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 Carbetocin Myocardium Trial 2014 Part 2 (NCT03899961), a randomized phase 4 study. The primary outcome is Plasma Concentration Troponin I.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03899961 |
| Phase | Phase 4 |
| Condition | Pregnancy Complications |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 240 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Oslo University Hospital |
| Results posted | Yes |
2. Clinical Question
Population
The primary outcome is described for a biobank sample. The trial concerns pregnancy complications, and the study summary says potential myocardial effects should be examined in healthy women. The registry record does not report enough eligibility detail to establish who was included in the analyzed biobank sample or how it relates to the full enrolled group.
Intervention
Participants in one randomized arm received oxytocin 2.5 U i.v. The study summary describes the question as whether the myocardial effects associated with oxytocin differ from those associated with carbetocin. The record does not provide further administration details beyond the listed drug and dose.
Comparator
The comparator was carbetocin 100 µg i.v. The primary comparison is between the two assigned drugs, rather than between either drug and no treatment. The posted results do not establish whether the analysis accounts for other participant characteristics or clinical circumstances.
Primary question
The primary endpoint was plasma concentration of troponin I at 8 hours. The reported analysis estimates the group difference in the median. The statistical question is whether the posted data indicate a difference in that marker between the randomized arms, and how precisely the difference is estimated. This is not itself a comparison of clinical cardiac events.
The study summary gives a clinical rationale for comparing the drugs: it notes prior concerns about cardiovascular effects associated with oxytocin and says the specific myocardial effects of oxytocin and carbetocin had not been compared in a clinical study. It also describes why information about possible differences could be relevant when considering standard medication in delivery planning for women with heart disease. Those statements motivate the research question; they are not findings from this trial. The present page therefore focuses on the registered comparison and its posted outcome data, rather than inferring clinical consequences from a biomarker result.
3. Trial Design
The registry describes a phase 4, randomized, quadruple-masked, parallel-group trial sponsored by Oslo University Hospital. It records an enrollment of 240 and a completed status. The recorded start date is 2019-04-02, and the primary completion date is 2022-03-01. These are the registry’s design and status details; they do not by themselves describe when each participant entered or completed follow-up.
The two randomized groups received oxytocin 2.5 U i.v. or carbetocin 100 µg i.v. The primary outcome is recorded for a biobank sample, with 109 participants in the oxytocin arm and 99 in the carbetocin arm contributing to the posted primary summary. These outcome counts are not the same as the overall enrollment figure. Reasons for the difference, including any missing samples or exclusions, are not reported in the registry record.
The primary endpoint was plasma concentration of troponin I at 8 hours. The record describes the outcome using medians and full ranges, and the sponsor reports a median regression analysis of the group difference. The registry also lists blood loss, uterine tone grade, and side effects among secondary outcomes. Blood loss is recorded at 10 hours and side effects at 10 min. The detailed posted secondary results cover blood loss and side effects; further results for uterine tone grade are not reported in the registry record.
The allocation sequence generation, concealment procedures, masking implementation, eligibility criteria, and details of the analysis population are not reported in the registry record. The design label indicates the intended trial structure, but it does not answer these operational questions. Nor does the record state the planned sample-size justification or whether any interim analyses were conducted.
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 | Oxytocin | Carbetocin |
|---|---|---|
| STARTED | 121 | 119 |
| COMPLETED | 112 | 103 |
| NOT COMPLETED | 9 | 16 |
Reasons for not completing this period:
| Reason | Oxytocin | Carbetocin |
|---|---|---|
| -delivery prior to | 2 | 7 |
| req general anesth | 1 | 2 |
| capacity | 5 | 6 |
| Withdrawal by Subject | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: Biobank sample
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.
