Acupuncture With Manual and Electrical Stimulation to Reduce Labour Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Acupuncture With Manual and Electrical Stimulation to Reduce Labour Pain (NCT01197950), a randomized na study. The primary outcome is Use of Epidural Analgesia.

2. Clinical Question

3. Trial Design

The registry identifies this as a randomized controlled trial with a factorial model. It lists three groups: manual acupuncture, electro-acupuncture, and standard care. The manual acupuncture group received manual stimulation; the electro-acupuncture group received electrical and manual stimulation; and standard care was described as no acupuncture. Although the model is labelled factorial, the factors, their levels, and the intended factorial contrasts are not reported in the registry record. The record therefore does not establish how the three listed groups map to a factorial structure.

The allocation is recorded as randomized and masking as none. Randomization can reduce systematic differences between groups at entry when implemented successfully, but details of sequence generation, allocation concealment, and implementation are not reported in the registry record. With no masking, participants and study personnel were not recorded as masked. The record does not say whether outcome assessors were masked.

Enrollment is reported as 303. The posted group sizes are 99.0 for manual acupuncture, 103.0 for electro-acupuncture, and 101.0 for standard care. The study is marked completed; its recorded start is 2008-10 and its primary completion is 2011-08. The phase is listed as NA. The sponsor is University of Skövde.

The record lists one outcome measure and no posted analyses. It does not report the planned allocation ratio, the trial protocol, the rationale for the sample size, an analysis population, or the statistical plan. These omissions limit assessment of how the implemented trial compared with its 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 Use of Epidural Analgesia, measured over From start of treatment until birth.

The primary endpoint is titled “Use of Epidural Analgesia.” It is measured in participants, with a timeframe from the start of treatment until birth. The description calls it the frequency of epidural analgesia. In practical terms, the endpoint concerns whether participants used epidural analgesia during the stated period, reported as a count rather than as a pain rating.

An endpoint based on use of analgesia can describe a treatment decision or care event during labour. It is not interchangeable with a direct measure of pain intensity: a participant’s pain experience, preferences, access to analgesia, and clinical circumstances are not separately represented by the count. The registry does not explain how epidural use was ascertained, whether use was defined as any use or by another criterion, or whether timing or duration was considered.

The posted primary outcome values are 99.0 for manual acupuncture, 103.0 for electro-acupuncture, and 101.0 for standard care. These are the same as the corresponding posted group sizes. The comparison summaries likewise report event proportions of 1.0 in each compared group. The registry does not explain this correspondence or provide participant-level outcome data that would clarify it. Accordingly, the endpoint can be described as recorded in the registry, but the completeness and meaning of the posted counts cannot be independently assessed from this record alone.

7. Results Posted in the Registry

• Manual Acupuncture: 100.0% (99/99) versus 100.0% (101/101) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.
• Electro Acupuncture: 100.0% (103/103) versus 100.0% (101/101) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.

8. Statistical Interpretation

9. Statistical Methods Explained

What does a risk difference describe?

General explanation: For a binary outcome, a risk is the proportion of participants in a group who experience the event. A risk difference compares two such proportions by subtracting the reference-group risk from the other group’s risk. A value of zero indicates equal observed proportions. Positive or negative values indicate the direction of the difference according to the order used for the subtraction. In this trial, the registry labels the measure as a risk difference and reports 0.0 for both acupuncture-versus-standard-care comparisons.

The displayed proportions are 1.0 in both groups for each comparison. The endpoint count in each group is also reported as equal to its group size. Those posted values account for the reported zero differences, but the record does not clarify why every participant is counted as having the endpoint. The comparison metric can be described, but the underlying outcome coding cannot be verified using the information in the registry record.

How should a confidence interval be understood?

General explanation: A confidence interval expresses uncertainty about an estimated effect under a specified statistical procedure and its assumptions. It is not a range containing a known fixed percentage of individual outcomes, and it does not assign a probability to the truth of a particular effect after the data have been observed. Its interpretation depends on the method used and the quality of the data being analysed.

The registry reports lower and upper limits of 0.0 and 0.0 for both risk differences. It does not report the confidence level, interval method, or analysis details behind those limits. The limits should therefore be treated as posted summaries, not as independently verified evidence that the true difference is known without uncertainty.

What does the p-value contribute?

General explanation: A p-value describes how incompatible the observed data, or more extreme data, are with a specified null hypothesis under a statistical model. It does not measure effect size, clinical importance, or the probability that the null hypothesis is true. Interpretation depends on the hypothesis, test, data, and analysis choices.

The posted p-value is 1.0 for each comparison. The registry does not identify the test used, whether it was one-sided or two-sided, or the hypothesis and analysis plan specified before the results were known. The p-values should be read as part of the posted summaries, not as a complete account of the analysis.

