Accuracy and Reliability of Fetal Heart Rate and Uterine Contraction Monitoring Method: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Accuracy and Reliability of Fetal Heart Rate and Uterine Contraction Monitoring Method (NCT01280357), a randomized na study. The primary outcome is The Mean Positive Percentage Agreement (PPA) for Fetal Heart Between Device 1 Monica AN24 & Device 2 Philips 50XM.

2. Clinical Question

In statistical terms, this is a device-comparison question: how closely did the fetal-heart measurements from the Monica AN24 agree with those from the Philips 50XM over the monitoring period? The study summary uses the language of determining equivalence, but the available primary-outcome record does not include a numerical result, an equivalence margin, or a reported equivalence analysis. The study’s stated purpose therefore should not be treated as evidence that equivalence was established.

3. Trial Design

The registry identifies the study as randomized, single masked, and using a single-group model. These design descriptors appear together with device-arm descriptions for the Philips 50XM and Monica AN24. The record does not explain how randomization was implemented or how the single-group model relates to the device-arm descriptions. It is therefore not possible to infer the allocation sequence, the unit randomized, or whether the devices were assigned in a particular order. Those details are not reported in the registry record.

The study summary describes a clinical investigation intended to determine equivalence of Monica AN24 monitoring to Philips 50XM monitoring for fetal heart rate and uterine contraction monitoring during labor. The intervention listings identify both devices, while the arm descriptions call Philips 50XM a CTG fetal monitor and Monica AN24 an EHG fetal monitor. The Philips description also gives a contingency: if confidence in Monica AN24 displayed data was lacking, the Monica monitor could be removed and monitoring continued with Philips 50XM. The frequency and consequences of this contingency are not reported.

The registry lists enrollment as 60 and status as completed. It gives a start date of 2010-02 and a primary completion date of 2010-06. The study was conducted in people in the first and second stages of labor, with monitoring described over a period between 35 minutes and 15 hours. The primary-outcome description refers to data from the remaining 34 participants and notes that participants contributed to different trial configurations. It does not explain the relationship between those data and the enrollment listing or why some enrolled participants are not included in that description.

The phase is listed as not applicable. The sponsor is Monica Healthcare Ltd. Although the stated aim is equivalence, the registry record does not report an equivalence margin, a detailed statistical analysis plan, the randomization procedure, or an explanation of the masking. These omissions limit how much can be concluded about the design beyond the descriptions recorded.

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.

Before assignment: For all participants if there is any issue or exclusion from monitoring with the Monica AN24, fetal monitoring should continue using the Philips 50xm device

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Of the remaining 34 participants in the clinical trials.The data was collected in the following manner. 31 participants were used in a FDA 6 way trial for Fetal Heart Rate (FHR)and Uterine Activity (UA) 2 participants were uesd in a 3 way trial for FHR 1 participant was used in a 3 way trial for UA Equates to 33 files for FHR \& 32 files for UA

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 The Mean Positive Percentage Agreement (PPA) for Fetal Heart Between Device 1 Monica AN24 & Device 2 Philips 50XM, measured over during labor and delivery the waveforms were measured for between 35 minutes and 15 hours during the first and second stage of labour.

The primary endpoint is the mean positive percentage agreement for fetal heart rate between Monica AN24 and Philips 50XM. The registry describes measuring fetal heart rate with both devices and comparing their waveforms to determine the percentage of time they were in agreement. Monitoring was described as taking place during labor and delivery, over periods between 35 minutes and 15 hours in the first and second stages of labor.

Positive percentage agreement is an agreement measure. In general, agreement measures describe the extent to which paired methods give matching or concordant observations under a defined comparison rule. They are useful when a study asks whether a new measurement method produces readings that correspond to those from a comparator. Agreement is not itself a measure of clinical benefit, and it does not by itself establish that either device is correct. Interpretation depends on how agreement is defined, how the waveform data are paired, and how repeated observations from the same participant are handled.

The endpoint is specified as a mean, with a 95% confidence interval as the dispersion measure. A confidence interval would ordinarily communicate the uncertainty around the estimated mean, but the registry record does not report the mean or the interval. It also does not give the operational rule for classifying waveform periods as agreeing, or the aggregation method used to obtain the mean. Consequently, the endpoint’s stated purpose is clear, but its numerical result and precision are not available in the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

This discussion explains general statistical concepts relevant to the outcomes and design descriptions. It does not reconstruct an analysis that the registry record does not report.

