OC19.06: Prevalence of postpartum hemorrhage in patients on ASA 162mg/day for pre‐eclamspia prevention
Bibliographic record
Abstract
To assess the risk of postpartum hemorrhage (PPH) in patients on pre-eclampsia prophylactic ASA on the available recommended dose of 162mg/day. A retrospective observational study was conducted at The Ottawa Hospital from January 2020 to December 2022. We compared the incidence of PPH in patients on ASA 162mg/day started at any time before 16 weeks to controls not taking ASA. PPH was defined by use of any uterotonic agent other than the standard of care (oxytocin) and/or use of any intervention to control excessive bleeding (Bakri balloon, uterine artery ligation/embolization, hysterectomy). We used this as a surrogate for the definition of PPH as absolute blood loss estimation can be subjective. We analysed patients who had a vaginal delivery and Caesarean in 2 subgroups. We excluded patients with any risk factors for PPH, such as multiple gestation, therapeutic anticoagulation, fibroids, uterine anatomical anomalies, placenta previa, placenta accreta spectrum disorders, and hereditary coagulopathies. A multivariate logistic regression was performed to control for confounders such as fetal macrosomia, general anesthesia, multiparty, pre-eclampsia and chronic hypertension. N = 3855 patients (307 ASA vs 3548 control group) were compared. Overall, the prevalence of PPH was 66.4% in the ASA vs 61% in the control group (p = 0.058) Amongst patients who delivered vaginally, no differences were found for PPH between ASA and control (36.8% vs 44.5%, p = 0.09) and the difference was still not significant when adjusted. Similarly, no differences were found amongst patients who had a Caesarean (86.8% vs 85.6%, p = 0.65). Our results show the prevalence of PPH is not statistically different between patients taking 162mg/d of ASA and controls.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".