The Lancet May 27, 2017

Effect of early tranexamic acid administration on mortality, hysterectomy, and other morbidities in women with post-partum haemorrhage (WOMAN): an international, randomised, double-blind, placebo-controlled trial

WOMAN Trial Collaborators

Bottom Line

In women with postpartum hemorrhage, early administration of tranexamic acid significantly reduced deaths due to bleeding and the need for laparotomy, despite not significantly lowering the primary composite outcome of all-cause mortality or hysterectomy.

Key Findings

1. The primary composite outcome of death from all causes or hysterectomy was not significantly reduced with tranexamic acid compared to placebo (5.3% vs. 5.5%; RR 0.97, 95% CI 0.87-1.09; P=0.65).
2. Tranexamic acid significantly reduced the secondary outcome of death due to bleeding (1.5% vs. 1.9%; RR 0.81, 95% CI 0.65-1.00; P=0.045).
3. The mortality benefit for bleeding was most pronounced when tranexamic acid was administered within 3 hours of birth (1.2% in the TXA group vs. 1.7% in the placebo group; RR 0.69, 95% CI 0.52-0.91; P=0.008), with no benefit observed if given after 3 hours.
4. The need for laparotomy to control bleeding was significantly lower in the tranexamic acid group (0.8% vs. 1.3%; RR 0.64, 95% CI 0.49-0.85; P=0.002).
5. There was no significant difference in the incidence of adverse events, including venous thromboembolic events (0.3% in both groups; RR 0.88, 95% CI 0.54-1.43).

Study Design

Design
Randomized Controlled Trial
Double-Blind
Sample
20,060
Patients
Duration
42 days
Median
Setting
Multicenter, 21 countries
Population Women aged 16 years and older with a clinical diagnosis of post-partum hemorrhage following a vaginal or cesarean delivery.
Intervention Intravenous tranexamic acid 1 g infused over 10 minutes (a second 1 g dose could be given if bleeding continued after 30 minutes or restarted within 24 hours).
Comparator Matching intravenous placebo (0.9% sodium chloride).
Outcome Composite of death from all causes or hysterectomy within 42 days of delivery.

Study Limitations

The trial failed to meet its primary composite endpoint, requiring the main clinical conclusions to be drawn from prespecified secondary outcomes and subgroup analyses.
The hysterectomy component of the primary outcome was often a subjective clinical decision made concurrently with randomization, rendering it an insensitive measure of the drug's true hemostatic effect.
The overall absolute risk reduction for death due to bleeding was small (0.4%), leading to a low fragility index.
The study was conducted primarily in low- and middle-income countries, which may limit the generalizability of the mortality benefit to high-resource settings where baseline maternal mortality is lower and advanced interventions are readily available.

Clinical Significance

Despite the negative primary composite outcome, the WOMAN trial demonstrated that the early use of tranexamic acid reduces bleeding-related maternal mortality and the need for major surgical interventions (laparotomy) without increasing thromboembolic risk. Because tranexamic acid is inexpensive, heat-stable, and easily administered, the World Health Organization subsequently updated its global guidelines to strongly recommend early IV tranexamic acid (within three hours of birth) as a standard pillar of postpartum hemorrhage management.

Historical Context

Postpartum hemorrhage is the leading cause of maternal mortality worldwide, historically accounting for over 100,000 deaths annually. Following the landmark CRASH-2 trial (2010), which demonstrated that tranexamic acid safely reduced mortality in trauma patients with severe bleeding, the WOMAN trial was designed to evaluate if this survival benefit extended to obstetric hemorrhage. Its findings firmly established the life-saving role of antifibrinolytics in the obstetric resuscitation algorithm.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

How does tranexamic acid work at a molecular level, and why does this mechanism make sense for the treatment of postpartum hemorrhage compared to standard uterotonics?

Key Response

TXA is a synthetic lysine analog that competitively inhibits the activation of plasminogen to plasmin, preventing fibrin degradation. While uterotonics like oxytocin address uterine atony by inducing contraction, TXA stabilizes the clots formed at the placental site, making them synergistic in management.

Resident
Resident

The WOMAN trial emphasized the importance of early administration of TXA. Based on the trial's data, what is the critical time window for administering TXA in PPH, and how does administering it after this window affect patient outcomes?