What does positive percentage agreement describe?

In general, positive percentage agreement summarizes how often two measurement methods are classified as agreeing on observations that meet a specified positive condition. Here, the primary outcome is described in terms of fetal-heart waveforms and the percentage of time they were in agreement. The registry does not state the detailed rule used to call waveform observations positive or agreeing. Without that rule, readers cannot determine exactly which features counted as a match, how borderline recordings were handled, or whether the measure was calculated across time points, waveform segments, or another unit.

Agreement and accuracy answer different questions. Agreement concerns correspondence between methods. Accuracy concerns closeness to a known or accepted truth. A comparison of two devices can show whether their outputs correspond under a scoring rule, but agreement alone cannot establish which device is closer to the true fetal-heart signal. The registry record does not identify a separate reference standard for the primary outcome. The comparator is Philips 50XM, so the endpoint should be read as agreement between devices rather than as a direct accuracy estimate against an independently established truth.

Why is the mean relevant?

The endpoint is defined as a mean of a continuous measure. In general, a mean gives an average across the observations included in its calculation. Its interpretation depends on what counts as an observation and how the observations are combined. If a participant contributes repeated waveform measurements, those measurements may be related rather than independent. A sound analysis ordinarily accounts for the structure of repeated data or first reduces observations according to a prespecified rule. The registry does not report the aggregation approach, so it is not possible to determine whether the reported target was a participant-level mean, a pooled summary, or another form of average.

Different participants may have contributed different monitoring durations; the described measurement periods range between 35 minutes and 15 hours. In general, a pooled calculation may give more influence to participants with more recorded time, while a participant-level average can give each participant comparable influence. Neither choice is automatically correct: the appropriate approach depends on the scientific question and the intended unit of inference. The registry record does not state which approach was used.

How should a confidence interval be read?

A confidence interval is a statistical description of uncertainty around an estimate, conditional on the analysis method and its assumptions. A narrower interval indicates greater precision under those assumptions, while a wider interval indicates less precision. The primary outcome specifies a 95% confidence interval, but no interval endpoints are reported. It is therefore not possible to judge precision or to use the interval to assess whether the results are compatible with a desired degree of agreement.

A confidence interval is not a guarantee that the estimate is correct, and it does not address sources of bias that the analysis fails to capture. For a device-comparison study, uncertainty may depend on the number of participants, the amount of usable recording, within-participant correlation, missing or uninterpretable signals, and the calculation method. The record does not give enough information to assess those components.

What would an equivalence analysis require?

In general, an equivalence analysis asks whether the difference between methods is sufficiently small according to a margin chosen before examining the results. The margin defines the largest difference still considered compatible with equivalence for the study’s purpose. The analysis then evaluates whether the uncertainty around the comparison excludes differences outside that acceptable range. Merely describing a study as designed to determine equivalence does not show that this criterion was specified or met.

The registry record does not state an equivalence margin, the specific statistical test or interval used for equivalence, or the numerical comparison. It also does not report a detailed statistical analysis plan. The mean positive percentage agreement is an agreement summary, but the record does not explain how that summary was connected to an equivalence decision. Readers should therefore distinguish the study’s stated aim from a demonstrated statistical conclusion.

What do the planning assumptions mean?

The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes planning for selected fractions of the observed effect. Such illustrations are conditional calculations: they indicate what sample size might be needed under stated assumptions if a target effect and analysis framework are accepted. They are not observed power, and they do not establish that the original study was designed with those assumptions.

The record does not give numerical planning results in the information available for interpretation, and it does not report the observed primary effect needed to assess an illustration based on that effect. The single-group model and randomized allocation descriptors also make it important not to assume that an equal-allocation, two-arm planning illustration exactly represents the implemented design. The actual sample-size justification and statistical plan are not reported in the registry record.

Why can repeated measurements matter?

In general, waveform observations collected from the same participant are likely to be related because they share characteristics of that participant, their labor, and the recording conditions. Treating every time point as independent can make an analysis appear more precise than it is. Methods that account for within-participant dependence, or a prespecified participant-level summary, can address that issue. The registry record does not describe the statistical handling of repeated measurements, so the adequacy of any such adjustment cannot be assessed.

