This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Efficacy of Tranexamic Acid in Preventing Postpartum Haemorrhage After Elective Caesarean Section (NCT03463993), a randomized phase 3 study. The primary outcome is Number of Participants With Postpartum Haemorrhage (PPH).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03463993 |
| Phase | Phase 3 |
| Condition | Post Partum Hemorrhage |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 506 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Zimbabwe |
| Results posted | Yes |
2. Clinical Question
Population
Women undergoing elective caesarean section. The primary outcome is described for the intention-to-treat population, with follow-up up to 48 hours after caesarean section.
Intervention
Group A received tranexamic acid at 10mg/kg, administered slowly by intravenous infusion over 5 minutes, 10 minutes before skin incision. Prophylactic oxytocin was also administered on delivery of the baby.
Comparator
Group B received prophylactic oxytocin on delivery of the baby, without the study tranexamic acid intervention.
Primary question
Did the number of participants with postpartum haemorrhage differ between the groups during the period up to 48 hours after caesarean section? The registry record describes haemorrhage assessment using haematocrit and haemoglobin calculations, but does not report the group results or a comparative estimate.
The trial addresses whether adding tranexamic acid to prophylactic oxytocin is associated with a difference in postpartum haemorrhage after elective caesarean section. The registry record identifies postpartum haemorrhage as the primary outcome, but its description refers to two calculation approaches. It does not provide the event counts for either approach, a single effect estimate, or a confidence interval. Therefore, the clinical question can be stated, but the result of the comparison cannot be determined from the registry record.
3. Trial Design
The registry record describes a phase 3, randomized, open-label, parallel-group trial sponsored by the University of Zimbabwe. Its status is completed. The listed enrollment is 506. The brief summary describes an intended study of 1,162 women, so the registry record contains different figures for listed enrollment and intended enrollment; it does not explain the difference.
Participants were allocated to Group A, which received tranexamic acid as well as prophylactic oxytocin, or Group B, which received prophylactic oxytocin alone. The record describes tranexamic acid administration before skin incision and oxytocin administration on delivery of the baby. Masking is listed as none, meaning the trial is recorded as open-label rather than masked.
The primary outcome is the number of participants with postpartum haemorrhage, with a timeframe up to 48 hours after caesarean section. The primary outcome description says it was based on haematocrit calculation and haemoglobin calculation. The record also lists secondary outcomes covering estimated blood loss, transfusion, additional uterotonics, tranexamic acid side effects, emergency surgery for postpartum haemorrhage, hospital stay, and neonatal outcomes.
The registry record lists 13 outcome measures and 7 analyses, but does not provide the detailed analysis methods or outcome results needed to interpret those analyses. It also does not report the recruitment flow, exclusions from analysis, or the reason that listed enrollment differs from the intended enrollment in the summary.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Group A | Group B |
|---|---|---|
| STARTED | 253 | 253 |
| COMPLETED | 224 | 227 |
| NOT COMPLETED | 29 | 26 |
Reasons for not completing this period:
| Reason | Group A | Group B |
|---|---|---|
| Lost to Follow-up | 7 | 8 |
| Withdrawal by Subject | 2 | 0 |
| Protocol Violation | 4 | 1 |
| Had a vaginal delivery prior to caesarean delivery | 9 | 11 |
| Had emergency caesarean delivery prior to elective caesarean delivery | 7 | 6 |
Analysis population for the primary outcome, as defined in the registry: Intention-to-treat population
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Group A | Group B | Total |
|---|---|---|---|---|
| Participants analysed | 224 | 227 | 451 | |
| Age, Continuous | years | 29.5 (SD 6.0) | 29.7 (SD 6.5) | 29.6 (SD 6.3) |
| Sex: Female, Male: Female | Participants | 224 | 227 | 451 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Black African | Participants | 224 | 227 | 451 |
| Region of Enrollment: Zimbabwe | participants | 224 | 227 | 451 |
| Gestational age | Weeks | 39 (38 to 40) | 39 (38 to 40) | 39 (38 to 40) |
| HIV status: Positive | Participants | 27 | 35 | 62 |
| HIV status: Negative | Participants | 186 | 187 | 373 |
| HIV status: Unknown | Participants | 11 | 5 | 16 |
| Multiple pregnancy | Participants | 6 | 6 | 12 |
| Placenta praevia | Participants | 5 | 1 | 6 |
| Uterine fibroids | Participants | 5 | 1 | 6 |
| Weight | kilograms | 78.3 (SD 14.9) | 78.2 (SD 15.2) | 78.3 (SD 15.0) |
| Body mass index | kg/m^2 | 29.8 (SD 5.3) | 30.5 (SD 5.5) | 30.1 (SD 5.4) |
| Number of previous caesarean sections: 1 | Participants | 82 | 87 | 169 |
| Number of previous caesarean sections: 2 | Participants | 38 | 44 | 82 |
| Number of previous caesarean sections: ≥3 | Participants | 5 | 13 | 18 |
| Number of previous caesarean sections: 0 | Participants | 99 | 83 | 182 |
| Previous surgery | Participants | 10 | 11 | 21 |
| Anaemia (Hb < 11 g/dl) | Participants | 44 | 51 | 95 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Postpartum Haemorrhage (PPH), measured over Up to 48 hours post-caesarean section.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with postpartum haemorrhage, assessed up to 48 hours after caesarean section. The registry description names two ways of calculating the outcome: using haematocrit and using haemoglobin. The brief summary defines postpartum haemorrhage as blood loss equal to or more than 1,000ml and describes calculation from the difference in haematocrit before surgery and 48 hours after surgery. The record does not explain how the haemoglobin-based calculation was defined or how the two approaches were handled in the primary analysis.
