Presence of a Companion During Performance of Neuraxial Labor Analgesia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Presence of a Companion During Performance of Neuraxial Labor Analgesia (NCT02982213), a randomized na study. The primary outcome is Maternal Satisfaction and the Presence of a Companion During the Placement of Epidural Catheter for Labor Analgesia..

2. Clinical Question

The study’s stated purpose is to evaluate whether maternal anxiety is improved when a parturient gets her choice about companion presence during placement. The brief summary also describes interest in possible differences by ethnicity, health literacy, catastrophizing, and the relationship of the support person to the parturient. Those aims are not the same as the registered primary outcome, which is maternal satisfaction. Anxiety is listed among the study conditions, and the secondary outcomes include a question about anxiety measured with the STAI questionnaire.

The registry describes two conditions during the procedure: companion present and no companion present. It does not report enough detail to explain how a participant’s preference was incorporated into assignment to those conditions. The primary question should therefore be read as a question about satisfaction in this trial’s companion-presence comparison, not as a complete answer to whether honoring a preference changes anxiety or satisfaction.

3. Trial Design

The registry describes a randomized, parallel-group study with no masking. The intervention is labeled “Companion Present,” and the arm descriptions distinguish a companion-present condition from a no-companion condition during epidural catheter placement. The registry lists enrollment of 150. In the adverse-event entries, each group has 75 participants listed as at risk; these entries describe the safety counts and do not supply outcome results for satisfaction or anxiety.

The study is marked completed. The recorded start date is 2016-12-01 and the recorded primary completion date is 2017-04-01. The phase is listed as NA. Northwestern University is identified as the sponsor. The listed conditions are anxiety, pain, and health knowledge, attitudes, and practice.

The brief summary says the study focuses on parturients having their first child with their current partner. It describes the purpose as examining maternal anxiety in relation to a parturient getting her choice about companion presence during labor epidural catheter placement. The registry also lists possible interests in ethnicity, health literacy assessed by the Newest Vital Sign questionnaire, catastrophizing assessed by the Pain Catastrophizing Scale, and the support person’s relationship to the parturient.

Randomization can help make groups comparable on average, but that general property does not establish that allocation was concealed or that all possible sources of bias were controlled in a particular trial. The method used to generate the allocation sequence, the process for concealing assignments, and any stratification or blocking are not reported in the registry record. The record states that masking was none; it does not describe which people, if any, were aware of assignment beyond that designation. These omissions limit how specifically the assignment process can be assessed.

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.

Population: In the companion not in the room group, 73 subjects received the intervention and 70 completed follow up. In the companion in the room group, 75 completed demographic data, 73 subjects received intervention and 74 completed follow up.

6. Primary Endpoint

The registry lists the primary outcome as Maternal Satisfaction and the Presence of a Companion During the Placement of Epidural Catheter for Labor Analgesia., measured over Average 12 hours, up to 24 hours after epidural placement.

The registered primary outcome is maternal satisfaction after epidural catheter placement for labor analgesia in relation to companion presence. The measure is described as a five-point Likert scale with the categories Highly Dissatisfied, Dissatisfied, Neutral, Satisfied, and Highly Satisfied. The stated timeframe is an average of 12 hours, up to 24 hours after epidural placement.

Satisfaction is a patient-reported outcome: it captures the participant’s evaluation of the experience, rather than a procedural measure or an observer’s rating. That makes it a relevant way to describe how participants felt about care in this setting. As a general statistical point, Likert responses are ordered categories. Their order conveys whether a response is more or less favorable, but the spacing between adjacent categories is not necessarily equal. Analyses can therefore differ in whether they preserve the separate categories, treat the scale as ordered, or summarize responses in another way.

The registry record does not report how the categories were analyzed, whether a summary score was used, or whether there were missing responses. It also does not provide the number of participants in each satisfaction category by group. The primary outcome’s measurement and timeframe are described, but the posted information does not provide a numerical estimate of the difference between groups or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does randomization contribute?

Randomization assigns participants to study conditions using a chance-based process. As a general statistical principle, this can reduce systematic differences between groups at the time of assignment, including differences that are not measured. It does not guarantee that groups will be identical, particularly on characteristics that occur infrequently, and it does not correct problems arising after assignment, such as missing outcome data or departures from the planned intervention.

This study is recorded as randomized, with a parallel model and no masking. The record does not describe the sequence-generation method, allocation concealment, or the handling of participants who did not follow their assigned condition. It also does not report an analysis plan or identify the analysis population. These details matter because they help readers assess whether the reported estimate, if available, would preserve the benefits of randomization. In their absence, the design can be described, but its implementation cannot be fully evaluated.

How should the satisfaction scale be understood?

