Postpartum Management of Gestational Hypertensive Disorders Using Furosemide: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Postpartum Management of Gestational Hypertensive Disorders Using Furosemide (NCT04343235), a randomized phase 4 study. The primary outcome is Change of Dose for Antihypertensive Therapy.

2. Clinical Question

The study’s broader rationale, as stated in the registry, was to assess whether adding furosemide could affect the need to add or increase antihypertensive medication and could be associated with blood-pressure measures, hospital stay, or readmission. Those aims are distinct from the primary endpoint: the primary result concerns a change in labetalol dose, not every aspect of blood-pressure control or postpartum care.

The registry describes a randomized controlled study without masking. The posted primary outcome counts are 3 participants in the labetalol-plus-furosemide group and 0 in the labetalol-only group. The registry reports a Fisher exact test p-value of 0.21 for the group comparison. These figures describe the observed trial data; they do not, by themselves, establish a treatment effect or explain why the study ended.

3. Trial Design

This was a Phase 4, randomized, parallel-group trial registered as NCT04343235. The listed sponsor was Wright State University. The study began on 2020-05-01, and the primary completion date was 2022-06-30. Its status is terminated. The reason for termination is not reported in the registry record.

The registry summary describes a prospective, randomized 1:1 controlled study of postpartum patients with a gestational hypertensive diagnosis. The two arms were labetalol plus furosemide and labetalol only. The reported enrollment was 13. The posted primary outcome groups contain 6 participants in the combination arm and 7 in the labetalol-only arm. These enrollment and outcome-group figures are the registry entries, but the record does not explain whether all enrolled participants contributed to each analysis or how participants were handled after randomization.

Masking is listed as none. This means the record does not describe a blinded comparison; it does not establish what participants or study staff knew at each stage beyond the registered masking designation. Details about allocation concealment, the process used to generate the random sequence, and the roles of staff in assigning treatment are not reported in the registry record.

The primary outcome was the number of participants requiring a change in labetalol dose to control blood pressure from randomization until hospital discharge, up to 7 days. Secondary outcomes listed in the record include changes in systolic blood pressure, diastolic blood pressure, and mean arterial pressure; hospital length of stay; breastfeeding status; and hospital readmission. The record lists 7 outcome measures and 6 posted secondary outcomes. The full measurement definitions and results for those secondary outcomes are not included in the registry record for this analysis.

The parallel design assigns participants to a treatment group and compares outcomes between groups. Randomization is intended to reduce systematic differences in baseline characteristics, but it cannot guarantee balance in a small study. The registry record does not report the baseline characteristics, detailed eligibility criteria, treatment duration beyond the stated outcome window, or protocol deviations. Those omissions limit assessment of how closely the enrolled groups and observed treatment experience followed the intended design.

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

Reasons for not completing this period:

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.

6. Primary Endpoint

The registry lists the primary outcome as Change of Dose for Antihypertensive Therapy, measured over Change in dose of hypertensive therapy from randomization until hospital discharge (up to 7 days).

The primary endpoint counts participants who required a change in the dose of labetalol to control blood pressure. Its stated observation window runs from randomization until hospital discharge, up to 7 days. The registry identifies the unit as participants and describes the outcome as a count, rather than as an average change in blood pressure or a continuous dose measurement.

This endpoint addresses a practical aspect of the study’s stated question: whether the initial labetalol regimen needed adjustment during the hospital stay. A count-based outcome can be useful when the research question concerns whether an event occurred for each participant. It does not capture how large a dose change was, when it occurred, or the clinical circumstances surrounding it. Those details are not reported in the registry record.

The posted results record 3 participants with a dose change in the labetalol-plus-furosemide arm and 0 in the labetalol-only arm. These are observed counts for the registered outcome. They do not measure all dimensions of blood-pressure control, and the endpoint should not be treated as interchangeable with the secondary measures of systolic, diastolic, or mean arterial pressure.

The endpoint also ends at hospital discharge, with the record specifying a maximum window of 7 days. It therefore does not directly summarize dose changes after discharge. The precise criteria used to decide that a dose change was required, and whether any changes could include dose decreases as well as increases, are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary at the participant level: each participant either had a labetalol dose change during the stated window or did not. The registry presents counts of participants with the outcome, alongside the number in each group. A comparison of binary outcomes asks whether the observed distribution of outcome status differs between treatment groups. The registry reports Fisher’s exact test for this comparison.