Population: Modified ITT population
| Characteristic | Unit | Oxytocin | Carbetocin | Total |
|---|---|---|---|---|
| Participants analysed | 112 | 103 | 215 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 112 | 103 | 215 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 34.5 (23.4 to 50.9) | 35.0 (24.1 to 47.5) | 34.8 (23.4 to 50.9) |
| Sex: Female, Male: Female | Participants | 112 | 103 | 215 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 112 | 103 | 215 |
| Region of Enrollment: Norway | Participants | 112 | 103 | 215 |
| Troponin I | ng/L | 1.0 (1.0 to 48.7) | 1.0 (1.0 to 19.2) | 1.0 (1.0 to 48.7) |
6. Primary Endpoint
The registry lists the primary outcome as Plasma Concentration Troponin I, measured over 8 hours.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | ng/L |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is plasma concentration of troponin I, measured in ng/L at 8 hours, in a biobank sample. Troponin I is a biomarker used to assess myocardial cell injury. A blood concentration can provide information about a biological response, but it is not the same as a clinical diagnosis or an assessment of symptoms, longer-term effects, or major cardiac events. The registry’s primary question is a comparison between treatment groups, not a threshold-based diagnosis for an individual participant.
The posted arm summaries report a median of 1.2 ng/L in each group. The full range is 1.0 to 47.0 ng/L for oxytocin and 1.0 to 19.5 ng/L for carbetocin. A median describes the midpoint of the observed values after ordering them; the full range shows the lowest and highest posted values. Range endpoints can be influenced by extreme observations, so they should not be read as a description of where most participants’ values lie.
In general, a biomarker is useful when it captures a biological process relevant to the research question and can be measured consistently. Its usefulness does not make it a substitute for patient-important outcomes. Here, the endpoint addresses the registered question about troponin I concentration at the specified time. Whether any biomarker difference corresponds to clinically meaningful effects is not established by this endpoint alone and is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The sponsor’s primary analysis estimates a median difference of 0 ng/L between the randomized groups, with a 95% confidence interval from -1.09 to 1.09 ng/L and p = 0.05. The posted arm medians are both 1.2 ng/L. The point estimate therefore sits at zero, while the interval includes values on either side of zero. The interval communicates uncertainty in the estimated group difference; it is not a range containing a stated proportion of individual participants’ troponin values.
In general, a confidence interval describes a range of estimates compatible with the data and the statistical model, at the stated confidence level. Here, its width indicates that the analysis does not pin the median difference to a single precise value. The interval includes no difference as well as differences in either direction, so the result should not be reduced to a claim that the groups are identical. Nor should the point estimate alone be treated as proof that there is no difference. The registry does not report a prespecified equivalence or non-inferiority margin that would allow a formal conclusion of equivalence.
The reported p value is 0.05. A p value summarizes how compatible the observed data are with a specified null model under the analysis assumptions; it is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The registry’s reported estimate and interval are the central information for judging magnitude and precision. The p value should not be used as a stand-alone verdict.
The endpoint summaries show the same median in both arms, but their ranges differ. Ranges describe extremes and do not on their own establish a difference in the overall distributions. The reported median regression analysis is the sponsor’s group-level analysis; it should be interpreted in light of the outcome definition, the analyzed biobank sample, and the model details that are available in the record. The full model specification is not reported in the registry record.
These findings concern troponin I at 8 hours in the posted sample. They do not establish whether either drug changes clinical cardiac outcomes, whether any biomarker difference persists, or how results apply beyond the participants represented in this analysis. The record also lists secondary measures, but those results are exploratory in the absence of a reported multiplicity plan. Overall, the posted primary result is centered on no median difference, with uncertainty that allows effects in either direction and no registered equivalence margin to define what would count as sufficiently small.
9. Statistical Methods Explained
The primary outcome is summarized with a median and full range, and the registry identifies median regression as the analysis method for the group difference. These choices are aligned with a question about a difference in medians rather than a difference in means. The posted results give group summaries and a model-based median difference with a confidence interval and p value. The model description in the registry record is incomplete, so important implementation details cannot be recovered from the posted wording.
What does a median describe?
In general, the median is the central ordered observation: half the observed values are no higher and half are no lower, allowing for ties and the details of the sample. Unlike the mean, it is less affected by very large or very small values. This can be useful for outcomes whose distributions are skewed or contain extreme observations. A median, however, does not describe the full distribution. Two groups can have the same median but differ in spread, shape, or the frequency of extreme values. That is why the arm summaries and the regression estimate should be considered together, without treating the medians as a complete account of the data.
What does median regression estimate?
