Continuous Glucose Monitoring in Pregnant Women Undergoing Betamethasone Therapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Continuous Glucose Monitoring in Pregnant Women Undergoing Betamethasone Therapy (NCT01165775), a registered phase not stated study. The primary outcome is Percentage Time Spent Above Glucose Thresholds (>110;>144;>180) 24-48 Hours Post Betamethasone Treatment.

2. Clinical Question

3. Trial Design

This completed study is registered as NCT01165775 and is sponsored by Stanford University. Its stated title is Continuous Glucose Monitoring in Pregnant Women Undergoing Betamethasone Therapy. The record lists Pregnancy Complications as the condition. The study began in 2010-07, and primary completion was recorded as 2014-06.

The arm description concerns patients with threatened preterm labor who received betamethasone and monitored glucose using the Dexcom Seven Plus Continuous Glucose Monitoring System. The registry does not describe a like-for-like control group, and allocation is not stated. It explicitly characterizes the study as not a randomized comparison. Accordingly, the available description supports interpretation of monitoring in the described group, not a randomized contrast between alternative treatments or monitoring strategies.

Seventeen women were enrolled at the time of betamethasone administration. The primary-outcome description says data were available for 15 patients. The specified monitoring period was 24 hours, occurring 24-48 hours after betamethasone treatment. The primary measure was the percentage of time above the listed glucose thresholds; its parameter was the mean, with standard deviation as the dispersion measure.

The registry lists neonatal hypoglycemia as a secondary outcome. It records 2 outcome measures and 1 analysis, but does not provide the analysis details or the results for the primary or secondary outcomes. The record also does not report a protocol-level sample-size justification, study design rationale, or a fuller account of follow-up and participant selection. Those omissions limit how completely the design and analysis can be reconstructed.

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

Analysis population for the primary outcome, as defined in the registry: Seventeen women were enrolled at the time of betamethasone administration and data were available for 15 patients.

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: Women receiving clinically indicated betamethasone between 24 and 34 weeks of pregnancy. Data are available for 15 of 17 participants.

6. Primary Endpoint

The registry lists the primary outcome as Percentage Time Spent Above Glucose Thresholds (>110;>144;>180) 24-48 Hours Post Betamethasone Treatment, measured over 24-48 hours post betamethasone treatment.

The primary endpoint is the percentage of time spent above glucose thresholds >110, >144, and >180 during a 24-hour monitoring period 24-48 hours after betamethasone treatment. It is a continuous measure summarized as a mean, with standard deviation specified to describe dispersion. The record’s description frames the endpoint as a way to characterize maternal glucose levels in the period after administration.

Expressing glucose exposure as time above thresholds captures duration as well as whether readings cross a threshold. In general, this kind of summary can help describe how glucose readings are distributed over a defined monitoring window. It does not by itself explain why readings were elevated, establish a causal effect of betamethasone, or show whether a particular glucose pattern leads to a clinical outcome.

The registry record does not report the observed mean percentages or standard deviations for any of the listed thresholds. It also does not report confidence intervals, individual participant values, or the outcome’s result text. The endpoint’s planned definition is therefore available, but its magnitude and precision cannot be assessed from the registry record. Neonatal hypoglycemia is listed as a secondary outcome, but its results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a continuous measure summarized by a mean and standard deviation. The measure is the percentage of time spent above each listed glucose threshold during the specified monitoring window. The record does not report a model, a hypothesis test, an interval estimate, or a detailed statistical analysis plan. The explanations below describe general statistical concepts and should not be read as claims about analyses performed in this study.

What does a mean describe?

In general, a mean summarizes the central level of a continuous measurement across the observations included in an analysis. For this endpoint, it would describe the average participant-level percentage of monitoring time above a threshold, provided the participant-level percentages were the analysis units. The registry names the mean as the parameter but does not explain the exact analysis unit or detail how readings were converted into participant-level percentages.

A group mean can be useful for a concise summary, but it does not show whether participant values cluster closely or whether some values are notably different from others. It also does not describe the shape of the distribution. Individual values or additional summaries can sometimes reveal patterns that a mean alone obscures, but those are not reported for this endpoint in the registry record.

What does the standard deviation describe?

In general, a standard deviation describes the spread of observed values around their mean. A larger standard deviation indicates greater dispersion among the values used in the summary; it is not the same quantity as the uncertainty in the estimated mean. The registry specifies standard deviation as the dispersion measure, but does not report its numerical value for the primary outcome.

A standard deviation is most straightforward to interpret alongside the corresponding mean and with knowledge of the distribution and unit of analysis. It does not, by itself, communicate how precisely the population mean has been estimated. A confidence interval is a different kind of summary: in general, it gives a range of values compatible with the data and the interval procedure’s assumptions. No confidence interval is reported for the primary endpoint in the registry record.

