Cervical cerclage for prevention of preterm delivery in women with short cervix: randomised controlled trial. Cervical incompetence prevention randomized cerclage trial (CIPRACT): study design and preliminary results. A randomized controlled trial of cervical scanning vs history to determine cerclage in women at high risk of preterm birth (CIRCLE trial). Multicenter randomized trial of cerclage for preterm birth prevention in high-risk women with shortened midtrimester cervical length. Final report of the Medical Research Council/Royal College of Obstetricians and Gynaecologists multicentre randomised trial of cervical cerclage. MRC/RCOG Working Party on Cervical Cerclage. Revisiting the short cervix detected by transvaginal ultrasound in the second trimester: why cerclage therapy may not help.
Cervical cerclage has been widely used in the past 50 years to prevent early preterm birth and its associated neonatal mortality and morbidity. Results of randomised trials have not generally lent support to this practice, but this absence of benefit may be due to suboptimum patient selection, which was essentially based on obstetric history. A more effective way of identifying the high-risk group for early preterm delivery might be by transvaginal sonographic measurement of cervical length. We undertook a multicentre randomised controlled trial to investigate whether, in women with a short cervix identified by routine transvaginal scanning at 22-24 weeks' gestation, the insertion of a Shirodkar suture reduces early preterm delivery.
                Cervical length was measured in 47?123 women. The cervix was 15 mm or less in 470, and 253 (54%) of these women participated in the study and were randomised to cervical cerclage (127) or to expectant management (126). Primary outcome was the frequency of delivery before 33 completed weeks (231 days) of pregnancy.
                The proportion of preterm delivery before 33 weeks was similar in both groups, 22% (28 of 127) in the cerclage group versus 26% (33 of 126) in the control group (relative risk=0.84, 95% CI 0.54-1.31, p=0.44), with no significant differences in perinatal or maternal morbidity or mortality.
                The insertion of a Shirodkar suture in women with a short cervix does not substantially reduce the risk of early preterm delivery. Routine sonographic measurement of cervical length at 22-24 weeks identifies a group at high risk of early preterm birth. The objective of this study was to compare different management strategies for women at risk for cervical incompetence.
                In an ongoing randomized trial patients with a previous preterm delivery at <34 weeks' gestation who met clinical criteria for the diagnosis of cervical incompetence are allocated to receive a prophylactic cerclage (prophylactic cerclage group) or not (observational group) in a proportion of 1:2. Transvaginal ultrasonographic follow-up examination of the cervix is performed in both groups. When a patient of the latter group has a cervical length <25 mm at <27 weeks' gestation, a further random assignment of therapeutic cerclage or no cerclage is performed. The analysis is by intent to treat.
                Primary random assignment allocated 23 women to the prophylactic cerclage group and 44 to the observational group. Both groups were comparable with respect to obstetric history. No significant difference was found between the prophylactic cerclage group and the observational group in preterm delivery at <34 weeks' gestation (3/23 vs 6/44, respectively) and neonatal survival (21/23 vs 41/44, respectively). A cervical length <25 mm was found in 18 patients (41%) in the observational group at a mean gestational age of 19.1 +/- 2.9 weeks' gestation. Incidence of preterm delivery at <34 weeks' gestation was significantly higher in the group with short cervical length (6/18 vs 0/26; P =.003). Secondary random assignment of the 18 patients with short cervical length allocated 10 to undergo therapeutic cerclage. Preterm delivery at <34 weeks' gestation was significantly less frequent in the therapeutic cerclage group (1/10 vs 5/8).
                Transvaginal ultrasonographic serial follow-up examinations of the cervix in women at risk for cervical incompetence, with secondary intervention as indicated, appears to be a safe alternative to the traditional prophylactic cerclage. Transvaginal ultrasonographic follow-up examination of the cervix can save the majority of women from unnecessary intervention. Placement of a therapeutic cerclage may reduce the incidence of preterm delivery at <34 weeks' gestation among high-risk patients. We sought to compare history-indicated placement of cervical cerclage based on history- vs ultrasound-indicated placement in women at risk of preterm birth.
                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.
                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).
                Screening women at high risk with cervical ultrasound to determine cerclage placement results in more intervention but similar outcome compared with history-indicated placement. The objective of the study was to assess cerclage to prevent recurrent preterm birth in women with short cervix.
                Women with prior spontaneous preterm birth less than 34 weeks were screened for short cervix and randomly assigned to cerclage if cervical length was less than 25 mm.
