Cervical cerclage for prevention of preterm birth and adverse perinatal outcome in twin pregnancies with short cervical length or cervical dilatation: A systematic review and meta-analysis

Abstract

Background The optimal approach to prevent preterm birth (PTB) in twins has not been fully established yet. Recent evidence suggests that placement of cervical cerclage in twin pregnancies with short cervical length at ultrasound or cervical dilatation at physical examination might be associated with a reduced risk of PTB. However, such evidence is based mainly on small studies thus questioning the robustness of these findings. The aim of this systematic review was to determine the role of cervical cerclage in preventing PTB and adverse maternal or perinatal outcomes in twin pregnancies. Methods and findings Key databases searched and date of last search: MEDLINE, Embase, and CINAHL were searched electronically on 20 April 2023. Eligibility criteria: Inclusion criteria were observational studies assessing the risk of PTB among twin pregnancies undergoing cerclage versus no cerclage and randomized trials in which twin pregnancies were allocated to cerclage for the prevention of PTB or to a control group (e.g., placebo or treatment as usual). The primary outcome was PTB <34 weeks of gestation. The secondary outcomes were PTB <37, 32, 28, 24 weeks of gestation, gestational age at birth, the interval between diagnosis and birth, preterm prelabor rupture of the membranes (pPROM), chorioamnionitis, perinatal loss, and perinatal morbidity. Subgroup analyses according to the indication for cerclage (short cervical length or cervical dilatation) were also performed. Risk of bias assessment: The risk of bias of the included randomized controlled trials (RCTs) was assessed using the Revised Cochrane risk-of-bias tool for randomized trials, while that of the observational studies using the Newcastle–Ottawa scale (NOS). Statistical analysis: Summary risk ratios (RRs) of the likelihood of detecting each categorical outcome in exposed versus unexposed women, and (b) summary mean differences (MDs) between exposed and unexposed women (for each continuous outcome), with their 95% confidence intervals (CIs) were computed using head-to-head meta-analyses. Synthesis of the results: Eighteen studies (1,465 twin pregnancies) were included. Placement of cervical cerclage in women with a twin pregnancy with a short cervix at ultrasound or cervical dilatation at physical examination was associated with a reduced risk of PTB <34 weeks of gestation (RR: 0.73, 95% CI [0.59, 0.91], p = 0.005 corresponding to a 16% difference in the absolute risk, AR), <32 (RR: 0.69, 95% CI [0.57, 0.84], p < 0.001; AR: 16.92%), <28 (RR: 0.54, 95% [CI 0.43, 0.67], 0.001; AR: 18.29%), and <24 (RR: 0.48, 95% CI [0.23, 0.97], p = 0.04; AR: 15.57%) weeks of gestation and a prolonged gestational age at birth (MD: 2.32 weeks, 95% [CI 0.99, 3.66], p < 0.001). Cerclage in twin pregnancy with short cervical length or cervical dilatation was also associated with a reduced risk of perinatal loss (RR: 0.38, 95% CI [0.25, 0.60], p < 0.001; AR: 19.62%) and composite adverse outcome (RR: 0.69, 95% CI [0.53, 0.90], p = 0.007; AR: 11.75%). Cervical cerclage was associated with a reduced risk of PTB <34 weeks both in women with cervical length <15 mm (RR: 0.74, 95% CI [0.58, 0.95], p = 0.02; AR: 29.17%) and in those with cervical dilatation (RR: 0.68, 95% CI [0.57, 0.80], p < 0.001; AR: 35.02%). The association between cerclage and prevention of PTB and adverse perinatal outcomes was exclusively due to the inclusion of observational studies. The quality of retrieved evidence at GRADE assessment was low. Conclusions Emergency cerclage for cervical dilation or short cervical length <15 mm may be potentially associated with a reduction in PTB and improved perinatal outcomes. However, these findings are mainly based upon observational studies and require confirmation in large and adequately powered RCTs.

Desafios na prevenção do parto pré-termo associado à insuficiência cervical

“…Revisões sistemáticas e metanálises com objetivo de determinar o papel da cerclagem cervical em gestações gemelares concluíram que a cerclagem na presença de dilatação cervical (cerclagem de emergência) ou comprimento cervical <15 mm pode estar associada a uma redução do parto pré-termo e a melhores resultados maternos e perinatais 44,45 .…”

Study protocol for two randomised controlled trials evaluating the effects of Cerclage in the reduction of extreme preterm birth and perinatal mortality in twin pregnancies with a short cervix or dilatation: the TWIN Cerclage studies

“…In women with a twin pregnancy and asymptomatic cervical dilatation, the most recent systematic review was published in August 2023 and included one RCT and five retrospective cohort studies. 12 These studies showed that a vaginal cerclage may result in a reduction of PTB at less than 24 weeks (RR 0.32; 95% CI 0.21 to 0.48), 28 weeks (RR 0.47; 95% CI 0.36 to 0.62), 32 weeks (RR 0.59; 95% CI 0.50 to 0.70) and 34 weeks (RR 0.68; 95% CI 0.57 to 0.80). In addition, women with a cerclage had a reduced risk of perinatal death (RR 0.30; 95% CI 0.16 to 0.55), 5 min Apgar score of <7 (RR 0.49; 95% CI 0.27 to 0.90), birthweight of <1500 g (RR 0.41; 95% CI 0.31 to 0.55) and admission to the neonatal intensive care unit (NICU) (RR 0.67; 95% CI 0.52 to 0.88).…”

Role of cerclage in twin and singleton pregnancy: evidence from systematic review and meta‐analysis

“…Cervical cerclage has been classically contraindicated in twin pregnancy, but this evidence was based on small, underpowered randomized controlled trials 3,4 . More recently, randomized controlled trials and systematic reviews have reported a beneficial role of cervical cerclage in reducing the risk of PTB and improving perinatal outcome in asymptomatic twin pregnancies presenting with cervical dilatation or short CL on ultrasound 5 .…”