Cervical cerclage for short cervix at 24 to 26 weeks of gestation: systematic review and meta-analysis of randomized controlled trials using individual patient-level data.

OBJECTIVE: This study aimed to determine whether cervical cerclage for a transvaginal ultrasound-detected short cervical length after 24 weeks of gestation in singleton pregnancies reduces the risk for preterm birth. DATA SOURCES: Ovid MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials were searched using the following terms: "cerclage, cervical," "uterine cervical incompetence," "obstetrical surgical procedures," "cervix uteri," "randomized controlled trial," and "controlled clinical trial." STUDY ELIGIBILITY CRITERIA: All randomized controlled trials comparing cerclage placement with no cerclage in singleton gestations with a transvaginal ultrasound-detected short cervical length ≤25 mm between 24+0/7 and 29+6/7 weeks of gestation were eligible for inclusion. METHODS: Individual patient-level data from each trial were collected. If an eligible trial included patients with both multiple and singleton gestations with a short cervical length detected either before or after 24+0/7 weeks of gestation, only singletons who presented at or after 24+0/7 weeks were included. The primary outcome was preterm birth <37 weeks' gestation. Secondary outcomes included preterm birth <34, <32, and <28 weeks' gestation, gestational age at delivery, latency, preterm prelabor rupture of membranes, chorioamnionitis, and adverse neonatal outcomes. Individual patient-level data from each trial were analyzed using a 2-stage approach. Pooled relative risks or mean differences with 95% confidence intervals were calculated as appropriate. RESULTS: Data from the 4 eligible randomized controlled trials were included. A total of 131 singletons presented at 24+0/7 to 26+6/7 weeks of gestation and were further analyzed; there were no data on patients with a cerclage at 27+0/7 weeks' gestation or later. Of those included, 66 (50.4%) were in the cerclage group and 65 (49.6%) were in the no cerclage group. The rate of preterm birth <37 weeks' gestation was similar between patients who were randomized to the cerclage group and those who were randomized to the no cerclage group (27.3% vs 38.5%; relative risk, 0.78; 95% confidence interval, 0.37-1.28). Secondary outcomes including preterm birth <34, <32, and <28 weeks' gestation, gestational age at delivery, time interval from randomization to delivery, preterm prelabor rupture of membranes, and adverse neonatal outcomes such as low birthweight, very low birthweight, and perinatal death were similar between the 2 groups. Planned subgroup analyses revealed no statistically significant differences in the rate of preterm birth <37 weeks' gestation between the 2 groups when compared based on cervical length measurement (≤15 mm or ≤10 mm), gestational age at randomization (24+0/7 to 24+6/7 weeks or 25+0/7 to 26+6/7 weeks), or history of preterm birth. CONCLUSION: Cervical cerclage did not reduce or increase the rate of preterm birth among singleton pregnancies with a short cervical length detected after 24 weeks of gestation. Because there was a 22% nonsignificant decrease in preterm birth associated with cerclage, which is a similar amount of risk reduction often associated with ultrasound-indicated cerclage before 24 weeks' gestation, further randomized controlled trials in this patient population are warranted.

Cerclage for short cervix in twin pregnancies: systematic review and meta-analysis of randomized trials using individual patient-level data.

OBJECTIVE: To evaluate the efficacy of cerclage for preventing preterm birth in twin pregnancies with a short cervical length. DESIGN: We performed an individual patient data meta-analysis. Searches were performed in electronic databases. SETTING: Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, USA. POPULATION: Twin pregnancies in mothers with short cervical length. METHODS: We performed an individual patient data meta-analysis of randomized trials of twin pregnancies screened by transvaginal ultrasound in second trimester and where mothers had a short cervical length <25 mm before 24 weeks. Eligible women had to be randomized to cerclage vs. no-cerclage (control). MAIN OUTCOME MEASURES: The primary outcome was preterm birth <34 weeks. RESULTS: Three trials with 49 twin gestations with a short cervical length were identified. All original databases for each included trial were obtained from the primary authors. Risk factors were similar in the cerclage and control groups, except that previous preterm birth was more frequent and gestational age at randomization and delivery were earlier in the cerclage group compared with the control group. Adjusting for previous preterm birth and gestational age at randomization, there were no statistically significant differences in primary (adjusted odds ratio 1.17, 95% confidence interval 0.23-3.79) and secondary outcomes. Rates of very low birthweight and of respiratory distress syndrome were significantly higher in the cerclage group than in the control group. CONCLUSION: Based on these Level 1 data, cerclage cannot currently be recommended for clinical use in twin pregnancies with a maternal short cervical length in the second trimester. Large trials are still necessary.

Shirodkar versus McDonald cerclage for the prevention of preterm birth in women with short cervical length.