                Of 1014 women screened, 302 were randomized; 42% of women not assigned and 32% of those assigned to cerclage delivered less than 35 weeks (P = .09). In planned analyses, birth less than 24 weeks (P = .03) and perinatal mortality (P = .046) were less frequent in the cerclage group. There was a significant interaction between cervical length and cerclage. Birth less than 35 weeks (P = .006) was reduced in the less than 15 mm stratum with a null effect in the 15-24 mm stratum.
                In women with a prior spontaneous preterm birth less than 34 weeks and cervical length less than 25 mm, cerclage reduced previable birth and perinatal mortality but did not prevent birth less than 35 weeks, unless cervical length was less than 15 mm. To assess whether cervical cerclage in women deemed to be at increased risk of cervical incompetence prolongs pregnancy and thereby improves fetal and neonatal outcome.
                Multicentre randomised controlled trial.
                Hospitals in the United Kingdom, France, Hungary, Norway, Italy, Belgium, Zimbabwe, South Africa, Iceland, Ireland, the Netherlands and Canada.
                One thousand two hundred and ninety-two pregnant women whose obstetricians were uncertain whether to recommend cervical cerclage, most of whom had a history of early delivery or cervical surgery.
                Cervical cerclage was compared with a policy of withholding the operation unless it was considered to be clearly indicated.
                Delivery before 33 completed weeks, preterm delivery (< 37 weeks), and vital status of the baby after completion of the pregnancy.
                The overall preterm delivery rate was 28%. There were fewer deliveries before 33 weeks in the cerclage group (83 (13%) compared with 110 (17%), P = 0.03) and this difference reflected deliveries characterised by features of cervical incompetence (painless cervical dilatation and prelabour rupture of the membranes). There was a corresponding difference in very low birthweight deliveries (63 (10%) compared with 86 (13%), P = 0.05). The difference in the overall rate of miscarriage, stillbirth or neonatal death (55 (9%) compared with 68 (11%)) was less marked and was not statistically significant. The use of cervical cerclage was associated with increased medical intervention and a doubling of the risk of puerperal pyrexia.
                These results suggest that the operation had an important beneficial effect in 1 in 25 cases in the trial (95% confidence interval (CI) 1 in 12 to 1 in 300 sutures). Its use is associated with increased medical intervention and puerperal pyrexia. Nevertheless, this trial suggests that, on balance, cervical cerclage should be offered to women at high risk, such as those with a history of three or more pregnancies ending before 37 weeks gestation. The purpose of this study was to identify the risk factors that are associated with increased neonatal morbidity in patients who were treated for sonographic evidence of internal os dilation and distal cervical shortening during the second trimester.
                From May 1998 to June 2000 patients between 16 and 24 weeks of gestation with the following sonographic criteria were randomly assigned to McDonald cerclage or no cerclage: internal os dilation and either membrane prolapse into the endocervical canal at least 25% of the total cervical length but not beyond the external os or a shortened distal cervix <2.5 cm. Before randomization, all patients were treated identically with an amniocentesis, multiple urogenital cultures, and therapy with indomethacin and clindamycin for 48 to 72 hours. Except for the cerclage, all patients were treated identically after randomization. Multiple variables of perinatal outcome were analyzed. A regression model with gestational age at delivery as the dependent variable was constructed and repeated with neonatal morbidity as the dependent variable. This model was applied to 3 populations: the cerclage group, the no cerclage group, and both groups combined.
                Of the 135 patients, 20 patients declined randomization, and 2 patients were diagnosed with acute chorioamnionitis. Of the 113 patients remaining, 55 patients were randomly assigned to the cerclage group, and 58 patients were randomly assigned to the no cerclage group. There were 8 rescue cerclage procedures (4 in each group). Regression analysis showed that readmission for preterm labor, chorioamnionitis, and abruption were consistently associated with early gestational age at delivery and increased morbidity. Cerclage did not affect perinatal outcome.
                The sonographic findings of second trimester internal os dilation, membrane prolapse, and distal cervical shortening likely represent a common pathway of several pathophysiologic processes. Use of cerclage does not alter any perinatal outcome variables. Increased neonatal morbidity in these patients appears to be associated with subclinical infection, preterm labor, and abruption.
The use of a cervical stitch should not be offered to women at low or medium risk of mid trimester loss, regardless of cervical length by ultrasound. The role of cervical cerclage for women who have short cervix on ultrasound remains uncertain as the numbers of randomised women are too few to draw firm conclusions.
There is no information available as to the effect of cervical cerclage or its alternatives on the family unit and long term outcome. 
[Note: The 23 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]