In general, median regression models a conditional median rather than a conditional mean. It estimates how the median outcome differs between groups under the model’s specification. The reported estimate is a median difference of 0, with the interval and p value reported alongside it. The registry does not state the full model formula, any covariates, or whether the analysis adjusts for baseline values. The primary outcome description refers to a group difference in plasma concentration, while the method wording refers to a change analysis; the precise definition of that change is not reported in the registry record. This limits the ability to reproduce or fully audit the analysis from the posted description.
How should the confidence interval be read?
In general, a confidence interval expresses uncertainty about an estimated quantity under the analysis model and its assumptions. The 95% interval for this median difference extends from -1.09 to 1.09 ng/L. Since it crosses zero, it is compatible with a range of estimates that includes no group difference and differences in either direction. It does not show that every value in the interval is equally plausible, nor does it describe the range of individual results. Precision is about how narrowly the group contrast is estimated; clinical relevance requires a separate judgment and, ideally, a prespecified threshold grounded in the question being studied. No such threshold is reported in the registry record.
Why can ranges and model estimates tell different parts of the story?
The full ranges in the arm summaries display the observed minimum and maximum values. They can be sensitive to a small number of unusual observations and do not convey how values are distributed between the endpoints. Median regression instead targets a central feature of the group outcome. Differences in the largest observed value do not automatically imply a difference in medians, just as equal medians do not imply identical distributions. In general, plots can help reveal shape and unusual observations, but their interpretation still depends on the analysis population and measurement process. The plots and tables should therefore be read as complementary descriptions, not interchangeable tests.
What do the secondary planning illustrations mean?
The sample-size section uses simple, unadjusted recalculations based on the observed secondary effects. The registry’s planning assumptions specify a two-sided significance level of 0.05, equal allocation between arms, a normal approximation, and effects set to stated fractions of the observed effect. The tables express the planning illustrations as participants per arm for 80% power and participants per arm for 90% power. They are not the trial’s original design justification, and they are not observed power. Because they use effects estimated from the posted data, they are illustrations of how planning requirements change under those assumptions, not evidence that a future study will achieve a particular result. The registry does not report the original sample-size calculation or its assumptions.
For secondary outcomes, the posted comparison calculations are unadjusted. In general, an unadjusted p value assesses a particular comparison without accounting for the fact that multiple outcomes or analyses may be examined. The registry does not report a multiplicity adjustment or a prespecified hierarchy for the secondary outcomes. Consequently, secondary p values should be treated as descriptive or exploratory rather than as a set of confirmatory tests. The record reports one primary analysis, but it does not provide enough detail to establish the complete analysis plan, handling of missing data, or analysis population definitions.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Median regression model for the change f | Median Difference (Net) 0 | -1.09 to 1.09 | 0.050 |
The primary result is the sponsor’s reported analysis: a median difference of 0 ng/L, with a 95% confidence interval from -1.09 to 1.09 ng/L and p = 0.05. The registry identifies median regression as the method. This is the analysis to use when describing the primary outcome because no simple recalculated primary comparison is available from the posted summary statistics. The registry notes that a two-arm comparison is not estimable from those summary values for this outcome type.
The secondary tables include simple unadjusted recalculations from the posted arm summaries. Those calculations are not a replacement for a sponsor-reported model, and they do not recreate any covariate adjustment or other modeling choices. The record does not report sponsor analyses for the posted secondary outcomes. It also does not give the full primary model specification, so an independent reproduction of that model is not possible from the registry description alone.
The posted record does not flag a discrepancy between a sponsor estimate and a recalculated primary estimate. More importantly, there is no recalculated primary estimate to set against the sponsor’s result. Readers should distinguish the sponsor’s reported primary model from the secondary planning illustrations and unadjusted comparisons, which serve different purposes.
11. Multiplicity, Missing Data and Analysis Populations
The registry identifies one primary outcome and lists several secondary outcomes, but the posted record does not describe how the analysis handled multiplicity. It does not report a testing hierarchy, a family of outcomes for adjustment, or a procedure to control the chance of false-positive findings across multiple comparisons. Therefore, the secondary comparison p values should be read as unadjusted. They can describe the evidence for each individual comparison under its own model, but they do not establish a confirmatory conclusion across the full outcome set.
