Shirodkar Cerclage at 22 Weeks’ Gestation

Published on 10/22/25

Clinical Implications of a Significant Cervical Length Change After a Shirodkar Cerclage at 22 Weeks’ Gestation

By Dr. Daniel Roshan

Introduction

Cervical insufficiency remains one of the challenging diagnoses in obstetrics, with significant implications for preterm birth risk and perinatal outcomes. For the busy obstetrician-gynecologist, understanding the evidence-based indications, procedural timing, and expected outcomes of cerclage placement is essential. In this blog, we will review a compelling case in which a transvaginal Shirodkar cerclage was placed at 22 weeks’ gestation, resulting in an increase in cervical length from 0.7 cm to 3.5 cm. We will then place this result in the context of current guidelines and clinical best practices.

Case Summary

At 22 weeks of pregnancy, the patient was diagnosed with cervical insufficiency (pre-cerclage cervical length: 0.7 cm). Following placement of a Shirodkar cerclage, the cervical length improved to 3.5 cm. This marked improvement underscores the potential anatomic benefit of cerclage in appropriately selected patients.

Pathophysiology & Rationale

The diagnosis of cervical insufficiency is often defined by the inability of the uterine cervix to maintain the pregnancy in the second trimester in the absence of labor or abruption. ACOG The cervix, under normal physiology, remains long, closed and firm until later in pregnancy when effacement and dilation proceed in a controlled fashion. NCBI In cervical insufficiency, a structural or functional defect—whether from prior cervical trauma, conization, cervical laceration, collagen disorders, or congenital anomaly—leads to premature shortening, dilatation or funneling. Medscape Because cervical length correlates inversely with preterm birth risk (particularly in women with prior preterm birth or second-trimester loss), monitoring cervical length and intervening when appropriate is a mainstay of management. Medscape

Cerclage – placing a suture around the cervix to reinforce it (whether via a McDonald or Shirodkar technique) – is an attempt to restore or maintain cervical integrity and prolong gestation. NCBI In this case, the suture appears to have produced an almost 5-fold increase in measurable cervical length (from 0.7 cm to 3.5 cm).

Why this case matters

Extremely short pre-cerclage cervical length: A cervical length of 0.7 cm (7 mm) is dramatic and places the patient at very high risk of preterm birth or mid-trimester pregnancy loss.
Post-cerclage length improvement: Achieving a length of 3.5 cm (35 mm) post-procedure suggests that the cerclage provided a meaningful structural effect, not just theoretical.
Timing: At 22 weeks gestation, the procedure falls into the “mid‐trimester” period where many guidelines would consider intervention if supported by history, exam or ultrasound findings.
Clinical implication: For practitioners, this offers encouragement that in selected patients with cervical insufficiency and dramatic shortening, cerclage may produce measurable cervical length improvement. While outcome data (gestational age at delivery, neonatal outcomes) would be desirable, the anatomical change alone may support the decision to intervene.

Guideline & Evidence-Based Considerations

To contextualize this case within best practices, we review the major guideline recommendations and relevant evidence.

Indications for cerclage (per major societies):

The American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin No. 142 states that cerclage is “reasonable” in women with (i) a history of second-trimester pregnancy loss related to painless cervical dilatation, (ii) prior cerclage for cervical insufficiency, or (iii) a history of spontaneous preterm birth (<34 weeks) and a short cervical length (<25 mm) before 24 weeks. PubMed
The Royal College of Obstetricians and Gynaecologists (RCOG) Green-top Guideline No. 75 similarly supports cerclage in women at risk of preterm birth/second trimester loss, but highlights that the optimal timing, technique and post‐operative management remain areas of debate. RCOG
The Society for Maternal‑Fetal Medicine (SMFM) summary (via OBGProject) outlines three major categories of cerclage: history-indicated, ultrasound-indicated, and physical examination (rescue) cerclage. The ObG Project

Key timing and measurement considerations:

For history-indicated cerclage (no shortening yet, but high-risk history), placement is often recommended at 12–14 weeks. The ObG Project
For ultrasound-indicated cerclage: in a singleton gestation with history of preterm birth and cervical shortening <25 mm before 24 weeks, cerclage may be considered. ACOG
For rescue (physical examination) cerclage: in singleton gestation, cervical dilatation (in absence of contractions/abruption/infection) before ~24 weeks may prompt consideration of cerclage. PubMed
The literature does not support cerclage for women with incidentally short cervix (<25 mm) who do not have a history of preterm birth or other risk factors. PubMed

Technique, monitoring & outcomes:

The two common transvaginal techniques are McDonald (purse-string around cervix) and Shirodkar (which involves bladder/dissection and suture placement at internal os). Both are acceptable; choice depends on surgeon’s experience and anatomical factors. NCBI
Post-cerclage cervical length measurement is not routinely recommended by ACOG as there is no evidence that repeated length measurement alters management. NCBI
Meta‐analyses indicate that in certain populations (e.g., exam-indicated cerclage) there is improved neonatal survival and prolonged gestation. The ObG Project
Complications of cerclage include infection, rupture of membranes, suture displacement. These risks should be weighed. NCBI

Application to this Case

In this specific scenario:

The patient’s cervical length (0.7 cm) was dramatically shortened, far below the commonly used threshold of 25 mm.
Although the earlier guideline-based thresholds (e.g., <25 mm before 24 weeks) are designed for ultrasound-indicated cerclage, this case arguably qualifies as a rescue/physical examination scenario given the extreme shortening.
The substantial increase to 3.5 cm after cerclage suggests a favorable anatomical response, which may correlate with prolongation of pregnancy and improved neonatal outcomes (though outcome data are not provided here).
From a best-practices perspective, key considerations are:
- Ensuring absence of active infection (subclinical chorioamnionitis) before cerclage placement. Medscape notes that in dilated cervix cases, amniocentesis to rule out intraamniotic infection may be considered. Medscape
- Ensuring correct indication (singleton gestation, absence of contractions or abruption) as per guideline.
- The observed anatomical change may provide confidence in the procedural efficacy; however, clinicians should remember that anatomical gain does not guarantee term delivery, but is a positive surrogate.

Clinical Take-Home Points for OBGYN Practice

Consider cerclage in patients with true cervical insufficiency (e.g., history of second-trimester loss, prior cerclage, or short cervix in setting of prior spontaneous preterm birth) — per ACOG & RCOG guidelines.
In cases of extreme cervical shortening (for example, <10 mm), cerclage placement may result in measurable structural improvement. While case data are limited, this may support the decision to intervene even beyond textbook thresholds.
Preoperative assessment is key: exclude active labor, rupture of membranes, infection; evaluate cervical length, and integrate history and ultrasound findings.
After cerclage placement, routine serial cervical length measurements may not change management and are not universally recommended; focus should instead be on overall obstetric monitoring.
Technical considerations: Choose a technique (McDonald vs Shirodkar) according to surgeon’s expertise and anatomical factors; ensure the patient is aware of risks (membrane rupture, infection, suture issues).
Post-procedure management should include standard obstetric surveillance and preterm birth prevention strategies (e.g., progesterone when indicated), while monitoring for potential complications.
Document the cervical length both before and after cerclage (as was done in this case) — this helps communicate the anatomical effect of the intervention and may assist in patient counselling.

Limitations & Considerations

While improved cervical length is encouraging, gestational age at delivery and neonatal outcomes remain the ultimate metric; this case report does not provide those endpoints.
The guidelines caution that cerclage in women without risk factors or in multiple gestations has not been shown to be beneficial and may even be harmful. ACOG+1
Even with anatomic improvement, patients remain at risk for preterm birth and should have ongoing surveillance and management.
Institutional experience, patient-counselling, and interdisciplinary care (maternal-fetal medicine involvement when appropriate) are vital.

Conclusion

This case highlights the practical value of cervical length measurement and timely surgical intervention in the context of cervical insufficiency. The noticeable increase in cervical length from 0.7 cm to 3.5 cm following a Shirodkar cerclage speaks to the potential of this intervention when appropriately applied. For obstetricians and gynecologists, this emphasises the importance of diligent risk identification, adherence to guideline-based indications, and careful perioperative management. While anatomical gain is a positive sign, it must be integrated into the broader obstetric plan to optimise outcomes for both mother and fetus.

References

Committee on Practice Bulletins—Obstetrics. “Cervical cerclage for the management of cervical insufficiency.” Obstet Gynecol. 2014;123(2 Pt 1):372–9. Lippincott Journals+2ACOG+2
Bieber KB, Olson SM. “Cervical Cerclage.” StatPearls. 2023. NCBI
Brown R, Gagnon R, Delisle MF. “Cervical insufficiency and cervical cerclage.” J Obstet Gynaecol Can. 2013;35(12):1115-1127. PubMed
RCOG Green-top Guideline No. 75: “Cervical cerclage (First edition).” RCOG
Ramus RM. “Cervical Insufficiency: Treatment & Management.” Medscape. Updated Oct 10 2024.

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