Tranexamic acid vs placebo for death due to bleeding in postpartum haemorrhage

Overview

Tranexamic acid vs placebo for death due to bleeding in postpartum haemorrhage

In women with a clinical diagnosis of postpartum haemorrhage, does tranexamic acid added to usual care reduce death due to bleeding versus placebo? (Double-blind placebo-controlled RCTs.)

Primary outcome

Transparency (independently checkable)

15 of 15 numerical claims on this page (100%) carry a one-click source a reader can open to check independently — each pooled number its PMID/NCT and verbatim span, each declared-absent trial its reason, each risk-of-bias domain the structured field it read, the reproduction its protocol SHA and replay result. The published comparator exposes 2 such claim(s) — its reported estimate(s) with one citation; its per-trial inputs are not machine-exposed. Score: scripts/transparency_score.py (committed docs/transparency.json).

Stated limitations

• Small k on many topics. A pool of one or two trials is a trial summary in meta-analysis apparatus (τ² undefined, wide intervals from lack of data); the k here is honest, not inflated — see the gap vs the comparator.
• Open-access comparator only. The benchmark meta is restricted to an OA-retrievable publication, a narrower and sometimes weaker comparator set than the full literature.
• Favourable topic sample. Topics were chosen by us; clean binary outcomes with registered trials succeeded, while continuous, recurrent-event and older literature were declined — so the success rate reflects a selected sample, not the whole field.
• Risk of bias is partial. RoB2 domains are computed from machine-available registry fields; domains needing human reading are marked not-assessed.
• Registry snapshot is dated. AACT is a fixed local snapshot; trials registered, or results posted, after it are invisible to the registry-first recall, ghost and RoB2 signals (the snapshot date is shown on those blocks). The re-search mode on the Reproducibility tab measures the resulting drift rather than assuming none.
• Dual screening is not fully independent. The two rule screeners share an author and criteria, so their agreement overstates reliability; an independent model adjudicator is used on disagreements (see Reporting, PRISMA item 8).
• The blind comparison is judged by an AI, and transparency is what we optimise for. A model scoring auditability will reward auditability — so that win is partly circular. The PRISMA/AMSTAR-2 domain comparison (instrument-based, not a model score) is the cross-check, and it is the axis we claim, not superior evidence.

Protocol

# Protocol - tranexamic acid for postpartum haemorrhage

**Registration.** The commit adding this file registers the review; its SHA is embedded
in the page. Committed before the synthesis runs.

## PICO
- **P** - women with a clinical diagnosis of postpartum haemorrhage after vaginal birth
  or caesarean section.
- **I** - tranexamic acid added to usual care.
- **C** - matching placebo added to usual care.
- **O (primary)** - death due to bleeding.
- **O (harms)** - thromboembolic events and adverse events.

## Estimand / population / timepoint
- **Estimand** - risk ratio (RR), tranexamic acid vs placebo.
- **Population** - intention-to-treat as randomised.
- **Timepoint** - in hospital.

## Eligibility - on P/I/C/DESIGN ONLY
Include a record iff all hold:
- **I1** - randomised controlled trial;
- **I2** - population is established postpartum haemorrhage, judged from the title or
  registry conditions;
- **I3** - tranexamic acid vs placebo, both added to usual care;
- **design** - double-blind, placebo-controlled.

Exclude (reason must be true of the record):
- **X1** - not an RCT (review, guideline, observational, protocol-only);
- **X2** - wrong population (e.g. prophylaxis/prevention at delivery before postpartum
  haemorrhage, placenta previa prophylaxis, trauma, gastrointestinal bleeding);
- **X3** - wrong intervention/comparison (no tranexamic-acid-vs-placebo contrast);
- **X-DESIGN** - not double-blind and placebo-controlled (e.g. open-label);
- **X5** - off-topic: a primary trial of another topic in this set (negative control).

Eligibility is NOT on the outcome axis. Whether a trial reports death due to bleeding,
or gives arm counts versus only an effect plus CI, is recorded as target-result status
at extraction and is never an exclusion. A published effect plus 95% CI is a poolable
input.

## Search (fetch-once; raw results committed under cache/<slug>/records.json; screening replays offline)
- PubMed: tranexamic acid x postpartum haemorrhage/hemorrhage x WOMAN/death/trial terms,
  plus oral treatment/placebo and TRACES sweeps for recall.
- ClinicalTrials.gov: condition "postpartum hemorrhage", intervention "tranexamic acid".

## Synthesis method (DECLARED = served)
Random-effects inverse-variance on log(RR); Paule-Mandel tau^2; HKSJ 95% CI on t_{k-1}
(floor max(1,Q/(k-1))); prediction interval mu +/- t_{k-1}*sqrt(tau^2+se^2).
DerSimonian-Laird forbidden. Engine validated vs metafor 5.0.1 (<1e-6).