General: A binary endpoint records whether each participant meets a specified outcome definition. Reporting the number of participants with an event can make the outcome clinically interpretable, but the group counts alone do not explain the uncertainty around a treatment comparison. A comparative estimate and its confidence interval are useful for showing both the direction and precision of the observed difference.
The registry identifies the intention-to-treat population for this outcome, but does not report the event counts, comparative estimate, confidence interval, or outcome-specific missing-data handling. The endpoint is therefore described, but its observed treatment-group comparison is not available in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the trial question and the planned primary outcome, but does not report the primary outcome results. It gives no group-specific postpartum haemorrhage counts, effect estimate, confidence interval, or p-value. As a result, the size and precision of the treatment comparison cannot be assessed from the record, and no conclusion about the observed primary outcome difference can be drawn.
The outcome description requires particular care because it mentions postpartum haemorrhage based on haematocrit calculation and postpartum haemorrhage based on haemoglobin calculation. The brief summary gives a threshold of blood loss equal to or more than 1,000ml and describes a haematocrit-based calculation, while the primary outcome description names both calculation approaches. The registry record does not clarify whether these were separate analyses, alternative definitions, or how a primary result was selected. It also does not report results for either approach.
The listed safety data show zero serious adverse events in Group A and zero in Group B. The record also lists 7 other adverse events in Group A and 3 in Group B. These counts should be read alongside the listed at-risk counts of 224 and 227, respectively. The record does not give the terms for the other events, their severity, timing, attribution, or a comparative statistical analysis. The counts alone do not establish whether the groups differed in safety.
Randomization is intended to support a fair comparison by allocating participants to groups, while open-label conduct means masking is not listed. The registry record does not report details of sequence generation, allocation concealment, adherence, or implementation. These details are relevant to evaluating how the trial was conducted, but should not be inferred from the design labels.
The record lists 506 enrolled participants, whereas its brief summary says that investigators intended to study 1,162 women. It does not explain this difference, and neither figure supplies the missing primary outcome data. The completion status indicates the trial is recorded as completed; it does not, by itself, provide evidence about the result or its precision.
Overall, the registry record allows a description of the comparison and endpoint but not an efficacy interpretation. The posted safety counts are limited and lack event descriptions. The result, its uncertainty, and the relation between the two stated primary-outcome calculations are not reported in the registry record.
9. Statistical Methods Explained
What does randomization contribute?
General: Random allocation is intended to make treatment groups comparable, on average, with respect to factors known and unknown at the time of allocation. This supports interpreting a group comparison as an estimate of the effect of assignment, provided that allocation and follow-up are handled appropriately. Randomization does not guarantee identical groups, and it does not replace reporting the methods, participant flow, outcomes, and uncertainty.
The registry record labels the trial randomized, but does not report how the sequence was generated or whether allocation was concealed. These procedural details are not reported in the registry record. The record also does not provide participant flow or explain how many assigned participants contributed to each outcome analysis.
What does an open-label parallel design mean?
General: In a parallel-group design, each participant is assigned to one group and outcomes are compared between groups. Open-label means masking is not listed; awareness of assigned treatment can affect participant behavior, care, outcome assessment, or reporting, depending on the endpoint and trial procedures. These are general considerations, not claims about what occurred in this trial.