What design and planning details are available?

The record labels the trial randomized, unmasked, and factorial, but it does not report the randomization method, concealment, or the structure of the factorial design. It lists three groups and does not post an interaction analysis. An interaction would address whether the effect of one factor depends on another; whether such a question was planned is not reported in the registry record.

The record also describes a planning illustration based on a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. These assumptions describe a planning exercise, not the trial’s own design justification. No protocol-based sample-size rationale is reported in the registry record. Such planning values, where displayed, are not observed power and do not change the interpretation of the trial’s results.

Over-dispersion is a general issue when observed variation exceeds what a statistical model assumes. It can make standard errors too small and intervals too narrow if it is ignored. The posted primary outcome is a binary count, and no dispersion estimate or model for over-dispersion is reported. There is consequently no basis to say whether an over-dispersion adjustment was relevant or used. More broadly, the registry does not provide enough analysis detail to reproduce the comparison or assess its assumptions. The posted estimates and p-values can be reported, but they cannot substitute for a prespecified statistical plan and a transparent account of the analysis.

10. Confidence Intervals and Precision

The reported risk-difference interval for manual acupuncture versus standard care runs from 0.0 to 0.0. The interval for electro-acupuncture versus standard care has the same reported limits. These are intervals with no displayed width. The registry does not identify the confidence level or the procedure used to calculate them, so their statistical properties cannot be assessed from the record.

General explanation: A confidence interval is commonly used to show the range of effect estimates compatible with data under a statistical method and its assumptions. Its width is informative about precision only when the method and data are appropriate. A narrow interval is not automatically reliable if the outcome data, model, or analysis have not been validated.

Here, the event proportions are reported as 1.0 in all groups, and the event counts match the group sizes. That pattern is directly relevant to precision: the apparent absence of variation in the posted binary outcome may lead to boundary estimates or special behavior under some methods. The record does not say whether the interval procedure accounts for this situation. The identical endpoints should not be read as proof that uncertainty is absent.

The record also does not give participant-level observations, missing-outcome counts, or an analysis-population definition. Without those details, readers cannot determine whether the posted group denominators represent everyone enrolled, everyone randomized, or a subset with outcome data. The interval summaries therefore describe what the registry posts, while leaving important questions about their calculation and data basis unresolved.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no posted secondary outcomes. It provides comparisons of manual acupuncture with standard care and electro-acupuncture with standard care. A multiplicity plan for these comparisons is not reported in the registry record. Without such a plan, it is not possible to determine whether the reported p-values were adjusted for multiple comparisons or whether one comparison was designated as primary for inference. The record does not report an adjustment method.

The analysis count is recorded as 0, despite the presence of comparison summaries. The registry does not explain this distinction or provide a fuller analysis report. No statistical analysis plan, protocol, or description of the test used is posted. The factorial label also raises questions about possible factor effects and interactions, but the planned contrasts and any factorial analysis are not reported in the registry record.

Missing-data handling is not described. The record does not report whether any participants lacked an endpoint value, how such outcomes were handled, or whether sensitivity analyses were conducted. The posted group sizes alone do not establish the number analysed for the primary endpoint. It also does not define an intention-to-treat, per-protocol, or other analysis population, or describe exclusions after randomization.

These omissions matter because the reported event counts equal the posted group sizes in all three arms. The registry does not clarify whether that equality reflects complete outcome ascertainment, the coding of the endpoint, or another reporting convention. Without missing-data and population definitions, readers cannot judge how the counts relate to the randomized participants or how robust the comparisons may be. These details are not reported in the registry record.

12. 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.

Most frequent non-serious adverse event terms

The adverse-event fields report zero serious adverse events among 99 participants at risk in manual acupuncture, among 103 in electro-acupuncture, and among 101 in standard care. The fields for other adverse events also report zero affected participants in each group. No serious adverse-event terms are listed.

The death fields, however, list 99 deaths for manual acupuncture, 103 for electro-acupuncture, and 101 for standard care. These counts match the respective numbers reported at risk. They cannot be reconciled with the zero serious-event and other-event counts using the information in the registry record. The record does not explain what the death field represents, how the values were entered, or whether the counts are intended to describe deaths during the trial.

It would therefore be inappropriate to interpret the adverse-event entries as evidence of either no deaths or deaths among every participant. The death values require clarification against the underlying record before they can support a safety interpretation. The registry also does not report definitions, observation periods, ascertainment procedures, or a narrative explaining these fields. The posted adverse-event data do not provide a clear, internally interpretable account of safety.