Why use Fisher’s exact test?

Fisher’s exact test is a method for testing association in a contingency table of categorical data. It calculates the probability of possible tables under a null model of no association, conditional on the observed margins. The exact calculation can be useful when the data are sparse, because it does not rely on the large-sample approximation used by some other tests. Here, the reported outcome counts are small, and one group has no participants recorded with the event. An exact test is therefore a recognizable approach to the registered type of comparison.

The test addresses whether the observed pattern is unusual under its null model; it does not directly estimate the size of a treatment effect. The registry reports p = 0.21 but does not report a confidence interval or a numerical effect estimate. A p-value is not a measure of the probability that a result occurred by chance, and it is not a measure of the probability that a treatment is effective. Its interpretation depends on the null model, the test procedure, and the data included in the analysis.

What does sparse data mean for interpretation?

When a binary outcome is recorded for few participants, the observed counts contain limited information about the range of outcomes that might occur in the wider population. Individual observations can have a noticeable influence on a group’s pattern. A test can still be calculated, but the resulting inference may be imprecise. Exact testing addresses the calibration of a test under its assumptions; it does not create additional information or compensate for limited enrollment.

In general, an effect estimate paired with a confidence interval helps readers assess both direction and precision. A confidence interval represents a range of values compatible with the data and the estimation procedure, under its assumptions. It is not a guarantee that the true value lies within the interval. No confidence interval for the primary comparison is reported in the registry record, so readers cannot use a reported interval to evaluate the range of plausible effect sizes.

How should the reported p-value be read?

The p-value is 0.21 for the Fisher exact comparison. The registry’s planning description refers to a two-sided significance level of 0.05 for planning illustrations. It does not state that this was the prespecified decision threshold for the sponsor’s primary analysis. A p-value and a significance threshold answer different questions: the p-value summarizes compatibility with a null model, while a threshold is a decision rule chosen for a particular analysis. Statistical significance, even when assessed against a stated threshold, does not measure clinical importance.

The posted result does not demonstrate equivalence between treatment groups. An equivalence conclusion requires a design and analysis that define an acceptable range of differences and assess whether the estimate is sufficiently precise to exclude effects outside that range. Such a margin and analysis are not reported in the registry record. Nor does the p-value establish that a difference exists; the limited counts and absence of a reported interval leave substantial uncertainty about the effect’s magnitude.

What can planning illustrations tell readers?

The registry describes sample-size planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It states that the effect to detect is a specified fraction of the observed effect, and that non-time-to-event planning outputs are expressed as participants per arm. These are planning assumptions, not results from the randomized comparison. A planning illustration does not indicate that the trial had a particular observed power, and it should not be treated as evidence that the study was adequately sized.

Using an observed effect as the basis for a planning exercise can make the result sensitive to the instability of a small study. The description does not report a separate design effect or an independently justified target effect. The protocol’s sample-size justification is not reported in the registry record. No planning value is because a numerical planning result is not included in the registry entries relevant to this explanation.

What does randomization contribute?

Random assignment is intended to make treatment groups comparable in expectation with respect to measured and unmeasured baseline factors. In a small realized sample, chance imbalances can remain. The registry identifies the study as randomized and parallel, but details of sequence generation and allocation concealment are not reported in the registry record. The study is listed as unmasked. These design features matter when considering whether observed group differences could be influenced by knowledge of assigned treatment or by implementation of the study.

The posted analysis is a group comparison for a count-based binary endpoint. The record does not report an adjusted model, covariate adjustment, a confidence interval, or a complete statistical analysis plan. It also does not report how the investigators treated missing observations, protocol deviations, or participants who may not have completed the outcome window. Without these details, readers cannot determine whether the analysis followed an intention-to-treat approach or another analysis population.

These methods explain what the reported test can and cannot address. Fisher’s exact test evaluates the observed categorical pattern under its null model. It does not resolve questions about missing data, endpoint definition, generalizability, clinical importance, or the reliability of results from a small terminated study. Those questions require additional reporting beyond a test statistic and p-value.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Labetalol + Furosemide", "Labetalol Only")
n      <- c(6, 7)
events <- c(3, 0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Labetalol + Furosemide  6  3  50.0  11.8  88.2  18.8  81.2  18.4  81.6
ARM  Labetalol Only  7  0  0.0  0.0  41.0  0.0  35.4  0.3  36.9

11. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary comparison as a Fisher exact test with p = 0.21. It does not report a numerical effect estimate or a confidence interval for that comparison. The registry’s recalculation information indicates that a two-arm recalculated result was not estimable for this binary endpoint, so there is no independent recalculated estimate or interval to compare with the sponsor’s test result.

