The Risk of Venous Thrombosis among Women with Thrombophilia and Oral Contraceptive Use: A Meta-Analysis
Bibliographic record
Abstract
Abstract Introduction: Several small studies have reported an increased risk of venous thrombosis (VT) with thrombophilic disorders that is compounded by the use of oral contraceptives (OCP). The objective of this meta-analysis was to summarize the risk of VT among women with thrombophilia and OCP use, and to assess the interaction between OCP use and thrombophilia. Methods: Data sources used included MEDLINE, EMBASE, CINAHL, and COCHRANE REVIEW databases (1950–2008), and reference lists of retrieved articles. We selected studies that assessed among reproductive-aged women with and without VT the prevalence of OCP use and thrombophilic disorders, including factor V Leiden (FVL), prothrombin (PT) G20210A, elevated procoagulant factor VIII, hyperhomocysteinemia, lupus anticoagulant, and deficiencies of proteins C, S and antithrombin III. VT was defined as objectively confirmed deep vein thrombosis, pulmonary embolism or cerebral vein thrombosis. Fifteen studies were included. Two independent reviewers extracted data on study characteristics, quality, risk factors, and outcomes. Odds ratios (ORs) were calculated for each study and pooled using the random effects model. Results: There was an increased risk of VT in women with OCP use (pooled OR 3.0, 95% confidence interval (CI) 2.0–4.5), women with any thrombophilic disorder (pooled OR 4.8, 95% CI 3.6–6.5), women with FVL (pooled OR 4.7, 95% CI 3.1–7.5), and women with PT G20210A (pooled OR 3.3, 95% CI 0.8, 13.1). OCP users with FVL had a 18-fold increased risk of VT compared to healthy OCP non-users (pooled OR 17.8, 95% CI 5.6–56.8) and OCP-using women with PT G20210A had a 12-fold increased risk (pooled OR 12.4, 96% CI 0.9– 166) compared to healthy OCP non-users. The association of OCP use and VT was of similar magnitude among women with FVL (pooled OR 3.2, 95% CI 1.3–7.7) and women without FVL (pooled OR 3.9, 95% CI 1.8 to 8.6). Significant heterogeneity (I2 >80%) was present among models for OCP use, PT G20210A, and OCP use among FVL-negative women. Conclusions: We have shown that OCP use, thrombophilia, and in particular FVL and PT G20210A are associated with an elevated risk of VT of similar magnitude. However, the combination of OCP use and thrombophilia further amplifies the risk of VT compared to when either of the risk factors are considered alone. Though heterogeneity was observed, our study suggests, and confirms previous reports of an interaction between OCP use and thrombophilia.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.012 | 0.028 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.017 | 0.056 |
| Bibliometrics | 0.006 | 0.006 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".