For a pregnant woman with cervical insufficiency (≥2 prior second‑trimester losses or cervical length <25 mm before 24 weeks), what are the indications, timing, technique, postoperative care, and alternatives for cervical cerclage?

Cervical Cerclage: Indications, Timing, and Management

Direct Answer

For pregnant women with ≥2 prior second-trimester losses, offer history-indicated cerclage at 12-14 weeks; for those with cervical length <25 mm before 24 weeks and prior preterm birth, offer ultrasound-indicated cerclage; add vaginal progesterone 200 mg daily after placement. 1, 2

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Indications for Cerclage

History-Indicated Cerclage (Prophylactic)

• Place cerclage at 12-14 weeks for women with ≥3 second-trimester pregnancy losses or extreme premature deliveries without other identifiable causes 1, 2
• Reserve this approach for classic features of cervical insufficiency: prior second-trimester loss with painless cervical dilation in the absence of labor, rupture of membranes, or placental abruption 2
• Critical pitfall: Do NOT place history-indicated cerclage after prior previable preterm premature rupture of membranes (PPROM), as one study showed increased odds of preterm birth 2

Ultrasound-Indicated Cerclage

• For women with 1-2 prior second-trimester losses or preterm births: start serial transvaginal ultrasound at 14-16 weeks and offer cerclage only if cervical length shortens to ≤25 mm before 24 weeks 1, 3
• Approximately 69% of high-risk women maintain cervical length >25 mm and do not require cerclage 1
• Cerclage shows particular benefit when cervical length is <10 mm, with decreased preterm birth at <35 weeks (39.5% vs 58.0%) 1, 2
• Transvaginal ultrasound is the reference standard—superior to clinical examination alone 1

Examination-Indicated Cerclage (Emergency/Rescue)

• Offer cerclage when cervical dilation is detected on physical examination before 24 weeks, particularly when cervical length measures <11-15 mm on ultrasound 1
• Note that 30-70% of patients with cervical length <11-15 mm will have cervical dilation ≥1 cm on examination 1
• Consider rescue cerclage on an individual basis when membranes are exposed through the cervical os, acknowledging high risk of infective morbidity 4

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When NOT to Place Cerclage

Do NOT place cerclage in the following situations:

• Women without prior preterm birth history who have cervical length 10-25 mm—meta-analysis shows no benefit 1, 2
• At arbitrary gestational ages without objective cervical assessment 1
• Based on clinical cervical dilation assessment alone without ultrasound confirmation 1
• After conization procedures without documented cervical shortening on serial measurements 1

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Timing of Placement

• History-indicated cerclage: 12-14 weeks gestation 1, 2
• Ultrasound-indicated cerclage: when cervical length ≤25 mm before 24 weeks (continue monitoring through 24 weeks) 1
• Examination-indicated cerclage: before 24 weeks when dilation detected 1

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Technique Considerations

• McDonald and Shirodkar techniques are the standard transvaginal approaches 3
• Transabdominal cerclage can be offered to women who have had a failed transvaginal cerclage (delivery before 28 weeks after a history-indicated or ultrasound-indicated cerclage) 4
• Perform transvaginal ultrasound with real-time imaging guidance, particularly in high-risk situations like placenta previa 5

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Postoperative Care and Adjunctive Therapy

Vaginal Progesterone

Add vaginal progesterone 200 mg daily after cerclage placement—this significantly reduces spontaneous preterm birth: 1, 2

• Preterm birth <34 weeks: 2.2% vs 18.4% without progesterone
• Preterm birth <37 weeks: 9.1% vs 29.7% without progesterone

Surveillance After Cerclage

• Serial ultrasound monitoring after cerclage is NOT routinely recommended due to insufficient evidence supporting clinical benefit, although shorter cervical length below cerclage and funneling associate with higher preterm birth rates 5, 1
• If assessment is performed, measure total length of closed cervix regardless of cerclage sutures, and if funneling is present, measure from the level of funneling to the cerclage sutures 5

Cerclage Removal

• Remove cerclage at 36-37 weeks in women anticipating vaginal delivery 4
• Management of PPROM with cerclage in place is controversial—it is reasonable to either remove the cerclage or leave it in situ after discussing risks and benefits 2

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Alternative Management Strategies

For Women with 1-2 Prior Second-Trimester Losses

First-line approach: Serial ultrasound surveillance starting at 14-16 weeks 1

If cervical length ≤20 mm before 24 weeks:

• Prescribe vaginal progesterone 200 mg daily (GRADE 1A recommendation) 1

If cervical length 21-25 mm:

• Offer vaginal progesterone through shared decision-making (GRADE 1B recommendation) 1

If cervix shortens to <10 mm despite progesterone:

• Consider ultrasound-indicated cerclage based on shared decision-making 1, 2

What NOT to Use

• Do NOT use 17-alpha hydroxyprogesterone caproate (17-OHPC) for short cervix treatment (GRADE 1B recommendation against) 1
• Do NOT place cervical pessary due to conflicting trial data and recent safety signals, including increased perinatal mortality (GRADE 1B recommendation against) 1

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Evidence Quality and Nuances

The strongest evidence comes from recent ACOG guidelines (2026) prioritizing ultrasound-indicated cerclage over prophylactic placement 1, 2. The Cochrane review (2017) showed cerclage reduces preterm birth before 34 weeks (RR 0.77,95% CI 0.66 to 0.89) and probably reduces perinatal death (RR 0.82,95% CI 0.65 to 1.04), though the confidence interval crosses the line of no effect 6. The addition of vaginal progesterone after cerclage represents an important advancement, with compelling retrospective data showing substantial benefit 1, 2.

The key paradigm shift is away from automatic prophylactic cerclage toward objective, ultrasound-guided decision-making with progesterone as first-line therapy for many patients 1.