Transabdominal cerclage (TAC) achieved an overall success rate of 93.6% for delivery beyond 32 weeks in a London cohort.
Prior trachelectomy was strongly associated with very preterm delivery before 32 weeks (p < 0.0001).
Short cervical length in the first and second trimesters was significantly linked to earlier delivery.
Among women with prior pregnancies using the same TAC, 80% achieved at least one term birth.
Study Design | Observational cohort study |
Setting | Tertiary-level London hospital |
Population | Women who underwent TAC between 2011 and 2024 (N=125 pregnancies) |
Primary Outcome | Delivery before 32 weeks of gestation |
Key Results | 8 of 125 (6.4%) delivered before 32 weeks. Prior trachelectomy and shorter cervical length in first and second trimesters were significantly associated with preterm delivery (p < 0.001). |
Limitations | Single-center, small number of events, unadjusted comparisons, retrospective data |
Why This Study Matters
Transabdominal cerclage (TAC) is a surgical option for women with cervical insufficiency who cannot benefit from a vaginal cerclage. It is often used after failed vaginal cerclage or in cases of anatomical loss (e.g., after trachelectomy). While TAC is known to be effective, there is limited evidence on which patients are most likely to still experience very preterm delivery despite the procedure. This study sought to identify clinical characteristics associated with delivery before 32 weeks after TAC, helping clinicians better counsel patients and individualize management.
How the Study Was Conducted
The investigators conducted an observational cohort study using data from the Preterm Clinical Network (PCN) Database at a tertiary hospital in London. Women who underwent TAC between 2011 and 2024 and provided consent for inclusion were enrolled. The study compared maternal demographics, preterm birth risk factors, operative details (laparoscopic or open approach, performed before or during pregnancy), and subsequent cervical length measurements between women who delivered before 32 weeks and those who delivered at or after 32 weeks. Statistical comparisons used Student's t-test for continuous variables and chi-squared tests for categorical variables. The main outcome was defined as delivery before 32 weeks of gestation.
What the Researchers Found
TABLE 2. Operative details and transvaginal scan findings.
Successful TAC | Unsuccessful TAC | p | |
|---|---|---|---|
n = 117 (%) | n = 8 (%) | ||
TAC Type a | |||
Open TAC | 46 (93.9) | 5 (100) | 0.416 |
Laparoscopic TAC | 3 (6.1) | 0 (0) | |
TAC Timing b | |||
In pregnancy | 1 (0.8) | 0 (0) | |
Pre‐pregnancy | 116 (92.8) | 8 (100) | |
Mean first trimester CL in mm (SD) | 33.8 (5) [n = 20] | 19.3 (7) [n = 4] | < 0.001 |
Mean second trimester CL in mm (SD) | 31.9 (9) [n = 108] | 18.8 (14) [n = 7] | < 0.001 |
Mean third trimester CL in mm (SD) | 34.1 (10) [n = 79] | 26 (3) [n = 2] | 0.260 |
Among 125 pregnancies following TAC, 8 (6.4%) resulted in delivery before 32 weeks, demonstrating a high overall success rate of 93.6% for avoiding very preterm delivery. Prior trachelectomy was strongly associated with preterm delivery (p < 0.0001). Cervical length was significantly shorter in the unsuccessful group: mean first-trimester cervical length was 19.3 mm versus 33.8 mm (p < 0.001), and mean second-trimester cervical length was 18.8 mm versus 31.9 mm (p < 0.001). Importantly, of 30 women who had prior pregnancies with the same TAC in place, 24 (80%) achieved at least one term birth and 4 (13.3%) had two or more term deliveries, suggesting that the effectiveness of TAC persists across successive pregnancies.
What the Findings May Mean
The results reinforce that TAC is a highly effective intervention for preventing very preterm birth in women with cervical insufficiency, with more than 9 out of 10 women carrying beyond 32 weeks. However, the study identifies two factors that increase the risk of treatment failure: a history of trachelectomy (cervical removal) and a short cervical length in early pregnancy. These factors may help clinicians stratify risk and consider additional surveillance or adjunctive therapies. The finding that many women achieve multiple term births with the same cerclage indwelling highlights the long-term utility of TAC and supports its placement in appropriately selected patients.
Strengths and Limitations
Strengths of the study include the use of a dedicated preterm birth registry and the focus on a specific, well-defined clinical question. However, the study has important limitations. It is a single-center, observational design with a small number of events (only 8 preterm deliveries before 32 weeks), which limits statistical power and precludes multivariable adjustment. The analyses were unadjusted, so residual confounding by other risk factors (e.g., prior preterm birth, multiple gestation) cannot be excluded. Additionally, the results may not be generalizable to other settings with different patient populations or surgical techniques.
Implications for Practice and Research
Clinicians can use these findings to inform patients about the high success rate of TAC, while also noting that women with prior trachelectomy or short cervical length remain at elevated risk. Future research should aim to validate these associations in larger, multi-center cohorts, and explore whether targeted interventions (e.g., progesterone, serial cervical length monitoring) can further reduce risk in these subgroups. Prospective studies with standardized protocols and longer follow-up would help refine patient selection and optimize outcomes.
Funding, Disclosures, and Registration
Funding source not reported in the abstract. The authors' disclosures and trial registration details were not provided in the available material.
References
van der Krogt L, Story L, Suff N, Shennan A. Clinical Characteristics Associated With Very Preterm Delivery Despite Transabdominal Cerclage: A Cohort Study. BJOG. 2026;133(8):1553-1560. PMID: 41699431.