Key Response

The trial showed a significant reduction in death due to bleeding if TXA is given within 3 hours of birth. Beyond 3 hours, there was no benefit, and there was even a trend toward harm. This dictates that residents must administer TXA as a first-line adjunct immediately rather than waiting for other measures to fail.

Fellow
Fellow

The WOMAN trial did not show a reduction in hysterectomy rates despite reducing bleeding-related deaths. How can this discrepancy be explained pathologically and clinically in the context of severe PPH management?

Key Response

In severe PPH, hysterectomy is often a rapid, life-saving decision made by obstetricians before TXA has time to exert its full hemostatic effect. Additionally, hysterectomies are often performed for anatomical causes like placenta accreta or severe atony, where TXA's anti-fibrinolytic action alone cannot reverse the mechanical defect necessitating surgical removal.

Attending
Attending

As an attending leading a labor and delivery unit, how should the finding that TXA reduced laparotomy for bleeding but not hysterectomy shift your multidisciplinary massive hemorrhage protocols, and what is the key teaching point to prevent delayed administration?

Key Response

The key shift is incorporating TXA empirically upfront within the first hour rather than as a salvage therapy. The teaching point is to decouple the decision to give TXA from the decision to operate; TXA buys time and reduces mortality early on, but providers must not delay definitive surgical management if source control is anatomically required.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The authors of the WOMAN trial increased the sample size and repowered the study specifically to detect a reduction in death from bleeding alone, after realizing the hysterectomy rate was driven by provider decisions. What are the methodological implications of modifying a trial's endpoints based on blinded aggregate event rates?

Key Response

Modifying endpoints or sample sizes based on blinded aggregate data is a valid adaptive design but risks diluting the original primary outcome's power if not meticulously planned. This highlights the methodological challenge of using composite endpoints that combine a physiological outcome like death with a highly subjective, provider-dependent intervention like hysterectomy.

Journal Editor
Journal Editor

From an editorial standpoint, how should a journal handle the publication of a trial where the primary composite outcome is technically negative, but a highly clinically relevant secondary or redefined outcome like death due to bleeding is statistically significant?

Key Response

A rigorous editor must require authors to transparently report the primary composite as non-significant in the abstract's first line of results to prevent spin. However, editors must balance strict adherence to protocol-driven primary endpoints with the pragmatic reality that death due to bleeding is a crucial finding that warrants spotlighting, provided all protocol amendments are fully disclosed.

Guideline Committee
Guideline Committee

Following the publication of the WOMAN trial, how should international guidelines such as WHO or ACOG grade the recommendation for TXA in PPH, specifically regarding its timing and role relative to standard uterotonics?

Key Response

Guidelines should offer a strong recommendation with high-quality evidence for the use of IV TXA within 3 hours of birth for PPH. Existing WHO guidelines were updated directly because of this trial to strongly recommend early TXA not as a replacement for standard uterotonics, but as a critical adjunct, explicitly recommending against its use if more than 3 hours have elapsed.

Clinical Landscape

Noteworthy Related Trials

2010

CRASH-2 Trial

n = 20,211 · Lancet

Tested

Tranexamic acid 1g intravenously over 10 min followed by 1g over 8h

Population

Adult trauma patients with or at risk of significant bleeding

Comparator

Placebo

Endpoint

All-cause mortality within 4 weeks

Key result: Tranexamic acid significantly reduced all-cause mortality and death due to bleeding without increasing the risk of fatal or non-fatal vaso-occlusive events.
2018

TRAAP Trial

n = 4,079 · NEJM

Tested

Tranexamic acid 1g intravenously

Population

Women undergoing vaginal delivery

Comparator

Placebo

Endpoint

Postpartum hemorrhage of at least 500 mL or use of additional uterotonics

Key result: Prophylactic tranexamic acid did not significantly reduce the primary composite outcome of postpartum hemorrhage or need for additional uterotonics.
2021

TRAAP2 Trial

n = 4,551 · NEJM

Tested

Tranexamic acid 1g intravenously

Population

Women undergoing cesarean delivery before or during labor

Comparator

Placebo

Endpoint

Postpartum hemorrhage greater than 1000 mL or requirement for red-cell transfusion within 2 days

Key result: Prophylactic tranexamic acid did not significantly lower the risk of severe postpartum hemorrhage or red-cell transfusion compared to placebo.

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