Identifying Clinical Factors Associated with Postpartum Hemorrhage in Women with Inherited Bleeding Disorders: A Population-based Cohort Study of Women in Ontario
Bibliographic record
Abstract
Background: Postpartum hemorrhage (PPH) is an obstetric emergency. Inherited bleeding disorders (IBD) can increase PPH risk, however the impact of other risk factors (including anemia, parity) on this association remains unclear. Women with IBD may be anemic due to increased bleeding tendencies; however, the pathways linking IBD, anemia and PPH have not been fully characterized. This thesis aimed to identify maternal, clinical, and delivery characteristics associated with PPH among women with, and without, IBDs. Objectives: 1) To determine and compare PPH incidence among women with and without IBDs; 2) to determine the effect of IBD on PPH; 3) to determine if anemia at admission for delivery mediates the relationship between an IBD and PPH. Methods: We conducted a retrospective cohort study using data housed within ICES (formerly: the Institute for Clinical and Evaluative Sciences). Women with an in-hospital, live or stillborn delivery between 2014-2019 were included. To address Objective 1, PPH incidence proportions were calculated. Objective 2 was addressed using block-analysis regression. Objective 3 was addressed using mediation analysis. Analysis was restricted to the first delivery in the accrual period and stratified by parity. Results: 601,773 women were included; 2,002 (0.33%) had an IBD. PPH incidence was 1.5x higher (7.30 vs. 4.93 cases/100 deliveries, std. difference 0.1) among women with an IBD compared to unaffected women. Women with IBDs were slightly older, and more frequently diagnosed with chronic hypertension, anemia, and prior PPH. Among the total cohort, an IBD was associated with increased risk of PPH (adjusted RR [aRR] = 1.26; 95% CI 1.08, 1.46). Among multiparous women, prior PPH was associated with increased PPH risk, while IBD had no effect (aRR = 1.10; 95% CI 0.86, 1.40). Anemia, placental conditions, multifetal gestation, and induction were associated with increased PPH risk among all cohorts. Despite significant associations between each of IBD, PPH and anemia at admission for delivery, the latter did not mediate the IBD-PPH relationship. Conclusions: Optimal maternal outcomes require identification of maternal risks. Study findings can be used to inform guideline development and healthcare provider education and will contribute to improved health and quality of life of women with bleeding disorders.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".