The distinction matters: a recalculation from posted summary statistics can check a simple unadjusted analysis when those statistics support it, but it cannot replace the sponsor’s analysis or recover details absent from the record. In this case, the sponsor’s reported Fisher exact test is the available inferential result. No discrepancy between a sponsor result and a recalculation is flagged in the registry entries.

The reported p-value should still be read with the outcome counts and the limits of the record in mind. It does not convey the size or precision of an effect, and no confidence interval is reported. The exact analysis details beyond the named test, including a fuller statistical plan and analysis population, are not reported in the registry record.

12. Multiplicity, Missing Data and Analysis Populations

The record lists the primary endpoint and several secondary outcomes, including changes in systolic blood pressure, mean arterial pressure, and diastolic blood pressure, hospital length of stay, breastfeeding status, and hospital readmission. It lists 7 outcome measures and 6 posted secondary outcomes. The relationship between the registered outcome count and the posted secondary outcome list is not explained in the registry record.

When a study examines multiple outcomes, the chance of finding an apparently unusual result somewhere among them can increase. Statistical approaches to multiplicity can include adjusting significance thresholds or defining a hierarchy of outcomes in advance. The registry record does not report whether any multiplicity adjustment, outcome hierarchy, or other strategy was used. It also does not report results for the secondary outcomes in the registry record considered for this analysis, so their estimates and uncertainty cannot be assessed.

Missing-data procedures are not reported in the registry record. The primary outcome counts are posted for the two groups, but the record does not explain whether all randomized participants had outcome data, how any missing outcome values were handled, or whether participants were excluded from the analysis. The enrollment figure and the group sizes shown for the primary outcome do not, on their own, establish the analysis population or the handling of withdrawals and protocol deviations.

The registry does not report whether the primary analysis followed an intention-to-treat approach, a per-protocol approach, or another defined population. It does not provide details of the statistical analysis plan, including any planned covariate adjustment, interim analyses, or rules for handling deviations. These details are important because analysis choices can affect both interpretation and the comparability of reported outcomes. In their absence, the posted p-value should be treated as the reported test result, not as a complete account of the study’s analysis strategy.

13. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports no serious adverse events and no deaths in either posted group. For serious adverse events, the recorded at-risk counts are 6 in the labetalol-plus-furosemide group and 7 in the labetalol-only group; the number affected is 0 in each group. The other adverse-event counts are also recorded as 0 for both groups, with the same group-specific at-risk counts.

These figures describe what was recorded in this trial. They do not establish that adverse events cannot occur, or that the treatments have equal safety. With limited enrollment, an event not observed in the study may still occur in a broader population or under different observation conditions. The registry does not report an adverse-event collection window, the methods used to solicit or verify events, or further details about event severity beyond the serious and other categories presented.

The record lists no top serious-event terms. The absence of listed terms is consistent with the posted zero serious-event counts, but does not add information about events outside the trial’s reporting procedures. Safety findings should therefore be understood as limited observations from the registered groups, not as a comprehensive estimate of risk.

14. What the Result Does, and Does Not, Mean

The result establishes what was recorded for the primary endpoint in this trial: 3 participants in the labetalol-plus-furosemide group required a change in labetalol dose, while 0 participants in the labetalol-only group did. The registry reports a Fisher exact test p-value of 0.21. These observations describe the enrolled groups over the outcome window from randomization until hospital discharge, up to 7 days.

The data do not establish that adding furosemide caused a difference in dose changes. A randomized design is intended to support a causal comparison, but the small enrollment, the limits of the posted analysis information, and the absence of a reported effect estimate and confidence interval restrict what can be concluded. The result also does not show that the groups were equivalent or that a potentially important difference is absent.

The primary endpoint concerns whether labetalol dose changed; it is not a direct summary of blood-pressure levels, hospital length of stay, breastfeeding status, or readmission. Those outcomes appear in the registry as secondary measures, but their results are not reported in the registry record used. The primary result therefore cannot answer the full set of aims described in the study summary.

