assessment of the cervix has contributed to the understanding of the pathways to preterm birth. Transvaginal ultrasound measurement of the cervix provides an objective and noninvasive tool for the evaluation of cervical status. Despite widespread use of this procedure, standardization of measurement indications, technique, and interval between examinations has not been achieved. The American College of Radiology has recently recommended that the cervix and lower uterine segment be imaged as part of every obstetric ultra-sound examination in the second trimester. These guidelines specifically suggest a search for a short cervix (less than 30 mm) or funneling. The expert panel on women's imaging further recommended evaluating the cervix sonographically on both the initial examination and all follow-up examinations for twin gestations. The American Institute of Ultrasound in Medicine guidelines indicate that evaluation of the uterus, including cervix, should be performed, but does not indicate specifically that the cervix should be measured. In contrast, the American College of Obstetricians and Gynecologists, although recognizing that cervical length assessment may be helpful in predicting the risk of preterm delivery (particularly from a negative predictive value), does not recommend routine use of cervical length measurement because of the lack of proved treatment or intervention methods. A review of the literature suggests that at the time of this writing the role of routine screening of low-risk women with cervical length assessment by ultrasound is not supported. In contrast, in women at risk for preterm delivery(eg, women with a prior history of preterm birth or women with multiple gestations) cervical length assessment may be useful for its negative predictive value. At present, however, there is no therapeutic intervention that has been proved to decrease the risk of preterm delivery in women with a documented cervix on ultrasound.

Cervical incompetence prevention randomized cerclage trial: Emergency cerclage with bed rest versus bed rest alone

OBJECTIVE

The purpose of this study was to compare preterm delivery rates and neonatal morbidity/mortality rates for women with cervical incompetence with membranes at or beyond a dilated external cervical os that was treated with emergency cerclage, bed rest plus indomethacin, versus just bed rest.

STUDY DESIGN

Women with cervical incompetence with membranes at or beyond a dilated external cervical os, before 27 weeks of gestation, were treated with antibiotics and bed rest and randomly assigned for emergency cerclage and indomethacin or bed rest only.

RESULTS

Twenty-three women were included; 13 women were allocated randomly to the emergency cerclage and indomethacin group, and 10 women were allocated randomly to the bed rest-only group. Gestational age at time of randomization was 22.2 weeks in the emergency cerclage and indomethacin group and 23.0 weeks in the bed rest-only group. Mean interval from randomization until delivery was 54 days in the emergency cerclage and indomethacin group and 20 days in the bed rest-only group (P=.046). Mean gestational age at delivery was 29.9 weeks in the emergency cerclage and indomethacin group and 25.9 weeks in the bed rest-only group. Preterm delivery before 34 weeks of gestation was significantly lower in the emergency cerclage and indomethacin group, with 7 of 13 deliveries versus all 10 deliveries in the bed rest-only group (P=.02).

CONCLUSIONS

Emergency cerclage, indomethacin, antibiotics, and bed rest reduce preterm delivery before 34 weeks compared with bed rest and antibiotics alone.

Changing trends in the obstetric indications for cervical cerclage

Cervical incompetence causes repeated mid-trimester miscarriage and preterm delivery with high fetal wastage. Since the introduction of cervical cerclage in 1951, it has undergone many changes with regard to the techniques, indications and postoperative care. The objective of this study is to review the changing trends in the current indications of cervical cerclage and subsequent perinatal outcome at the maternity hospital from January 1992 to December 1999. All the files of women who had had cervical cerclage were evaluated in terms of characteristics of the women, indications and obstetric outcome after cervical cerclage. Of 65539 who delivered in the hospital, 1021 women had had cervical cerclage, giving an incidence of 1.21%. There was a significant increase in the incidence of cervical cerclage, from 1.13% in 1992 to 1.40% in 1999 (P < 0.01). More women with multiple pregnancy in 1996 - 99 had cerclage than in 1992 - 94 period [22.7 vs. 8.5% (P < 0.01)]. It is clear that more cervical sutures are being performed in multiple pregnancies arising from assisted reproductive technology as well as after ultrasonographic evidence of cervical dilatation. A multicentre randomised clinical trial is therefore advocated to evaluate its effectiveness in these cases.