## Comparator (resolved; open-access confirmed)
The 2024 Lancet individual-patient-data systematic review and meta-analysis
"Tranexamic acid for postpartum bleeding: a systematic review and individual patient
data meta-analysis of randomised controlled trials" (PMID 39461793, PMC12197804, DOI
10.1016/S0140-6736(24)02102-0; Unpaywall is_oa=true). It reports the comparator primary
effect for life-threatening postpartum bleeding as pooled OR 0.77 (95% CI 0.63-0.93)
and thromboembolic events as pooled OR 0.96 (95% CI 0.65-1.41).

## Controls
- **Positive** - the search must recover and include WOMAN (PMID 28456509), oral TXA
  adjunct treatment for PPH (PMID 32143721), and TRACES haemorrhagic caesarean dose
  ranging (PMID 36243576).
- **Negative** - HALT-IT (tranexamic acid for acute gastrointestinal bleeding, PMID
  32563378 - another disease area) must be recovered and EXCLUDED as the wrong
  population.

Search

Source status (which adapters ran)

Citation chase: NOT_RUN · ClinicalTrials.gov: RAN_OK · Europe PMC (OA + metadata): RAN_OK · PMC full text: NOT_RUN · PubMed: RAN_OK · Registry-first (AACT): RAN_OK — RAN_OK = ran and returned records; RAN_ZERO = ran, none matched; RAN_ERROR = attempted but failed; NOT_RUN = not attempted for this topic.

Registry-first recall (reach)

Registry-first RECALL: recovered 2/3 of this topic's known trials (enumerated 33; status RAN_OK). Reachable ceiling 3/3: 1 trial(s) are registered but not enumerated by the committed query (registry vocabulary limit — improvable). Missed: 36243576. Measured 2026-09-11T23:39:14Z. Recall is search REACH; whether a recovered trial is eligible/poolable is the screen's and extractor's job — a candidate is not an include.

Registry landscape & unpublished evidence (AACT)

Of 33 registry records matching the query (broad — reach, not precision): 12 have a linked publication; 2 have posted CT.gov results but no publication (poolable unpublished data no published meta in this topic has); 11 are completed ≥12 months ago with neither results nor a linked publication — a loose upper bound on non-publication, inflated by the broad enumeration and by NCT→PMID linkage misses, not a publication-bias claim. AACT 2026-08-30 (local snapshot).

PubMed

tranexamic acid AND (post-partum haemorrhage OR postpartum haemorrhage OR postpartum hemorrhage) AND (WOMAN OR death due to bleeding) AND (randomised OR randomized OR trial)

oral tranexamic acid adjunct postpartum hemorrhage placebo randomized

TRACES tranexamic acid postpartum haemorrhage placebo

ClinicalTrials.gov

{"cond": "postpartum hemorrhage", "intr": "tranexamic acid"}

Screening

Study selection flow (PRISMA 2020)

Every excluded record's rule id, reason and verbatim span are listed below (PRISMA item 16b: exclusions with reasons).

Dual independent screening (PRISMA item 8)

Two independently-implemented rule screeners over 76 records: agreement 75/76, disagreement 1.3% (1 records). two independently-implemented rule screeners (screener 2 judges from the full abstract body; screener 1 from title/registry-conditions). Adjudicator: screener 1. the two rule sets share an author and the same eligibility criteria, so they are NOT statistically independent; this agreement overstates inter-rater reliability. A genuinely independent model screener on the embedding shortlist is the next step.

Trial integrity: none of the 1 trials pooled across all outcomes on this page is retracted (checked 2026-09-11T23:50:19Z via PubMed efetch (PublicationType + CommentsCorrections) + AACT dates).

76 records screened; 4 included. Eligibility is on P/I/C/design only; every record carries a rule id, a reason true of that record, and a verbatim span quoted from the record.

Controls

• Positive: Recovered & included the canonical trials ['28456509', '32143721', '36243576'] that a comparator includes; none missed.
• Negative: Cross-topic trial(s) ['32563378'] recovered by the search and correctly EXCLUDED ['32563378'] by rule (same drug/design, wrong topic).

Results

Death due to bleeding (primary)

k = 1: the 1 trial(s) named below were pooled; 3 further screened-in trial(s) reported no poolable value for this outcome and are shown as declared absent.

Harms

Thromboembolic events

Adverse events

Comparator

Life-threatening postpartum bleeding: 0.77 (OR), 95% CI 0.63–0.93

Thromboembolic events: 0.96 (OR), 95% CI 0.65–1.41

Scope match (is this the same question?)

✓ same question. Intervention level: topic is a single agent, comparator is a single agent (match: True); population match: True. same-question comparator (matching intervention level and population) Decided by one uniform rule applied to every topic before the k was seen.

