A Systematic Review and Meta-Analysis of the Association between the FV H1299R Variant and the Risk of Recurrent Pregnancy Loss
Bibliographic record
Abstract
This study evaluated the association between the H1299R factor V (FV) variant (rs1800595) and recurrent pregnancy loss (RPL). Pubmed (MEDLINE) and Embase (OVID) bibliographic databases were searched from the inception to 31 May 2022 to identify suitable articles according to PRISMA and MOOSE guidelines. We included observational studies, case-control studies, cross-sectional studies, and cohort studies reporting a numerical and well-distinguished Het or Hom status of the H1299R variant obtained through PCR or other biochemical techniques and comparing RPL patients with a healthy control group. The review protocol was registered at PROSPERO (CRD42022330077). Two authors independently screened studies, extracted data, and carried out the risk of bias assessment using the Newcastle Ottawa scale (NOS). A meta-analysis was performed with RevMan software Version 5.4 using an odds ratio (OR) with an M-H, random effect, and 95% CI. We included 13 clinical studies for a total of 1669 RPL patients and 1466 healthy women as a control group. H1299R variant was slightly associated with RPL albeit without significance (OR 1.18, 95% CI: 0.78–1.80, p = 0.44). Subgroup analyses considering H1299R in heterozygosity (OR 1.13, 95% CI: 0.76–1.67, p = 0.56) and in homozygosity (OR: 2.11, 95% CI: 0.74–6.01, p = 0.16) revealed a similar trend. Lastly, we evaluated the association between H1299R and RPL based on the number of previous miscarriages (≥2 or ≥3). This comprehensive systematic review and meta-analysis sheds light on the specific influence of the H1299R variant in the F5 gene on RPL, constituting valid support for medical care during pregnancy and genetic counseling.
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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 | 0.013 | 0.032 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.022 | 0.030 |
| Bibliometrics | 0.009 | 0.009 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 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".