The primary outcome uses five ordered satisfaction categories, ranging from Highly Dissatisfied through Neutral to Highly Satisfied. As a general point, categorical responses can be summarized in multiple ways. Reporting each category retains the response pattern. Combining categories can make an analysis easier to communicate but loses detail, and a numerical score assumes a particular interpretation of the scale. A statistical model for ordered categories uses their rank information without necessarily assuming that the distance between neighboring categories is equal.

The registry record describes the scale but does not report the analysis method, the category counts, or a prespecified definition of a favorable response. It also does not say whether the analysis would compare the full distribution, a selected summary, or a dichotomized outcome. Those choices affect what an estimate means. Without the analysis details and results, there is no basis for selecting one interpretation over another.

What would an estimate and confidence interval tell a reader?

In general, an effect estimate would quantify the observed contrast between the companion-present and no-companion groups using a stated scale or model. A confidence interval describes statistical uncertainty around that estimate under the assumptions of the analysis. A wide interval indicates limited precision; a narrow interval indicates greater precision. Neither an estimate nor its interval proves that a causal explanation is correct, and interpretation also depends on the design, outcome measurement, and completeness of follow-up.

The registry record does not report a primary-outcome estimate, confidence interval, or p-value. It therefore does not allow a reader to assess the direction, magnitude, or precision of the satisfaction comparison. A non-significant test, if one had been reported, would not by itself demonstrate that the groups were equivalent. Conversely, statistical significance alone would not establish that a difference was important to participants. These are general principles; the record does not permit them to be applied to an observed satisfaction result.

How should the planning illustration be read?

The described sample-size illustration uses a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It is characterized as planning based on a fraction of the observed effect, rather than as a calculation documenting the trial’s original design. The registry record does not report the trial’s own sample-size justification or the numerical planning results. No particular number of participants needed for a future study can therefore be stated from the record.

As a general matter, a sample-size calculation asks how much information a planned study would need under specified assumptions about the effect, variability or event frequency, allocation, and statistical error rates. Changing those assumptions changes the planning result. A planning illustration based on an estimated effect is especially dependent on that estimate: if the effect is imprecisely estimated, the illustration inherits that uncertainty. Such calculations describe hypothetical planning conditions; they are not observed power and do not establish the probability that the completed trial detected an effect.

What role do outcome counts play?

For binary outcomes, group counts can be used to form a difference or ratio, depending on the chosen measure. In general, the uncertainty of such comparisons depends on the number of observed events as well as the number of participants contributing data. When events are sparse or absent, estimates can be unstable or difficult to define with conventional methods. These general considerations do not produce an efficacy estimate for this trial: the listed adverse-event counts are safety entries, while the registry does not report the primary satisfaction categories or a binary primary outcome.

For the satisfaction endpoint, the response categories are ordered rather than a simple event/no-event outcome. Reducing them to a binary event would require a defined threshold, which the record does not report. The endpoint should not be treated as though such a threshold had been selected. The absence of a reported analytic specification makes it impossible to determine what statistical model, test, or effect measure the investigators used.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary satisfaction outcome and several secondary questions, including anxiety measured with the STAI questionnaire, perceived procedural difficulty reported by the resident physician, future preference for companion presence, and recommendation of care based on the companion’s experience. The brief summary also describes interest in subgroup patterns involving ethnicity, health literacy, catastrophizing, and the relationship of the support person to the parturient. Considering multiple outcomes or subgroups raises a general multiplicity issue: as the number of statistical comparisons increases, so can the chance of at least one apparently notable result arising by chance.

The registry record does not report a multiplicity adjustment, a hierarchy for testing secondary outcomes, a prespecified subgroup analysis plan, or which outcomes were included in any confirmatory analysis. The hypotheses described in the brief summary should not be treated as documented statistical testing procedures. Without results and analysis details, it is not possible to assess whether multiplicity was addressed or how any subgroup findings were interpreted.

The record does not report the amount or pattern of missing primary or secondary outcome data, reasons for missingness, or a method for handling missing responses. It also does not identify whether analyses were based on all randomized participants, participants who received the assigned condition, or another population. These details are important because exclusion or imputation choices can affect estimates and their uncertainty. The record’s enrollment and safety counts do not establish how many participants contributed usable satisfaction or anxiety outcomes.

11. 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 5% reporting threshold.

The adverse-event entries list the No Companion group and Companion Present group separately. For each group, 75 participants are listed as at risk. The entries record 0 serious adverse events, 0 other adverse events, and 0 deaths in each group. These are the recorded counts; they do not provide a comparison of maternal satisfaction or anxiety.

A zero count means that no events of that type are recorded in the corresponding entry. As a general statistical principle, zero observed events do not prove that the underlying risk is zero. The ability to detect uncommon events depends on the amount of observation and the way events are defined, collected, and recorded. The registry record does not report event definitions, the surveillance period for adverse events, or details of event ascertainment. It is therefore not possible to determine how completely these entries capture all relevant events.

The safety counts should be interpreted as descriptive registry information, not as evidence that the study established equivalence between groups or that either condition is risk-free. The record does not report an inferential safety analysis, an uncertainty interval, or a formal comparison.