What does percentage of time above a threshold represent?

In general, a time-above-threshold measure condenses a series of glucose readings into a duration-based summary for a defined interval. It can distinguish a brief threshold crossing from a pattern that remains above the threshold for more of the monitoring period. The interpretation depends on the threshold, the monitoring window, the data captured, and how missing or unusable readings are treated. The record names a continuous monitoring device and specifies a 24-hour window 24-48 hours after treatment, but it does not report technical details such as data completeness rules or the calculation procedure.

The listed thresholds define related but distinct summaries. A participant could have different percentages of time above each threshold. The registry record does not report those percentages, how the analyses accounted for their relationship, or whether any threshold was designated as more important than another for interpretation.

Why does over-dispersion matter?

In general, over-dispersion refers to observed variation that is larger than a statistical model expects. It can make standard errors too small and confidence intervals too narrow when a model assumes less variation than the data contain. This concept may matter in analyses of clustered or repeated measurements, because measurements from the same person are often related rather than independent. The registry identifies continuous monitoring, but does not report a model for the repeated readings, an over-dispersion assessment, or any adjustment for within-person dependence. It would be inappropriate to infer that such methods were or were not used.

What can be inferred from the analysis description?

The record lists 1 analysis, but does not explain its method, population, or assumptions. It does not report a statistical test or a result for the primary outcome. A reader therefore cannot determine from the registry record whether the analysis was purely descriptive or included additional inferential procedures. The mean and standard deviation specify a summary and dispersion measure, not a complete analysis plan.

The record also describes planning illustrations based on a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the detectable effect expressed as a fraction of the observed effect. These are planning assumptions, not evidence that the trial itself used a two-arm randomized design or had that statistical plan. The study description does not identify a like-for-like control comparison. Any sample-size figures based on such assumptions are planning illustrations, not observed power, and do not establish what the enrolled study could detect. The registry record does not report a protocol sample-size justification or a power calculation used to determine enrollment.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome names several glucose thresholds, and the registry also lists neonatal hypoglycemia as a secondary outcome. Considering multiple endpoints can raise a multiplicity question: when several statistical claims are tested, the chance of at least one apparently notable result can increase. General approaches include prespecifying a primary comparison, adjusting inference, or treating analyses as descriptive. The registry record does not report whether any multiplicity strategy was planned or used, whether all listed outcomes were analyzed, or how results across thresholds were interpreted.

Missing-data information is limited. The record says 17 women were enrolled at betamethasone administration and that data were available for 15 patients for the primary outcome. It does not state why data were unavailable for the remaining enrolled participants, whether the amount of missing monitoring data varied by participant or threshold, or whether missing readings were excluded, imputed, or handled by another method. The assumptions behind any missing-data approach are therefore not reported in the registry record.

The analysis population is not described. The record does not say whether the primary analysis included every enrolled participant with any data, only participants with complete monitoring, or another defined group. It also does not report whether participants were excluded after enrollment or how the outcome was calculated when a monitoring record was incomplete. No intention-to-treat or per-protocol analysis population is identified.

The registry lists 2 outcome measures and 1 analysis, but does not provide the analysis description or enough detail to determine how those outcomes relate to the reported analysis. These omissions prevent a full assessment of multiplicity, missingness, and analysis-population choices.

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 5% reporting threshold.

For the group titled Threatened Pre Term Labor Patients, the registry records 17 participants at risk and 0 affected for serious adverse events. It also records 17 at risk and 0 affected for other adverse events. These are counts for the categories as entered in the registry; they do not provide detail about event ascertainment, observation duration, or individual event histories.

A zero count means that no affected participants were recorded in the stated category in this registry entry. It should not be interpreted as proof that the underlying risk was absent. In general, safety counts describe what was observed and recorded within a study’s size, follow-up, and reporting process; they cannot rule out events that were not observed or not reported. The death field is not reported in the registry record. No serious adverse event terms are listed.

These safety entries are separate from the glucose endpoint and the listed secondary outcome of neonatal hypoglycemia. They do not supply the missing results for either outcome and do not establish a comparison with another group. The registry record does not provide a broader safety analysis or additional context for interpreting the event counts.

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

The registry record describes a study intended to characterize maternal glucose levels after betamethasone treatment using continuous glucose monitoring. It specifies the primary measurement, thresholds, and monitoring window, and reports that 17 women were enrolled, with primary-outcome data available for 15 patients. Those details explain what was planned and how much primary-outcome data the record says were available.