The efficacy of Shirodkar cerclage was compared with that of the McDonald procedure for the prevention of preterm birth (PTB) in women with a short cervix. Secondary analysis using data from all published randomized trials including women with a short cervical length (CL) was performed comparing the use of Shirodkar versus McDonald sutures. Analysis was limited to singletons with short CL on transvaginal ultrasound. The primary outcome measure was PTB < 33 weeks. Statistical analysis was performed using bivariate and multivariable techniques. From 607 women randomly assigned in the study, 277 met our inclusion criteria; 127 received Shirodkar and 150 women received McDonald sutures. The mean ( +/- standard deviation) gestational age at delivery was 35.0 +/- 5.3 versus 36.3 +/- 4.7 for the Shirodkar versus McDonald groups, respectively ( p< 0.02). PTB < 33 weeks was seen in 61 (22%) of 277 women; 26 (20%) of 127 in the Shirodkar and 35 (23%) of 150 in the McDonald groups, respectively (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.5 to 1.6). On adjusting for confounders using logistic regression modeling, no significant difference in PTB < 33 weeks was found between the two groups (OR, 0.55; 95% CI, 0.2 to 1.3). In women with short cervical length randomly assigned to receiving cerclage, no significant difference in prevention of PTB was observed using Shirodkar or McDonald's procedures.

Short cervix on ultrasound: does indomethacin prevent preterm birth?

OBJECTIVE: Our aim was to estimate if indomethacin therapy prevents preterm birth (PTB) in women with a short cervical length (CL) on transvaginal ultrasound (TVU). STUDY DESIGN: Individual-level data from all randomized trials including asymptomatic women with a short CL on TVU were analyzed for use of indomethacin at the time of the short CL. The trials eligible would be ones that randomized women with a short CL <25 mm, identified between 14 and 27 weeks. The eligible trials randomized such women to receive either cerclage or no cerclage. Only women who did NOT receive cerclage were analyzed. Exclusion criteria were major fetal anomaly and cerclage. We compared demographics, risk factors, and outcomes in women who, at the time of the short CL, received indomethacin or not. Primary outcome was PTB <35 weeks. RESULTS: Three of the 4 randomized trials identified had databases which recorded indomethacin use at the time of the short CL. A total of 139 women with a short CL <25 mm identified at 14 to 27 weeks were identified. Of these women, 99 (71.2%) received indomethacin, and 40 (28.8%) did not. Demographics and risk factors, including previous PTB (45.5% vs 62.5%; P = .11), were similar in the 2 groups. The primary outcome of PTB <35 weeks occurred in 29.3% (29/99) of women who received indomethacin, and 42.5% (17/40) of women who did not receive indomethacin (RR 0.69, 95% CI 0.44-1.13). PTB <24 weeks occurred in 1.0% (1/99) versus 7.5% (3/40), respectively (RR 0.14; 95% CI 0.02-0.92). Incidence of perinatal death was similar in the 2 groups (6% vs 10%; RR 0.61, 95% CI 0.19-1.95). CONCLUSION: Indomethacin therapy for asymptomatic women who have a short CL <25 mm on TVU at 14 to 27 weeks and do not receive a cerclage did not prevent spontaneous PTB <35 weeks, but did prevent PTB <24 weeks. Further research including larger numbers and a randomized trial design is necessary to further clarify the effectiveness as well as the risks of this therapy.

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.

Cerclage for short cervix on ultrasonography: meta-analysis of trials using individual patient-level data.

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.

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.

Modern management of preterm labour.

Preterm birth is the leading cause of neonatal morbidity and mortality. Cervical insufficiency is not an all or nothing phenomenon but a continuous variable which can lead to preterm deliveries at different gestational ages. The relationship between shortened cervical length and spontaneous preterm birth is consistent in several studies. Shortened cervical length can be diagnosed by transvaginal ultrasonography and treated by transvaginal cervical cerclage (TCC). A nomenclature to the different stages of prevention, as primary, secondary and tertiary was suggested to facilitate comparison of studies. Apart from cervical cerclage, the most widely used tocolytics are betamimetics. Although they have been shown to delay delivery, betamimetics have not been shown to improve perinatal outcome, and they have a high frequency of unpleasant and even fatal and maternal side effects. There is growing interest in calcium channel blockers which appear to be more effective than beta-sympathomimetic drugs and have few side-effects.

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.

Cervical incompetence: a reappraisal of an obstetric controversy.

UNLABELLED: Cervical incompetence is not a categoric but rather a continuous variable, meaning that there are various degrees in the competency of the cervix. Furthermore, a certain degree of competency of the cervix can be expressed differently in subsequent pregnancies. Women with risk factors for cervical incompetence in their gynecological/obstetric history should be followed by transvaginal ultrasonography. History alone is not an indication for a prophylactic cerclage. Although transvaginal ultrasonography identifies women at high risk of preterm delivery, it does not discriminate between different underlying pathologies. Short cervical length alone is not an indication for a therapeutic cerclage. Serial transvaginal ultrasonographic measurements of cervical length in women with risk factors can identify those women truly at high risk of preterm delivery. A transvaginal cervical cerclage with bed rest reduces preterm delivery and improves perinatal outcome in women with a short cervical length and risk factors for cervical incompetence. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader will be able to define cervical incompetence, explain the role of transvaginal ultrasonography in the prediction of preterm delivery, and summarize the data on the use of transvaginal cervical cerclage.