A randomized controlled trial of cervical cerclage in women at high risk of spontaneous preterm delivery. Revisiting the short cervix detected by transvaginal ultrasound in the second trimester: why cerclage therapy may not help. 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. Final results of the Cervical Incompetence Prevention Randomized Cerclage Trial (CIPRACT): therapeutic cerclage with bed rest versus bed rest alone. Cervical incompetence prevention randomized cerclage trial (CIPRACT): study design and preliminary results. Multicentred controlled trial of cervical cerclage in women at moderate risk of preterm delivery.
The effect of cervical suture on pregnancy outcome was studied in 194 women with a high risk (approximately 30%) of having a late abortion or a preterm delivery. The women were randomly allocated either to have a cervical suture inserted (n = 96) or to be managed without a suture (n = 98). There was no evidence that cervical cerclage either prolonged gestation or improved survival. Patients allocated to receive cerclage spent significantly longer in hospital, even when the period of admission for insertion was excluded. The patients in the cerclage group were more likely to receive tocolytic drugs, and more of them experienced puerperal pyrexia, although these differences between the groups were not statistically significant. 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. 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. To compare preterm delivery rates (before 34 weeks of gestation) and neonatal morbidity and mortality in patients with risk factors or symptoms of cervical incompetence managed with therapeutic McDonald cerclage and bed rest versus bed rest alone.
                Cervical length was measured in patients with risk factors or symptoms of cervical incompetence. Risk factors for cervical incompetence included previous preterm delivery before 34 weeks of gestation that met clinical criteria for the diagnosis of cervical incompetence, previous preterm premature rupture of membranes before 32 weeks of gestation, history of cold knife conization, diethylstilbestrol exposure, and uterine anomaly. When a cervical length of <25 mm was measured before a gestational age of 27 weeks, a randomization for therapeutic cerclage and bed rest (cerclage group) or bed rest alone (bed rest group) was performed. The analysis is based on intention to treat.
                Of the 35 women who met the inclusion criteria, 19 were allocated randomly to the cerclage group and 16 to the bed rest group. Both groups were comparable for mean cervical length and mean gestational age at time of randomization, mean overall 20 mm and 21 weeks. Preterm delivery before 34 weeks was significantly more frequent in the bed rest group than in the cerclage group (7 of 16 vs none, respectively; P =.002). There was no statistically significant difference in neonatal survival between the groups (13 neonates survived in the bed rest group vs all in the cerclage group). The compound neonatal morbidity, defined as admission to the neonatal intensive care unit or neonatal death, was significantly higher in the bed rest group than in the cerclage group (8 of 16 vs 1 of 19, respectively; P =.005; RR = 9.5, 95% CI, 1.3-68.1).
                Therapeutic cerclage with bed rest reduces preterm delivery before 34 weeks of gestation and compound neonatal morbidity in women with risk factors and/or symptoms of cervical incompetence and a cervical length of <25 mm before 27 weeks of gestation. 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. A total of 506 women at moderate risk of preterm delivery were randomly allocated to either cervical cerclage or a control group. Significantly more women in the group allocated to cerclage were admitted to hospital for reasons other than the operation and more received oral tocolytic drugs. There were also more caesarean sections and more preterm deliveries in the women allocated to cerclage although the differences between the two groups were small and not statistically significant.
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.]