The registry describes Group A as receiving tranexamic acid alongside oxytocin and Group B as receiving oxytocin alone. It does not report blinding of outcome assessors or other safeguards for outcome measurement.
How should a binary endpoint be analyzed?
General: A binary outcome classifies each participant as having or not having an event under a defined rule. A complete comparison commonly reports group event counts and denominators, followed by a measure of the difference or relative association and a confidence interval. A confidence interval describes the range of values reasonably compatible with the data and analysis assumptions; a wider interval indicates less precision. A p-value addresses compatibility with a specified null hypothesis, but does not measure clinical importance or establish that an effect is absent.
The registry record gives no primary event counts or comparative statistics. The outcome definition also refers to haematocrit and haemoglobin calculations, without explaining how those are combined or distinguished in the analysis. Therefore, a primary effect measure and its precision cannot be described from this record.
Why does the analysis population matter?
General: An intention-to-treat analysis generally compares participants according to their randomized group, regardless of whether they followed the assigned intervention exactly. This approach can preserve the benefit of randomization, but the exact handling of missing outcomes and deviations still needs to be described. The registry identifies the intention-to-treat population for the primary outcome; it does not explain how missing measurements, protocol deviations, or unavailable outcomes were treated.
What can be said about planning?
The record includes general planning assumptions for an illustration: two-sided significance level 0.05, equal allocation, and a normal approximation, with the effect to detect expressed as a stated fraction of an observed effect. It also distinguishes planning outputs for participants per arm from total event counts for time-to-event methods. However, no numerical planning results, observed effect, or effect fractions are included in the registry record. These assumptions should not be mistaken for the trial's own design justification, which is not reported in the registry record. Any sample-size illustration is a planning exercise, not observed power.
The registry record does not report whether interim analyses were planned or conducted, the primary statistical model, adjustment variables, or the exact tests used. Those methods are not reported in the registry record, so the analysis cannot be reconstructed from the design description alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 13 outcome measures and 7 analyses. The primary outcome description refers to postpartum haemorrhage calculated using haematocrit and using haemoglobin. It does not clarify whether these constitute separate primary analyses or how the primary result was selected. The record also lists multiple secondary outcomes, including estimated blood loss, transfusion, additional uterotonics, side effects, emergency surgery, hospital stay, and neonatal measures.
General: When several outcomes or analyses are assessed, the chance of at least one apparently notable result can increase if each is interpreted without accounting for the number of comparisons. A prespecified hierarchy, adjustment procedure, or clear distinction between primary and exploratory analyses can help readers understand how to interpret multiple results. The registry record does not report a multiplicity strategy, an outcome hierarchy beyond identifying the primary outcome, or how the 7 analyses relate to the listed measures.
The primary outcome population is identified as intention-to-treat, but missing-data procedures are not reported in the registry record. The record does not state how missing haematocrit or haemoglobin measurements, incomplete follow-up, or other unavailable outcomes were handled. It also does not report analysis-specific denominators or sensitivity analyses for missing data. These omissions limit assessment of how robust any eventual comparison would be, but the primary outcome results themselves are also not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Group A | 0 | 224 | 0.0% |
| Group B | 0 | 227 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Group A | 0 of 224 |
| Group B | 0 of 227 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Group A | 7 of 224 |
| Group B | 3 of 227 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Group A | Group B |
|---|---|---|---|
| Hypotension | Cardiac disorders | 3 of 224 | 1 of 227 |
| Headache | Nervous system disorders | 1 of 224 | 1 of 227 |
| Nausea | Gastrointestinal disorders | 2 of 224 | 0 of 227 |
| Vomiting | Gastrointestinal disorders | 1 of 224 | 1 of 227 |
The registry safety figures list zero serious adverse events among 224 participants at risk in Group A and zero among 227 participants at risk in Group B. It also lists 7 other adverse events in Group A and 3 in Group B. The record does not provide the terms describing those other events, so their nature cannot be evaluated from these counts.
General: An event count is a descriptive measure, not by itself a comparison of risk. Interpretation depends on how events were defined and collected, how long participants were followed, whether events could be counted more than once per person, and whether the groups were assessed consistently. A comparative estimate with uncertainty is needed to assess how precisely the data distinguish between groups.