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

The registry record establishes that a randomized, parallel-group trial compared companion presence with no companion during epidural catheter placement for labor analgesia. It identifies maternal satisfaction on a five-point Likert scale as the primary outcome and gives the assessment timeframe as an average of 12 hours, up to 24 hours after placement. It also describes anxiety and several other questions as secondary interests.

That information explains what the study set out to examine, but it does not reveal what participants reported. No group-specific satisfaction results, anxiety results, effect estimate, confidence interval, or significance test are reported in the registry information. The direction and size of any difference between groups, and the precision with which it was estimated, are therefore unknown from this record. The stated hypothesis about possible subgroup effects is not a finding.

Likewise, the safety entries document zero recorded serious events, other events, and deaths in both groups, but do not establish that event risk is absent or that the conditions are equally safe. The record does not provide enough information about adverse-event collection to assess the completeness of those counts.

As a general statistical distinction, absence of a reported result is not the same as a result showing no effect. It is also not proof of equivalence or proof that the study was unable to detect a difference. Those conclusions require outcome data and an analysis that are not reported in the registry record. The most defensible reading is limited: the trial design and intended measurements are described, but the primary comparison and its uncertainty cannot be evaluated from the posted information.

13. Why This Trial Matters Statistically

This trial raises a statistically useful distinction between a study’s stated motivation and its registered primary endpoint. The brief summary emphasizes maternal anxiety and whether a parturient gets her choice about companion presence. The primary outcome, however, is maternal satisfaction measured using ordered response categories. These are related aspects of the experience, but they answer different questions and should not be treated as interchangeable outcomes.

The design also highlights the importance of specifying what a group comparison represents. The registry describes companion-present and no-companion conditions, while its purpose statement refers to getting one’s choice. A comparison of the two conditions and an evaluation of the effect of honoring preference are not necessarily the same estimand. The record does not report enough detail about preference and allocation to determine precisely how that distinction was handled analytically.

There is further statistical interest in the stated possibility of subgroup patterns. Subgroup questions can be clinically and scientifically relevant, but their interpretation depends on prespecification, adequate information within subgroups, and careful attention to multiplicity. The registry record describes potential factors of interest but does not report a subgroup analysis plan or results.

Finally, the record illustrates why transparent results matter. A completed randomized design and a clearly described outcome do not, on their own, tell readers whether groups differed, how large a difference may have been, or how uncertain it was. Reporting outcome distributions, analysis methods, and uncertainty would be necessary to evaluate the primary question statistically. In their absence, conclusions should remain focused on the trial’s design and the information that is actually recorded.

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.

The principal limitation for interpreting this trial from the registry record is the absence of numerical results for the primary satisfaction outcome. The record describes the five response categories and assessment timeframe but does not report category counts, an effect estimate, an uncertainty interval, or a statistical test. It also does not report the numerical results for the listed anxiety and other secondary outcomes.

The distinction between the study’s purpose and its primary endpoint creates an interpretive limitation. The stated purpose centers on anxiety and getting a choice about companion presence, whereas the primary outcome is satisfaction. The record does not report how preference was measured in relation to assignment, or whether the primary analysis was intended to estimate an effect of companion presence, of honoring preference, or another contrast.

Important design and analysis details are not reported in the registry record. These include the allocation-sequence method, allocation concealment, eligibility criteria in full, the statistical analysis plan, the analysis population, handling of missing outcomes, and multiplicity procedures. The record also does not specify how the five satisfaction categories would be analyzed. Without these details, it is difficult to assess risk of bias or understand what a reported comparison would represent.

The safety entries record no events but do not describe event definitions, collection methods, or the period of safety monitoring. They cannot establish absence of risk. Finally, the stated interests in subgroup differences do not come with reported subgroup estimates or a documented testing plan, so no subgroup conclusion can be drawn from the available record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Presence of a Companion During Performance of Neuraxial Labor Analgesia — NCT02982213.
• Registry record last updated 2021-11-12; status last verified 2021-11.
• Results first posted 2021-01-26.
• 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.

18. Record Summary

The registry identifies NCT02982213 as a completed, randomized, unmasked, parallel-group study titled “Presence of a Companion During Performance of Neuraxial Labor Analgesia.” Northwestern University is the sponsor. The recorded start date is 2016-12-01 and primary completion date is 2017-04-01. Enrollment is listed as 150, and phase is listed as NA.

The study compares a companion being present with no companion during labor epidural catheter placement. The registered primary outcome is maternal satisfaction on a five-point scale, assessed on average 12 hours and up to 24 hours after placement. Secondary questions include anxiety measured with the STAI, procedural difficulty, future preference, and recommendation of care.

The registry record does not report numerical primary or secondary outcome results, statistical comparisons, or details of missing-data and multiplicity procedures. Safety entries list zero serious events, zero other events, and zero deaths in each group.