OP19.02: The use of transvaginal ultrasonography to predict preterm birth in asymptomatic women at increased risk: a systematic review
Bibliographic record
Abstract
To estimate the accuracy of transvaginal ultrasound (TVUS) assessment of cervical length (CL) in predicting spontaneous preterm birth (SPTB) in asymptomatic high-risk women. MEDLINE, PubMed, EMBASE and the Cochrane Library were searched for human studies published in any language from Jan 1980 through July 2006, using the keywords ‘transvaginal ultrasound’ or ‘cervix’ and ‘ultrasound’; and ‘preterm delivery’ or ‘preterm birth’, identifying cohort studies evaluating TVUS CL in predicting PTB in asymptomatic women who were considered at increased risk(such as history of SPTB, uterine anomalies or cervical surgery), with intact membranes and singleton gestation. The primary outcome was SPTB < 35 weeks, with secondary outcomes of SPTB < 37, 32, 30, and 28 weeks, using a variety of CL cut-offs and gestational ages at TVUS (14–20 weeks, 20+ to 24 weeks, > 24 weeks). Fourteen of 322 studies found (2258 women) met the criteria for systematic review. TVUS CL predicted SPTB. The shorter the CL cut-off the higher the LR. The most common CL cut-off was < 25 mm. Using this cut-off to predict SPTB < 35 weeks, TVUS < 20 weeks revealed LR = 4.31 (95%CI, 3.08, 6.01); 20 to 24 weeks LR = 2.78 (95%CI, 2.22, 3.49); and > 24 weeks LR = 4.01 (95%CI, 2.53, 6.34). In women specifically with a history of SPTB (six studies, 663 women) TVUS < 20 weeks revealed LR = 11.30 (95%CI, 3.59, 35.57) and 20 to 24 weeks LR = 2.86 (95%CI, 2.12, 3.87), but there were limited data on the use of TVUS > 24 weeks in this group (one study, 42 women). One study (64 women) evaluated CL in women with uterine anomalies, finding it predictive of SPTB < 35 weeks (LR = 8.14, 95% CI, 3.12, 21.25). TVUS CL in asymptomatic high-risk women with singleton gestations predicts SPTB < 35 weeks. In women with a history of SPTB, TVUS predicts recurrent SPTB, but there is limited information on the use of TVUS in this group of women > 24 weeks, and in women with a history of uterine anomalies; therefore further research is needed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.009 | 0.040 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.016 | 0.011 |
| Bibliometrics | 0.014 | 0.013 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.008 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".