The registry record does not report a statistical comparison of these safety figures, event timing, severity details for the other events, attribution to treatment, or additional information about monitoring. Zero recorded serious events in each group does not establish that serious events cannot occur; it describes only the counts reported in this record. The figures also do not establish that the other events were caused by, or unrelated to, either intervention.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the trial compared tranexamic acid plus prophylactic oxytocin with prophylactic oxytocin alone in women undergoing elective caesarean section. It identifies postpartum haemorrhage up to 48 hours after caesarean section as the primary endpoint and describes haematocrit- and haemoglobin-based calculations. Those details frame the research question, but they are not the result of the comparison.
The record does not report primary event counts, an effect estimate, a confidence interval, or a p-value. Consequently, it does not show the direction, size, or precision of the primary outcome comparison. It also does not explain how the two stated calculation approaches were handled. A completed trial status cannot fill these gaps.
The adverse event figures provide limited descriptive information: there were zero listed serious events in each group, and other adverse event counts of 7 and 3. Without event descriptions and comparative uncertainty, these data do not establish a safety difference or explain the clinical significance of the events.
General: Statistical interpretation separates the observed estimate from its uncertainty and from the practical importance of an effect. A result that is imprecise may be compatible with a range of effects; absence of a reported result is not evidence of no effect. Here, because the primary outcome comparison is not reported in the registry record, even the observed estimate and its uncertainty are unavailable.
The record therefore supports a description of the trial design, intervention contrast, endpoint, and limited adverse-event counts. It does not support a conclusion about whether the intervention changed postpartum haemorrhage outcomes or about the comparative safety of the groups.
13. Why This Trial Matters Statistically
This trial is statistically relevant because it poses a randomized comparison of an added intervention against a group receiving prophylactic oxytocin alone. Randomization is a design feature intended to support causal comparison, while the open-label designation highlights the importance of understanding how outcomes were measured and analyzed.
The primary outcome is a participant-level event count, but its description names both haematocrit-based and haemoglobin-based calculations. Clear definitions and a stated analysis hierarchy are important when outcome descriptions permit more than one calculation. The registry record does not explain the relationship between these approaches or report their results, leaving the primary comparison unresolved.
The record also illustrates why enrollment information and outcome reporting answer different questions. It lists enrollment of 506 and describes an intended enrollment of 1,162 in the brief summary, without explaining the difference. Neither figure indicates the treatment effect or its precision. Similarly, a completed status does not substitute for outcome estimates and uncertainty intervals.
General: Clinical trial results are most informative when they pair a clearly defined endpoint with group data, an effect estimate, and a measure of precision. Transparent reporting of analysis populations, missing-data handling, and multiplicity also helps readers judge how much confidence to place in a result. Those elements are not reported for the primary comparison in this registry record, so the research question is visible but its statistical answer is not.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
A central limitation of the registry record is that it does not report the primary outcome results. No group-specific counts, comparative estimate, confidence interval, or p-value are available. The primary endpoint description also refers to haematocrit- and haemoglobin-based calculations, without explaining their definitions, relationship, or analysis hierarchy.
The brief summary describes intended enrollment of 1,162 women, while listed enrollment is 506. The registry record does not explain the difference, report recruitment flow, or state how many participants contributed to each analysis. It identifies the primary population as intention-to-treat but does not describe missing-data handling, deviations from assigned treatment, or sensitivity analyses.
Although the study is recorded as randomized and open-label, the sequence-generation and allocation-concealment methods are not reported in the registry record. Outcome assessor masking is also not described. The statistical model, adjustment methods, multiplicity strategy, and interim-analysis procedures are not reported in the registry record.
Safety reporting is limited to event counts. The record does not provide descriptions of the other adverse events, their timing, or a comparative analysis. Secondary outcome results are not included in the registry record recorded for this trial. These limitations concern the available registry information and should not be taken as evidence that the trial did or did not perform any unreported procedures.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Efficacy of Tranexamic Acid in Preventing Postpartum Haemorrhage After Elective Caesarean Section — NCT03463993.
- Registry record last updated 2022-06-01; status last verified 2022-05.
- Results first posted 2022-04-20.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes a completed, randomized, open-label, parallel-group phase 3 trial sponsored by the University of Zimbabwe. It compares tranexamic acid plus prophylactic oxytocin with prophylactic oxytocin alone in elective caesarean section. Listed enrollment is 506; the brief summary states that 1,162 women were intended for the study, and the difference is not explained.
The primary outcome is the number of participants with postpartum haemorrhage up to 48 hours after caesarean section, described using haematocrit and haemoglobin calculations. The primary outcome results and statistical comparison are not reported in the registry record. Safety figures list zero serious adverse events in each group and other adverse event counts of 7 and 3, but event details and comparative analyses are not reported.