What is Cerclage and Why It Is Used
Cervical cerclage is a medical procedure in which a stitch is placed around the cervix to help keep it closed during pregnancy. It is typically offered when there is a history of prior preterm birth or pregnancy loss linked to cervical insufficiency, and physical findings suggest an early shortening or opening of the cervix. The goal is to provide mechanical support, delay preterm birth, and improve the chances of reaching a safer gestational age for delivery. This overview explains who may be considered, the common approaches, what to expect during and after the procedure, and the evidence on effectiveness and risks.
How Cervical Insufficiency Leads to the Need for Cerclage
Cervical insufficiency, sometimes called an incompetent cervix, is a condition in which the cervix begins to dilate and efface too early in pregnancy without contractions or labor, increasing the risk of second-trimester loss or extreme preterm birth. This pattern may be identified from prior obstetric history or through ultrasound monitoring. Cerclage is considered when the cervix is shortening or opening in the setting of a prior poor obstetric outcome, aiming to prevent or significantly delay this process. By reinforcing the cervix, the procedure seeks to reduce the immediate risk of preterm delivery that can lead to neonatal complications.
Anatomy and Physiology of Cervical Function in Pregnancy
The cervix acts as a gatekeeper, remaining firm and closed while supporting the growing uterus and pregnancy. With hormonal changes and increasing uterine size, normal cervical remodeling occurs near term, but in cervical insufficiency this remodeling happens prematurely. Cerclage counteracts these changes by encircling the cervix with suture material, increasing resistance to dilation. The procedure is typically planned when objective measures, such as ultrasound or physical exam, show progressive shortening or funneling of the internal cervical os in a woman with a relevant history.
Key Clinical Indications and Candidacy for Cerclage
Candidates for cerclage generally have evidence of cervical insufficiency combined with a history that suggests a causal link between cervical changes and poor pregnancy outcomes. Selection is individualized and includes assessment of current cervical anatomy, gestational age at assessment, and the stability of the pregnancy. Reasons to proceed often include a prior spontaneous preterm birth attributed to cervical insufficiency with a short cervix in the current pregnancy, or a second-trimester loss with a pattern of painless cervical change. Important considerations also include infection screening, the absence of active labor or rupture of membranes, and confirmation of a live pregnancy with a reassuring fetus when feasible.
Historical Definitions and Evolving Criteria
Over time, clinical guidelines have refined who should be offered cerclage, shifting from rigid historic criteria to a more nuanced approach that incorporates ultrasound findings and risk history. Major professional organizations emphasize the importance of individualized decision-making, shared decision-making, and counseling about both potential benefits and limitations. Because evidence is strongest in specific high-risk situations, many pregnancies with a short cervix but without prior obstetric indications for cerclage are managed with progesterone or close monitoring instead.
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Primary Indication | Prior spontaneous preterm birth due to cervical insufficiency plus short cervix in current pregnancy | Guideline summary |
| Additional Indication | History of second-trimester loss with painless cervical dilation | Guideline summary |
| Contraindications | Active preterm labor, rupture of membranes, chorioamnionitis, lethal fetal anomaly | Guideline summary |
| Typical Timing of Placement | Usually between 12 and 14 weeks, based on history and monitoring | Guideline summary |
| Mode of Delivery Consideration | Often planned cesarean, but vaginal delivery may be possible depending on circumstances | Guideline summary |
Types of Cerclage Procedures and Technique
Several approaches exist for placing a cerclage, and the choice depends on clinical context, provider experience, and patient factors. Historically, a McDonald cerclage, which involves a single loop of suture placed at the vaginal portion of the cervix, has been common for indicated or prophylactic cases in selected patients. Another approach, the Shirodkar cerclage, uses a tape-like suture that is placed higher in the cervical canal and may be less likely to loosen, though it is typically performed through an abdominal or transvaginal approach with more extensive dissection. Transabdominal cerclage is generally reserved for specific anatomic or prior failed cases, as it involves placing a suture through the abdominal wall and cervix and is not commonly used in typical indications. Each technique aims to provide a secure but adjustable constriction around the cervix without causing significant trauma to surrounding tissues.
Transvaginal (McDonald and Shirodkar) Approaches
Transvaginal cerclage is most common in contemporary practice for women with a prior indicated preterm birth and a short cervix identified in the current pregnancy. A purse-string suture is placed around the cervix usually under ultrasound guidance, sometimes with local anesthesia, intravenous sedation, or regional anesthesia, depending on patient comfort and clinical context. The procedure is typically performed in an outpatient or brief inpatient setting, often during the second trimester window when the risk of preterm birth rises but the cervix remains accessible. Post-procedure monitoring may include observation for contractions, infection signs, and suture integrity, with plans for timing of removal close to term.
Transabdominal Cerclage in Select Cases
Transabdominal cerclage is considered in highly selected situations, such as women with a history of failed transvaginal cerclage, complex uterine anomalies, or cervical anatomic disruption. This approach requires abdominal surgery to tunnel a suture material through the cervix and surrounding tissues, often with a synthetic band. Because it is more invasive, it carries higher surgical risks, but it can provide durable support in circumstances where vaginal options are not suitable. Timing is typically earlier in pregnancy, and subsequent delivery is commonly by cesarean to avoid obstructed labor or suture complications.
Benefits, Risks, and Practical Considerations
For eligible individuals, cerclage can meaningfully delay preterm birth and extend the pregnancy closer to term, providing time for antenatal corticosteroids when indicated and reducing neonatal complications associated with extreme prematurity. However, the procedure is not without risks, which must be carefully weighed. Potential complications include bleeding, infection, rupture of membranes, preterm contractions, suture displacement or failure, and procedural challenges that may necessitate conversion to a different approach. Ongoing monitoring with serial cervical length assessment and clinical evaluation helps identify issues early and informs decisions about continuing the pregnancy or timing of delivery.
- Key benefits potentially include reduced preterm birth before a critical gestational threshold and improved neonatal outcomes when delivery is delayed.
- Known procedural risks encompass infection, bleeding, and rare events such as sline displacement or traumatic insertion.
- Important limitations include the need for close follow-up, possible suture adjustment or removal, and the fact that benefits are most clear in well-defined high-risk groups.
Post-Procedure Management and Long-Term Outcomes
Following cerclage placement, care typically involves activity modification, guidance on signs of complications, and scheduled visits to assess cervical length and fetal well-being. Cervical length monitoring by ultrasound, often between one and two weeks after the procedure and then periodically, can help detect changes that may require intervention. Timing of cerclage removal is planned with the goal of balancing continued support against the risk of obstructed labor, commonly near term or when no longer needed for cervical support. Delivery planning considers factors such as suture type, gestational age at removal, and any ongoing concerns, with cesarean delivery often chosen when feasible to avoid potential complications at the time of labor. Long-term outcomes for subsequent pregnancies are generally favorable when indicated, but individualized counseling remains essential to align expectations and management strategies.
Summary of Key Points
Cerclage is a procedure that places a suture around the cervix to provide mechanical support in selected pregnancies at risk of preterm birth due to cervical insufficiency. It is generally considered when there is a history of preterm birth or second-trimester loss plausibly related to early cervical changes, combined with objective evidence of cervical shortening in the current pregnancy. The procedure can be performed transvaginally via approaches such as McDonald or Shirodkar, or transabdominally in complex cases, and its timing is individualized. Benefits include the potential to significantly delay preterm birth, while risks include bleeding, infection, and the possibility of suture-related issues. Careful patient selection, counseling, and ongoing monitoring are central to optimizing outcomes and determining the most appropriate management for each person.