The reported monitoring duration varies across the described recordings. Differences in recording duration may also affect the contribution of each participant to a pooled agreement statistic. The record does not state whether all available recording time was used, whether recordings were sampled, or whether a minimum recording length was required. These details are relevant to reproducibility and interpretation, but are not reported.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures, identifies the fetal-heart positive percentage agreement as primary, and names a secondary outcome concerning uterine-contraction positive percentage agreement. The details of the other outcome measures are not reported in the registry record. No analyses are listed. The record does not describe a statistical plan for controlling the chance of false-positive findings when more than one outcome or analysis is considered. It also does not say whether any outcomes were prioritized through a hierarchy or whether the secondary outcome was intended to support a separate conclusion.

Multiplicity matters in general because examining several outcomes or analysis choices can increase the chance of finding an apparently notable result by chance. Appropriate interpretation depends on the planned family of comparisons and any prespecified adjustment or testing sequence. Since neither the full analysis plan nor results are available, it is not possible to assess how multiplicity was handled. No inference should be made from an outcome being listed alone.

The endpoint description says the primary outcome population consisted of the remaining 34 participants and gives a breakdown of participant use across trial configurations. It does not define the analysis population, explain participant flow from the enrollment listing, or state how missing or unusable recordings were handled. The reasons data may have been unavailable, the extent of missingness, and any imputation or sensitivity analyses are not reported in the registry record.

In general, missing waveform data can affect an agreement estimate if the likelihood of missingness is related to device performance, recording quality, labor conditions, or participant characteristics. Analyses restricted to usable paired data may describe agreement among those recordings but may not represent all intended recordings. The record does not indicate whether paired data were required, how discordant or incomplete device recordings were treated, or whether the contingency to continue Philips monitoring after loss of confidence in Monica AN24 data affected inclusion. These details are necessary to assess the analysis population and potential selection effects.

11. Safety Results

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

Other (non-serious) adverse events

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

The adverse-event listing reports zero serious events and zero other events for each device group among the 60 participants listed at risk for that group. The registry does not list any terms for serious events. These are the recorded event counts in the posted safety information; they should not be interpreted as proof that no events occurred beyond what was captured or reported.

The deaths field is null for each group. A null entry is not the same as a reported count of zero. Deaths are therefore not reported in the registry record, rather than documented as absent in the posted figures. The record does not provide event definitions, collection procedures, follow-up details, or an explanation of how the group-specific risk denominators relate to the primary-outcome population.

Safety counts need context. In general, a lack of recorded events in a study does not by itself rule out an event risk, particularly when the study’s size, follow-up, and event ascertainment are not fully described. Here, the registry gives the recorded counts but does not provide additional information to assess completeness or duration of safety monitoring. These figures describe what the record reports; they do not establish a broader safety conclusion.

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

The record supports a limited description of the study’s purpose and planned comparison. It says Monica AN24 and Philips 50XM were assessed for fetal-heart and uterine-contraction monitoring during labor, and identifies mean positive percentage agreement for fetal heart rate as the primary outcome. It also specifies that the endpoint was intended to be accompanied by a 95% confidence interval.

What the record does not provide is the central evidence needed to evaluate that comparison: the observed primary-outcome estimate, its confidence interval, or a reported analysis. Without those results, readers cannot determine the extent of agreement, the precision of an estimate, or whether the comparison met a statistical criterion. The stated intention to determine equivalence should not be read as a finding of equivalence. The equivalence margin and the analysis needed to evaluate such a claim are not reported in the registry record.

Even if an agreement estimate were available, it would describe correspondence according to the study’s measurement and scoring procedures. In general, agreement between devices is not the same as proof that either device measures the true signal without error. The record does not describe an independent reference standard or the detailed agreement rule, so the meaning and limits of the endpoint cannot be fully assessed.

The registry’s enrollment listing is 60, while its primary-outcome description refers to the remaining 34 participants and provides details of participant use in trial configurations. It does not explain how the analysis population was formed. The safety listing records zero serious and other events in each group, but deaths are null and therefore not reported. These entries should be read as registry information, not as complete evidence about every possible outcome or event.

