How should a pregnant woman with a history of second‑trimester loss or a short cervical length be prepared for cervical cerclage?

Preparation for Cervical Cerclage

For a pregnant woman with a history of second-trimester loss or short cervical length, preparation for cerclage depends on the specific indication: perform infection screening at the first obstetric visit, confirm cervical measurements by transvaginal ultrasound, and counsel the patient on activity restrictions and symptom monitoring. 1

Pre-Procedure Infection Screening

• Obtain urinalysis with culture and sensitivity plus vaginal cultures for bacterial vaginosis at the first prenatal visit. 2
• Treat any identified infections before cerclage placement. 2
• This screening is critical because infection can compromise cerclage success and increase preterm birth risk. 1

Confirm Indication and Timing by Clinical Category

History-Indicated Cerclage (Prophylactic)

• Reserve for women with ≥3 prior second-trimester losses or extreme premature deliveries without other identifiable causes. 1, 3
• Place at 12–14 weeks of gestation in these high-risk patients. 1, 2
• Do NOT place cerclage at arbitrary gestational ages without objective cervical assessment. 1

Ultrasound-Indicated Cerclage

• Begin serial transvaginal ultrasound assessment of cervical length at 14–16 weeks in women with 1–2 prior second-trimester losses or preterm births. 1
• Offer cerclage placement only if cervical length shortens to ≤25 mm before 24 weeks. 1, 3
• Cerclage shows particular benefit when cervical length is <10 mm, with decreased preterm birth at <35 weeks (39.5% vs 58.0%). 1, 3
• Do NOT place cerclage routinely for cervical length 10–25 mm in women without prior preterm birth history (GRADE 1B). 1, 4

Examination-Indicated Cerclage (Rescue)

• Consider when cervical dilation is detected on physical examination before 24 weeks, particularly when cervical length measures <11–15 mm on ultrasound. 1
• This is a high-risk scenario with 30–70% of patients having cervical dilation ≥1 cm. 1

Ultrasound Confirmation Requirements

• All cervical length measurements must be obtained by transvaginal ultrasound using standardized technique—transabdominal measurements are insufficient. 1, 4
• Transvaginal ultrasound is the reference standard for cervical assessment, superior to clinical examination alone. 1
• If ultrasound shows cervical length <11–15 mm, perform physical examination to assess for cervical dilation. 1

Patient Counseling on Activity and Restrictions

• Permit routine daily activities and light upper-body resistance exercise. 1
• Avoid moderate-to-vigorous physical activity both before and after cerclage placement. 1
• Do NOT prescribe bed rest—it offers no benefit and may be harmful. 1

Symptom Monitoring Education

• Instruct the patient to promptly report signs of preterm labor: uterine contractions, pelvic pressure, vaginal bleeding, or fluid leakage. 1
• Advise the patient to watch for infection indicators: fever, uterine tenderness, or purulent vaginal discharge, and seek immediate evaluation if these occur. 1

Adjunctive Progesterone Therapy

• Add vaginal progesterone 200 mg daily after cerclage placement, as one study showed reduced spontaneous preterm birth at <34 weeks (2.2% vs 18.4%) and <37 weeks (9.1% vs 29.7%). 1, 3
• For women with 1–2 prior second-trimester losses and cervical length ≤20 mm, prescribe vaginal progesterone 200 mg daily (GRADE 1A). 1
• Consider vaginal progesterone through shared decision-making if cervical length is 21–25 mm (GRADE 1B). 1
• Do NOT use 17-alpha hydroxyprogesterone caproate (17-OHPC) for short cervix treatment (GRADE 1B). 1, 4

Contraindications to Cerclage

• Do NOT place cerclage in women without prior preterm birth history who have cervical length 10–25 mm without cervical dilation (GRADE 1B). 1, 3
• Do NOT place cervical pessary due to conflicting trial data and recent safety signals, including increased perinatal mortality (GRADE 1B). 1, 4
• Avoid cerclage in multiple gestations even with a history of preterm birth or short cervical length. 2

Ultrasound Guidance During Placement

• The American College of Radiology recommends performing transvaginal ultrasound with real-time imaging guidance, especially in high-risk situations such as placenta previa. 1

Post-Cerclage Surveillance

• Serial ultrasound monitoring after cerclage is NOT routinely recommended because evidence does not show clinical benefit. 1, 3
• However, shorter cervical length below the cerclage and presence of funneling are linked to higher preterm birth risk. 1
• Continue monitoring cervical length through 24 weeks in high-risk women, as approximately 69% maintain cervical length >25 mm and do not require cerclage. 1

Management of PPROM with Cerclage

• In the event of preterm prelabor rupture of membranes (PPROM) with a cerclage present, either removal or leaving it in situ may be considered after shared decision-making discussion of risks and benefits. 1, 3

Critical Pitfalls to Avoid

• Do NOT place cerclage at arbitrary gestational ages without objective cervical assessment. 1
• Clinical cervical dilation assessment alone is insufficient—transvaginal ultrasound provides superior risk stratification. 1
• After conization procedures, use serial cervical length measurements to assess for incompetence rather than automatic cerclage placement. 1