The record reports 240 enrolled participants, while the primary biobank summaries include 109 in the oxytocin arm and 99 in the carbetocin arm. For the secondary analyses, the arm counts differ again. The registry does not explain these differences, specify whether participants were excluded from particular analyses, or report how missing outcome measurements were handled. It does not state whether an intention-to-treat, per-protocol, or other analysis population was used. These details matter because the analyzed participants and missingness process can affect how representative the posted estimates are of the randomized groups.
In general, missing data are important when the probability of an outcome being unavailable is related to the outcome itself or to participant characteristics. Analysts may use different approaches depending on why data are missing and what assumptions are defensible. The registry does not provide enough information to assess those mechanisms or determine whether any imputation or sensitivity analyses were performed. It is therefore not possible to infer from the posted arm counts alone why the analysis denominators differ from enrollment.
The sample-size planning section is a separate, post hoc illustration based on observed secondary effects. The registry states assumptions of two-sided significance level 0.05, equal allocation, a normal approximation, and target effects defined as fractions of the observed effects. These illustrations do not reveal the original trial’s design assumptions. A sample-size justification, interim analysis plan, and any stopping rules are not reported in the registry record. These omissions limit assessment of how the trial was originally planned and how completely the posted analyses follow that plan.
12. 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 |
|---|---|---|---|
| Oxytocin | 0 | 112 | 0.0% |
| Carbetocin | 0 | 103 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Oxytocin | 0 of 112 |
| Carbetocin | 0 of 103 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Oxytocin | 50 of 112 |
| Carbetocin | 55 of 103 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Oxytocin | Carbetocin |
|---|---|---|---|
| Feeling hot | General disorders | 23 of 112 | 27 of 103 |
| flushing | Vascular disorders | 11 of 112 | 8 of 103 |
| nausea | Gastrointestinal disorders | 8 of 112 | 10 of 103 |
| Chest pain | Cardiac disorders | 12 of 112 | 4 of 103 |
| dyspnoea | Respiratory, thoracic and mediastinal disorders | 6 of 112 | 9 of 103 |
| dry mouth | Gastrointestinal disorders | 1 of 112 | 14 of 103 |
| headache | Nervous system disorders | 6 of 112 | 8 of 103 |
| palpitations | Cardiac disorders | 7 of 112 | 3 of 103 |
The registry’s serious adverse event table reports zero serious adverse events in the oxytocin group among 112 participants at risk and zero in the carbetocin group among 103 participants at risk. It also reports zero deaths in both groups. These are counts within the listed safety populations; the denominators differ from the primary biobank outcome counts.
A zero count in a trial does not prove that an event cannot occur, and it does not establish that the groups have identical safety profiles. In general, the information available about uncommon events depends on how many participants were observed, how events were defined and collected, and the duration of observation. The registry does not report enough detail to assess event definitions, ascertainment procedures, or follow-up for safety outcomes. The listed counts should therefore be read as the serious event and death figures recorded for this trial, not as evidence of no possible risk or as a comparison demonstrating equivalence.
13. What the Result Does, and Does Not, Mean
The primary result describes a comparison of plasma troponin I concentration at 8 hours in the analyzed biobank sample. The sponsor’s estimated median difference is 0 ng/L, and the confidence interval extends from -1.09 to 1.09 ng/L. This is an estimate of a group contrast with uncertainty, not a direct statement about every participant’s response. The same posted median in each arm is consistent with a point estimate centered at no difference, but it does not demonstrate that the complete outcome distributions are identical.
The result does not establish equivalence. An equivalence conclusion requires a prespecified range of differences considered acceptably small and an analysis designed to test whether the uncertainty lies within that range. No equivalence margin is reported in the registry record. The result also does not show that either drug does or does not cause clinically important myocardial effects. Troponin I is a biomarker outcome at a specified time, not a direct measure of clinical cardiac events or long-term outcomes.
The outcome data also should not be generalized beyond the people represented in the analysis without considering the trial population and missingness. The registry describes a biobank sample but does not report the complete analysis population, the reasons for differing denominators, or the handling of unavailable measurements. The study summary discusses possible relevance to delivery planning for women with heart disease, but the posted primary endpoint alone does not establish effects in that group or answer a clinical decision question.