In short, the record describes an intended device-agreement investigation but does not report the primary result. It cannot establish that Monica AN24 was equivalent to Philips 50XM, that the devices differed, or that the observed agreement was clinically adequate. Those conclusions would require results and methods that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically interesting because it concerns measurement agreement rather than a comparison of treatment outcomes. For a device comparison, it is important to distinguish correspondence between methods from accuracy against a known truth. The primary endpoint is explicitly an agreement measure for fetal-heart waveforms, so its definition, unit of analysis, and handling of repeated recordings are central to interpretation.

The record also illustrates why a stated research objective and an analyzed result are different things. The study summary says the investigation was designed to determine equivalence, but the record does not include a numerical primary result, an equivalence margin, or a reported equivalence analysis. Equivalence is a statistical claim requiring a defined acceptable range and evidence that uncertainty excludes differences beyond that range. A study title or purpose alone cannot establish that claim.

Data structure is another important issue. Monitoring periods are described as lasting between 35 minutes and 15 hours, and the primary-outcome population description refers to participants used in different trial configurations. In general, variable recording duration and repeated observations can influence how an average agreement statistic should be calculated. The choice between participant-level and pooled summaries, and the handling of dependence within participants, can affect both the estimate and its uncertainty. Those methods are not reported.

Finally, the record shows the importance of separating enrollment, analysis populations, and safety reporting. The enrollment listing and the primary-outcome population description do not have a documented relationship, and the safety listing has null death fields rather than reported zero counts. These are not reasons to infer an unreported result; they identify limits on what can be interpreted. The study’s statistical value can be discussed as a design question, but the registry information does not permit a substantive conclusion about observed device agreement.

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 main limitation is the absence of reported primary-outcome results. Although the endpoint specifies a mean and a 95% confidence interval, neither is available in the registry record. This prevents assessment of effect size, precision, and any statistical conclusion about the device comparison.

The record does not report an equivalence margin or the analysis used to test equivalence. It therefore does not establish how a numerical agreement result would have been judged against the stated objective. The detailed agreement-scoring rule, reference standard, and statistical method for calculating the mean are also not reported. These omissions restrict both reproducibility and substantive interpretation.

The design descriptors are difficult to reconcile fully: allocation is listed as randomized, masking as single, and the model as single group, while device-arm descriptions are also recorded. The randomization procedure, unit of allocation, masking details, and relation between these descriptors are not reported. The record also does not state how the option to discontinue Monica AN24 monitoring and continue with Philips 50XM was used or how such cases entered the primary analysis.

The registry lists enrollment as 60, while the primary-outcome description refers to the remaining 34 participants and notes different trial configurations. The flow from enrollment to endpoint analysis, reasons for non-inclusion, amount of missing or unusable data, and handling of incomplete paired waveforms are not reported. Nor is the method for dealing with variable monitoring duration and repeated observations described.

Finally, the record lists three outcome measures but no analyses. The full statistical plan, multiplicity handling, and detailed safety ascertainment are not reported. These limitations make it inappropriate to infer unreported methods, reasons for participant selection, or conclusions about equivalence, accuracy, or safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Accuracy and Reliability of Fetal Heart Rate and Uterine Contraction Monitoring Method — NCT01280357.
• Registry record last updated 2013-03-21; status last verified 2013-03.
• Results first posted 2013-03-21.
• 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 describes a completed clinical investigation intended to compare Monica AN24 with Philips 50XM for fetal-heart and uterine-contraction monitoring during labor. It lists randomized allocation, single masking, a single-group model, and enrollment of 60. The primary outcome is mean positive percentage agreement for fetal heart rate, with a 95% confidence interval specified.

The primary-outcome description refers to the remaining 34 participants and gives details of use across trial configurations. Monitoring was described during the first and second stages of labor, over periods between 35 minutes and 15 hours. A secondary outcome concerns positive percentage agreement for uterine contractions.

The registry record does not report the primary estimate, confidence interval, or analyses. It also does not report an equivalence margin, detailed statistical plan, or the relationship between enrollment and the primary-outcome population. Safety entries report zero serious and other events in each group; deaths are not reported. The record supports a description of the intended comparison, but not a conclusion about the observed agreement or equivalence.