In a twin pregnancy with a short cervical length ≤15 mm before 24 weeks and a prior history of pre‑term delivery or second‑trimester loss, is cervical cerclage indicated?

Cervical Cerclage in Twin Pregnancy with Short Cervix and Prior Preterm Birth

Cervical cerclage is NOT indicated for twin pregnancies with a short cervix ≤15 mm before 24 weeks, even with a prior history of preterm delivery or second-trimester loss, unless there is documented cervical dilation ≥1 cm. 1

Primary Guideline Recommendation

• The Society for Maternal-Fetal Medicine explicitly advises against routine use of cervical cerclage for cervical shortening in twin pregnancies, issuing a GRADE 1B recommendation that applies to all cases including cervical length ≤25 mm before 24 weeks. 2, 1

• This recommendation holds even in the presence of a prior preterm birth or second-trimester loss—the evidence from singleton pregnancies showing benefit of cerclage in high-risk patients does not translate to twin gestations. 1, 3

Evidence Base for This Recommendation

• An individual-patient-data meta-analysis of randomized trials demonstrated no benefit of cerclage in preventing preterm birth <34 weeks in twin gestations (adjusted OR 1.17,95% CI 0.23-3.79). 1, 4

• The same evidence base shows that routine ultrasound-indicated cerclage does not improve outcomes even when the cervix is very short (≤10 mm) in twins without dilation. 1

• Importantly, rates of very low birthweight and respiratory distress syndrome were significantly higher in the cerclage group compared to controls in randomized trials. 4

The Critical Exception: Cervical Dilation

Cerclage may be considered only when the cervix is ≤10 mm AND there is ≥1 cm of documented cervical dilation. 1

• A randomized trial (n ≈ 30) of twins meeting these specific criteria demonstrated a 70% reduction in preterm birth <34 weeks (70% vs 100%; RR 0.71,95% CI 0.52-0.96) with emergency cerclage. 1

• The benefit observed in this trial was attributed specifically to cervical dilation, not to cervical shortening alone—this is a fundamentally different pathophysiology. 1

• A recent 2025 trial comparing cerclage to pessary in twins with cervical length ≤28 mm showed cerclage was associated with significantly lower rates of delivery <28 weeks (1% vs 8.6%) and perinatal mortality (1% vs 5.8%), though the study was halted prematurely. 5

Management Algorithm for Your Specific Scenario

For Cervical Length ≤15 mm WITHOUT Dilation:

• Do not place cerclage—evidence shows no benefit and potential harm in this population. 1, 3, 4

• Perform serial transvaginal ultrasound every 1-2 weeks from 14-24 weeks to monitor for progression to dilation. 1

• Physical examination is essential when cervical length measures <15 mm, as 30-70% of patients will have cervical dilation ≥1 cm that may not be apparent on ultrasound alone. 6

• Consider vaginal progesterone 200 mg daily, though a recent meta-analysis showed no significant reduction in preterm birth <33 weeks in twins (RR 0.77,95% CI 0.48-1.25). 1

For Cervical Length ≤10 mm WITH Dilation ≥1 cm:

• Emergency cerclage can be offered after shared decision-making, provided there are no contraindications (active labor, chorioamnionitis, placental abruption, significant vaginal bleeding, or fetal anomalies incompatible with life). 1

• This represents the only evidence-based indication for cerclage in twin pregnancy. 1

Critical Pitfalls to Avoid

• Do not extrapolate singleton pregnancy benefits of cerclage to twin pregnancies—the pathophysiology of preterm birth in twins (uterine over-distension, increased inflammatory mediators) is not mitigated by mechanical cervical support. 1, 3

• Do not place cerclage based on prior obstetric history alone without objective cervical assessment showing both shortening AND dilation. 1, 6

• Do not use 17-alpha hydroxyprogesterone caproate (17-OHPC) for short cervix in twins—it has been shown ineffective with a GRADE 1B recommendation against its use. 2, 3, 6

• Do not place cervical pessary in twins—meta-analysis shows no consistent benefit and recent trials raised potential safety concerns including increased perinatal mortality. 2, 1, 3

Alternative Management Strategies

• Advise routine daily activities and light upper-body exercise, avoiding moderate-to-vigorous activity; do not prescribe bed rest, which offers no benefit and may be harmful. 1, 6

• Counsel patients on signs of preterm labor (uterine contractions, pelvic pressure, vaginal bleeding, fluid leakage) and signs of infection (fever, uterine tenderness, purulent discharge) requiring immediate evaluation. 1, 6

• Ensure transvaginal ultrasound using standardized technique (Perinatal Quality Foundation or Fetal Medicine Foundation protocols)—transabdominal measurement is insufficient for clinical decision-making. 1, 3

Why Prior History Doesn't Change the Recommendation in Twins

• Twin pregnancies have higher intrinsic rates of preterm birth due to fundamentally different mechanisms than singleton cervical insufficiency. 1

• The 2012 SMFM guideline explicitly states no evidence of effectiveness for any progestogen in preventing preterm birth in multiple gestations, regardless of risk factors. 1

• Cerclage in twins has not been adequately researched in women with previous preterm birth, and current evidence suggests it should not be used on the basis of short cervix alone even in this high-risk population. 7