EP16.13: Clinical risk factors for placenta accreta or placenta percreta: a case‐control study
Bibliographic record
Abstract
A previous Caesarean section (CS) performed before labour is a risk factor for both uterine scar defect and uterine rupture. We aimed to determine the association between previous CS and risk of placenta accreta. We performed a case-control study where each case of placenta accreta/percreta that required a postpartum hysterectomy was matched to controls who delivered after a previous CS in the week before each case. Univariate and stepwise multivariate logistic regression analyses were performed to report risk factors. We compared 64 cases that required hysterectomy to 192 controls. The most important factor related to risk of placenta accreta was number of previous CS (2 CS: odds ratio [OR]: 3.4; 95% confidence interval [CI]: 2.1-5.5; >2 CS: OR: 4.0; 95% CI: 2.4-6.9). In women with a single previous CS, two factors were significant: a previous elective CS before labour (OR: 2.9; 95% CI: 1.1-7.7; adjusted OR: 4.3; 95% CI: 1.24-14.6); and an inter-delivery interval of less than 18 months since the last CS (OR: 3.0; 95% CI: 1.40-6.7; adjusted OR: 4.0; 95% CI: 0.7-24.1). A second stage CS was not a risk factor (OR: 0.4; 95% CI: 0.1-2.9) for placenta accreta. The lack of data regarding the closure of the uterus prevents us from drawing solid conclusions. Our results suggest that the number of previous CS, a previous elective CS delivery before labour, and potentially a short inter-delivery interval after CS, are significant risk factors for future severe placenta accreta/percreta requiring postpartum hysterectomy.
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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 | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".