The record does not report the observed percentages of time above the glucose thresholds, their means, or their standard deviations. It therefore does not establish the size, direction, or variability of the glucose-time measurements. It also does not report a result for neonatal hypoglycemia, the listed secondary outcome. The available information cannot be used to say what those outcomes showed.

The study description does not identify a randomized control comparison. A descriptive summary from the monitored group, even if its value were reported, would not alone show that betamethasone caused a particular glucose pattern. Other influences on glucose could not be separated from treatment effects through a randomized contrast that is not described in this record. The record’s stated objective is to clarify glucose levels after administration, but the posted information does not establish a causal effect.

The serious and other adverse event entries report zero affected participants among 17 at risk in each category. These counts are limited to the categories recorded and should not be treated as evidence that no adverse events could occur. The record does not report the death field or list serious adverse event terms.

In general, the distinction between a study’s question and its findings is important: an endpoint definition indicates what investigators intended to measure, while reported results are needed to assess the observed data. In this case, the registry record contains the former but not the numerical primary or secondary outcome results. It supports a description of the study and its reporting limits, not a conclusion about treatment effects or clinical outcomes.

13. Why This Trial Matters Statistically

This study is statistically interesting because its primary outcome translates continuous glucose monitoring into a time-above-threshold summary. Such a measure retains information about duration above a cutoff, rather than reducing the monitoring period to a single glucose reading. Interpreting it still requires careful attention to the thresholds, time window, unit of analysis, and handling of incomplete recordings.

The record also illustrates the difference between enrollment and outcome availability. Seventeen women were enrolled, while data were available for 15 patients for the primary outcome. Without a reason for that difference or a missing-data method, readers cannot assess how the availability of monitoring data may affect the reported summary. Transparent accounting of analysis populations and missingness is important when evaluating descriptive estimates as well as treatment comparisons.

The design description matters for statistical interpretation. The record does not describe a randomized control comparison, so the stated objective of understanding glucose after betamethasone should not be confused with evidence of a causal treatment effect. A clearly defined endpoint can be useful for measurement, but causal conclusions depend on design and analysis features that are not reported.

Finally, the record separates endpoint definitions from outcome reporting. It specifies a mean and standard deviation for a continuous primary measure, yet does not report their values. It lists neonatal hypoglycemia as a secondary outcome without reporting its findings. This makes the registry entry useful for understanding what was intended to be measured, while also showing why complete numerical results and analysis details are needed to evaluate the evidence.

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 for interpreting this trial is the absence of numerical primary outcome results in the registry record. Although the endpoint definition and summary measures are stated, there is no reported mean percentage, standard deviation, or uncertainty estimate for time above any listed glucose threshold. The secondary outcome, neonatal hypoglycemia, is listed without a reported result as well.

The outcome-data statement is incomplete for assessing missingness. The record reports enrollment of 17 women and data availability for 15 patients, but does not explain the unavailable data, specify whether participants had incomplete monitoring, or describe a method for handling missing observations. It also does not identify the analysis population or give participant-level outcome summaries.

The design details limit causal interpretation. The registry says allocation was not stated and that the study was not a randomized comparison; the described arm does not establish a like-for-like control. The record does not report a detailed protocol, sample-size justification, statistical analysis plan, or methods for handling multiple thresholds and outcomes. It also does not explain how repeated monitoring readings were processed or whether within-participant dependence was addressed.

The safety information is similarly limited to the reported counts: zero affected participants among 17 at risk in each of the serious and other adverse event categories. The death field is not reported in the registry record, and no serious adverse event terms are listed. These entries do not provide detailed event follow-up or a basis for comparing safety with another group.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Continuous Glucose Monitoring in Pregnant Women Undergoing Betamethasone Therapy — NCT01165775.
• Registry record last updated 2016-09-16; status last verified 2016-07.
• Results first posted 2016-09-16.
• 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

NCT01165775 is a completed study sponsored by Stanford University, with a start date of 2010-07 and primary completion recorded as 2014-06. It concerns pregnant women receiving betamethasone for threatened preterm labor and monitoring glucose with the Dexcom Seven Plus Continuous Glucose Monitoring System.

The primary endpoint is mean percentage of time above glucose thresholds >110, >144, and >180 during a 24-hour monitoring period 24-48 hours after treatment, with standard deviation specified as the dispersion measure. Seventeen women were enrolled, and data were available for 15 patients for the primary outcome. Neonatal hypoglycemia is listed as a secondary outcome.

The registry record does not report numerical primary or secondary outcome results, the analysis method, or details of missing-data handling. It records 0 affected participants among 17 at risk for both serious and other adverse events. The study is not described as a randomized comparison, and allocation is not stated.