In general, statistical interpretation separates the estimated effect, its uncertainty, and its clinical relevance. The posted estimate and interval describe the first two. The registry does not define a threshold for the third. Readers should therefore treat the finding as a result about the measured biomarker in the analyzed sample, not as a recommendation or a definitive statement about the comparative clinical effects of the drugs.
14. Why This Trial Matters Statistically
This trial illustrates why an endpoint’s statistical scale matters. The primary outcome is a biomarker summarized by medians and analyzed with median regression, while the secondary outcomes include both continuous and binary measurements. Each requires interpretation suited to what it measures. A common mistake is to treat a single point estimate or p value as a complete summary; the confidence interval, endpoint definition, and analyzed population are also essential to understanding the evidence.
The record also highlights the distinction between a randomized trial’s total enrollment and the participants contributing to a particular outcome analysis. The primary result comes from a biobank sample with fewer participants than the overall enrollment. Without an explanation of the differing denominators or a description of missing-data handling, readers cannot fully assess selection into the analysis or reproduce the primary result. Clear reporting of analysis populations and missingness is part of interpreting trial estimates, not merely an administrative detail.
Finally, the page separates sponsor-reported inference from secondary recalculations and planning illustrations. A model-based primary result, simple unadjusted secondary comparisons, and sample-size scenarios answer different questions. Planning figures based on observed effects are not observed power and do not recover the original design rationale. Likewise, unadjusted secondary results are less persuasive as a set when no multiplicity approach is reported. Keeping these distinctions visible helps readers avoid giving exploratory results the same weight as a prespecified primary analysis.
15. 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.
The primary outcome is a biomarker measured at 8 hours, and the registry does not report a clinical cardiac endpoint as the primary question. This limits the result to the measured troponin I comparison rather than a conclusion about symptoms, cardiac diagnoses, or later clinical outcomes. The study summary describes a rationale involving potential myocardial effects, but the endpoint itself cannot establish the clinical importance of any biomarker pattern.
The primary results are based on a biobank sample, and its posted arm counts are smaller than the overall enrollment. The registry does not explain the difference, define the analysis population, or report missing-data methods. It also does not give complete eligibility criteria or enough population detail to judge how well the analyzed sample represents the population discussed in the study rationale. These gaps constrain both interpretation and generalizability.
The sponsor’s primary analysis is described as median regression, but its model description is incomplete. The record does not report the full formula, covariates, baseline adjustment, or a complete explanation of the change analysis. This makes independent reproduction and assessment of model assumptions difficult. The lack of a reported equivalence margin also means the result cannot be used as a formal demonstration that the treatments are equivalent.
The registry lists secondary outcomes but does not report a multiplicity plan, and detailed results are unavailable for uterine tone grade. The secondary comparisons are therefore limited as confirmatory evidence. Finally, the registry does not report the original sample-size justification, interim analyses, or detailed safety ascertainment procedures. These are reporting limitations; they do not establish that such procedures were absent, only that they are not described in the registry record.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Carbetocin Myocardium Trial 2014 Part 2 — NCT03899961.
- Registry record last updated 2026-02-10; status last verified 2026-01.
- Results first posted 2025-03-25.
- 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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19. Record Summary
The registry record describes a completed, randomized, quadruple-masked, parallel-group phase 4 trial of oxytocin 2.5 U i.v. versus carbetocin 100 µg i.v., with enrollment of 240. The primary endpoint was plasma troponin I concentration at 8 hours in a biobank sample. The sponsor reported a median difference of 0 ng/L, with a 95% confidence interval from -1.09 to 1.09 ng/L and p = 0.05.
The posted secondary results include blood loss and side effects; further results for uterine tone grade are not reported in the registry record. The serious adverse event table records zero serious events and zero deaths in each group. Important details about the primary model, analysis populations, missing data, multiplicity, and original sample-size justification are not reported in the registry record. The findings should be interpreted as estimates for the posted outcomes and analyzed participants, not as a definitive conclusion about clinical cardiac effects.