The registry status is terminated, but the reason is not reported in the registry record. Termination alone does not explain the observed counts, indicate the quality of the study, or establish whether the termination was related to efficacy, safety, recruitment, or another issue. Any such explanation would be speculation.

In general, a clinical trial result is most informative when the outcome definition, analysis population, effect estimate, uncertainty, missing-data procedures, and full outcome reporting are available. Here, the registry provides the endpoint counts and the named exact test, but several of those interpretive details are not reported. The result is best viewed as a limited description of this trial’s primary outcome rather than a definitive answer about postpartum management of gestational hypertensive disorders.

15. Why This Trial Matters Statistically

This trial illustrates how the type of outcome and the size of the dataset shape statistical interpretation. The primary endpoint is a count of participants with a dose change, making the comparison categorical rather than a comparison of average blood-pressure values. The registry reports Fisher’s exact test, a method suited to categorical data and capable of handling sparse patterns without relying on a large-sample approximation.

Choosing an exact test does not make a small study highly informative. The posted group sizes are 6 and 7, and the event counts are 3 and 0. Such data can support a formal test, but they offer limited information for estimating how large or precise a group difference may be. The registry does not report a confidence interval or numerical effect estimate, leaving readers without a direct measure of uncertainty around the effect.

The study also highlights the importance of distinguishing a trial’s broad clinical aims from its primary endpoint. The registry summary discusses blood pressure, medication changes, hospital stay, and readmission, while the primary endpoint specifically concerns a change in labetalol dose. These measures are related to the study’s subject but answer different questions. A primary outcome result should not be taken as a result for every secondary aim.

Finally, the registry includes planning assumptions based on the observed effect. Such illustrations are not observed power and do not substitute for a design justification made before data collection. In a small terminated study, transparent reporting of the analysis population, missing-data handling, endpoint definitions, and uncertainty is particularly important. Their absence limits both interpretation of the primary finding and the ability to plan future research from it.

16. 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 registry reports enrollment of 13 and primary outcome groups of 6 and 7, so the available primary comparison is based on a small number of observations. The reported event counts are 3 in the combination group and 0 in the labetalol-only group. This limited information makes the observed pattern sensitive to individual outcomes and constrains the precision that can be inferred from the record. No confidence interval or numerical effect estimate is reported for the primary comparison.

The study is listed as unmasked. The registry does not report whether any outcome assessment involved subjective judgment, or what safeguards were used to reduce the influence of knowledge of assigned treatment. Details of random-sequence generation and allocation concealment are also not reported. These omissions prevent a fuller assessment of the conduct of randomization and the potential for bias.

The primary endpoint is defined as a need for a labetalol dose change to control blood pressure, but operational criteria for that decision are not reported. The registry does not describe the magnitude or direction of dose changes, or the clinical context in which they occurred. Its outcome window ends at hospital discharge, up to 7 days, and does not summarize dose adjustments after discharge.

Missing-data handling, the analysis population, protocol deviations, and the statistical analysis plan are not reported in the registry record. The study is terminated, but its reason is not reported. The registry lists secondary outcomes, but their results are not available in the registry record considered for this analysis, and multiplicity procedures are not reported. These limitations restrict assessment of the study’s broader aims, the completeness of outcome reporting, and the generalizability of its primary finding.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Postpartum Management of Gestational Hypertensive Disorders Using Furosemide — NCT04343235.
• Registry record last updated 2023-10-23; status last verified 2023-09.
• Results first posted 2023-10-23.
• 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.

20. Record Summary

NCT04343235 is a Phase 4 randomized, parallel-group trial of postpartum management for gestational hypertensive disorders. The listed sponsor is Wright State University. The study compared labetalol plus furosemide with labetalol only, was unmasked, and is registered as terminated. The registry reports enrollment of 13, a start date of 2020-05-01, and a primary completion date of 2022-06-30. The reason for termination is not reported in the registry record.

The primary endpoint counted participants requiring a change in labetalol dose between randomization and hospital discharge, up to 7 days. The posted counts were 3 in the combination group and 0 in the labetalol-only group; the registry reports a Fisher exact test p-value of 0.21. No confidence interval or numerical effect estimate is reported. Secondary outcomes include blood-pressure measures, hospital length of stay, breastfeeding status, and hospital readmission. Their results and the details of missing-data and multiplicity procedures are not reported in the registry record.