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

The registry records a randomized comparison of manual acupuncture, electro-acupuncture, and standard care for a trial whose stated purpose was to evaluate acupuncture in relation to labour pain. Its posted primary endpoint is epidural analgesia from the start of treatment until birth. The comparison summaries report equal event proportions and a risk difference of 0.0 for each acupuncture group versus standard care, with p-values of 1.0.

Those results do not show that pain was the same across groups. Epidural use is a care event, not a direct pain-intensity measure, and no pain-scale result is posted. Nor do the summaries demonstrate that either approach changes pain or epidural use in a broader population. The record does not report an equivalence objective or margin, so a zero estimated difference cannot be interpreted as proof of equivalence.

The primary endpoint counts match the group sizes, and the registry does not explain this feature. The posted interval limits are also 0.0 to 0.0, without a reported method. These issues mean that the numerical summaries should not be taken as a fully validated estimate with established precision. The record does not provide the protocol, statistical analysis plan, participant-level outcomes, missing-data account, or analysis-population definition needed to resolve the uncertainties.

Safety interpretation is also limited. Although the serious and other adverse-event fields list zero affected participants, the death fields list counts matching the group sizes. The registry does not clarify this discrepancy, so those entries cannot support a clear conclusion about deaths or overall safety.

The defensible reading is therefore narrow: the registry posts equal proportions for its epidural-use endpoint across the three groups, while leaving important questions about outcome coding, analysis, precision, and safety unresolved. These results should not be extended beyond what the posted record documents.

14. Why This Trial Matters Statistically

This trial is statistically notable because the primary endpoint is presented as a binary participant count and every group’s event count matches its reported group size. The comparison summaries consequently show event proportions of 1.0 throughout and risk differences of 0.0. That pattern is easy to summarize numerically but difficult to evaluate without knowing how the endpoint was defined, collected, and coded.

The example illustrates a general principle: an estimate is only as interpretable as the data and analysis that generated it. A p-value of 1.0 and an interval from 0.0 to 0.0 may look definitive, but they do not resolve questions about the underlying data or the statistical method. Transparent outcome definitions, analysis-population descriptions, missing-data handling, and interval procedures are central to evaluating apparent precision.

The registry’s factorial designation also makes design reporting important. The record lists three groups but does not explain the factors, their structure, or any planned interaction analysis. A clear design description is needed to understand which contrasts address the trial’s intended questions and how those comparisons relate to one another.

Finally, the adverse-event entries show why safety fields need contextual interpretation. Zero serious and other events appear alongside death counts that match group sizes. Without an explanation, neither a reassuring nor an alarming interpretation is justified. Resolving such inconsistencies is part of statistical reporting, not a minor administrative detail.

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 record contains limited detail about eligibility, participant characteristics, treatment delivery, and standard care. It does not describe recruitment procedures, baseline balance, the randomization method, allocation concealment, or outcome-assessment procedures. Masking is recorded as none, but the record does not clarify whether outcome assessors were masked.

The primary endpoint is described as the frequency of epidural analgesia over a period from treatment start until birth, but the operational definition and collection method are not reported. The event counts equal the corresponding group sizes, and the registry does not explain why. This limits confidence in interpreting the endpoint as a conventional count of participants who experienced an event.

The statistical documentation is sparse. The registry does not report the analysis method, confidence-interval procedure, analysis population, missing-data approach, prespecified contrasts, multiplicity plan, or protocol-based sample-size justification. Although the trial is labelled factorial, the factors and intended factorial analysis are not described. No secondary outcomes are posted, and no analyses are listed in the analysis count.

The adverse-event record is also difficult to interpret: serious and other adverse-event counts are listed as zero, while death counts match the numbers at risk. The registry does not reconcile these fields. These limitations are specific to the information available in the record and prevent a complete assessment of both the primary result and safety reporting.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Acupuncture With Manual and Electrical Stimulation to Reduce Labour Pain — NCT01197950.
• Registry record last updated 2022-09-21; status last verified 2022-09.
• Results first posted 2022-06-06.
• 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.

19. Record Summary

NCT01197950 is a completed randomized, unmasked trial sponsored by University of Skövde, with a factorial model recorded in the registry. Enrollment is 303. The three listed groups are manual acupuncture, electro-acupuncture, and standard care; the study began in 2008-10, and primary completion is recorded as 2011-08.

The primary endpoint is use of epidural analgesia from treatment start until birth. The registry reports group values matching group sizes and risk differences of 0.0 versus standard care, with p-values of 1.0 and interval limits of 0.0 to 0.0. The record does not explain the endpoint-count pattern or the interval method. Safety fields list zero serious and other adverse events but death counts matching the group sizes, without clarification. Further details about the statistical plan, missing data, and analysis populations are not reported in the registry record.