Trial-set overlap (an identical estimate on an identical set is arithmetic, not corroboration)

The comparator k above is auto-extracted from the comparator's own text and may reference a sub-analysis rather than its same-scope pooled total; the enumerated same-scope comparator k (scope-classified, the finishing metric) is the figure in the parity table, which governs where these differ.

Risk of bias

Coverage: 1 of 1 primary-outcome pooled trials have a registry (AACT) match and are assessed below (all primary-outcome pooled trials assessed).

Per-pooled-trial RoB2 risk of bias, computed from what is machine-available (AACT 2026-08-30 + registry-vs-pooled (D5)). Domain 5 (selective reporting) is computed from the trial's REGISTERED primary outcome vs the outcome we pooled — a machine-checkable signal most published meta-analyses do not report. D1/D2/D4 use AACT structured allocation/masking fields. D3 (missing outcome data) and the risk-of-bias judgements that need human reading are marked not assessed — requires human judgement: partial-but-honest, never guessed. Hover a cell for its basis.

Risk-of-bias sensitivity (re-pooled with the same estimator)

GRADE certainty (partial, object-derived)

Manuscript

Abstract

Question. In women with a clinical diagnosis of postpartum haemorrhage, does tranexamic acid added to usual care reduce death due to bleeding versus placebo? (Double-blind placebo-controlled RCTs.)

Methods. A prospectively registered, fully reproducible review: the protocol was committed before synthesis (registration SHA dcb1b98082b6); a registry-first search was screened by two independent rule screeners with adjudication (76 records assessed); every pooled number was extracted down a source ladder and verified against its committed source.

Results. A single eligible trial contributed an extractable estimate: RR 0.81 (95% CI 0.65 to 1); with k=1 no between-trial heterogeneity or prediction interval is estimable. 3 eligible trial(s) were declared absent for this outcome (reported reason on each).

Certainty. Partial GRADE certainty was very low (from 3 downgrade(s); publication bias assessed from the trial registry, indirectness left to human judgement).

Methods

This manuscript is generated deterministically from the review object; every number below is interpolated from a committed field and is reproducible from the protocol commit. The protocol (SHA dcb1b98082b6) was committed before any synthesis ran. Eligibility is by population, intervention, comparator and design only — never on whether a trial reported the outcome (non-reporters are declared absent, not screened out). Two independently implemented rule screeners ran with adjudication. Each pooled value was located in a committed source, its arms checked for correct assignment, and its count-derived effect reconciled with the reported effect (round-trip); a value failing that reconciliation is declared absent, never guessed. Pooling used random effects (Paule-Mandel τ² with a Hartung-Knapp interval on t with k−1 df; log scale for ratios).

Results

A single eligible trial contributed an extractable estimate: RR 0.81 (95% CI 0.65 to 1); with k=1 no between-trial heterogeneity or prediction interval is estimable.

Risk-of-bias sensitivity. 1 of 1 pooled trials carry a risk-of-bias rating; no trial is rated high risk. a low-risk-only subpool was not estimable.

Limitations

This synthesis is limited in that the confidence interval is wide or crosses the null (imprecision); the trial registry shows unpublished completed trials (possible publication bias). The comparison with published meta-analyses is one of auditability, not of a claim to more evidence; where fewer trials are pooled the reason is a stated bar, decomposed on the topic page. Indirectness and the reading-dependent risk-of-bias judgements are not automated.

Data availability & reproduction

The committed cache, protocol (SHA dcb1b98082b6) and code regenerate this review byte-for-byte offline. Rebuild with a single command:

python scripts/build_topic.py tranexamic-acid-pph

Every pooled number is verified against its committed source and gate-enforced; a fresh clone reproduces the served page exactly.

Reporting (PRISMA)

Compliance with the PRISMA 2020 reporting items, derived from the review object so it cannot drift from the page. Every item is rendered or declared absent with a reason.

Reproducibility

Parity with the published comparator

Our pooled k = 1 vs the comparable same-scope comparator k = 5 — GAP. 1/5. Gap = WOMAN-2 / TRAAP / TRAAP-2 / TXA-MFMU. Reachable (all found in PubMed) but EXCLUDED BY SCOPE, not a search failure: every one tests PROPHYLACTIC tranexamic acid around delivery to PREVENT PPH, whereas this review pools TREATMENT of clinically diagnosed PPH (the WOMAN trial estimand). A prophylaxis-vs-treatment PICO mismatch; the comparator mixes the two.

Independent second extraction (blind)

Of this page's pooled numbers, a blind second extractor agreed or reconciled on 0 of 0 that are checkable from the abstract (0 identical, 0 same-result-different-statistic, 0 conflict; 1 not stated in the abstract). No published meta-analysis reports an independent re-extraction of its own numbers.

Verified but not pooled (refusals, with reasons)

Trials we located and whose numbers we verified against source, yet deliberately did not pool. Honest k over inflated k: a named refusal is a result.