The risk of unexplained antepartum stillbirth in second pregnancies following caesarean section in the first pregnancy
Bibliographic record
Abstract
OBJECTIVE: To determine if a previous caesarean section increases the risk of unexplained antepartum stillbirth in second pregnancies. STUDY DESIGN: Retrospective cohort study. SETTING: Large Canadian perinatal database. POPULATION: 158 502 second births. METHODS: Data were obtained from a large perinatal database, which supplied data on demographics, pregnancy complications, maternal medical conditions, previous caesarean section and pregnancy outcomes. MAIN OUTCOME MEASURES: Total and unexplained stillbirth. RESULTS: The antepartum stillbirth rate was 3.0/1000 in the previous caesarean section group compared with 2.7/1000 in the previous vaginal delivery group (P= 0.46). Multivariate logistic regression modelling, including terms for maternal age (polynomial), weight >91 kg, smoking during pregnancy, pre-pregnancy hypertension and diabetes, did not document an association between previous caesarean section and unexplained antepartum stillbirth (OR 1.27, 95% CI 0.92-1.77). CONCLUSION: Caesarean section in the first birth does not increase the risk of unexplained antepartum stillbirth in second pregnancies.
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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 | 0.001 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".