The MOTHER (Mobile Technologies to Help Enhancing Regular Physical Activity) Trial for Pregnant Women: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The MOTHER (Mobile Technologies to Help Enhancing Regular Physical Activity) Trial for Pregnant Women (NCT01461707), a randomized na study. The primary outcome is Physical Activity Monitor Measured Steps.

2. Clinical Question

The registry background identifies physical inactivity during pregnancy and excessive gestational weight gain as reasons for studying activity support. It also states that regular physical activity is recommended to maintain healthy weight gain, while many pregnant women are sedentary. Those statements describe the motivation for the study; they are not results of the trial. The study is explicitly characterized as a pilot intended to estimate potential efficacy. A pilot estimate can be informative for planning further research, but the record does not provide the result needed to judge the estimated effect in this case.

3. Trial Design

The MOTHER trial is registered as a randomized, single-masked, parallel-group pilot study. It compares a mobile phone-based physical activity program plus an activity monitor with an activity monitor alone. Random allocation and a parallel-group structure mean that the intervention groups were intended to be compared over the same study period, rather than each participant serving as their own control. The registry record does not say who was masked, what procedures were used to maintain masking, or whether masking was successful.

The record lists an enrollment of 30 and identifies the study population as physically inactive pregnant women. The trial status is completed. The recorded start is 2012-10, and the primary completion is 2014-05. The registry lists the sponsor as the University of California, San Francisco. The phase is listed as NA, and the condition is physical activity. These registration details describe the study record; they do not provide participant-level information or establish how many participants contributed data to a particular analysis.

The intervention group was assigned a mobile phone-based physical activity program and an activity monitor. The comparator group was assigned an activity monitor. The registry identifies both interventions as behavioral. It does not report the content or delivery schedule of the phone-based program, the monitor model, any adherence measures, or whether the intervention changed during the study.

The primary outcome is described as a continuous measure, with the parameter identified as a mean and dispersion as a standard deviation. It concerns change in weekly mean steps per day, measured by a physical activity monitor at 12 weeks. The registry record flags the primary outcome as having several categories or time points and does not reduce it to a single comparison. It lists the 7-Day Physical Activity Recall as a secondary outcome. Although the record lists two outcome measures, it does not give a corresponding set of primary and secondary result estimates in the information available for interpretation.

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 Physical Activity Monitor Measured Steps, measured over 12 weeks.

The listed primary endpoint is physical activity monitor-measured steps. The registry describes it as change in weekly mean steps per day, with assessment at 12 weeks. Steps are a continuous measure of activity: the endpoint summarizes movement captured by a monitor rather than a participant's report of activity. The registry identifies the endpoint's summary parameter as a mean and its dispersion as a standard deviation, but does not supply a single result for the intended comparison.

Using a monitor gives the study an objective activity measure, which can complement reported activity. The registry also lists the 7-Day Physical Activity Recall as a secondary outcome; recall-based measures rely on participants' reports, whereas the primary measure is described as monitor-measured. This distinction can matter because different measurement approaches may capture activity differently. The record does not describe monitor wear requirements, data-processing rules, or how missing monitor observations were handled.

A change measure is intended to represent how the activity measure shifts over the study period. For an intervention comparison, interpretation depends on the difference in change between groups, not merely on whether one group changes from its own starting point. The registry record does not provide a single baseline-to-follow-up comparison, group means, standard deviations, confidence interval, or test result for the primary endpoint. Consequently, the endpoint's definition can be explained, but the amount of change and its precision cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The design and outcome definitions tell readers what comparison the study intended to make. They do not, by themselves, provide an estimate of the intervention effect. For the MOTHER trial, the registry identifies random allocation to a mobile phone-based physical activity program plus an activity monitor or an activity monitor alone. It identifies a continuous primary measure and describes the target as change in weekly mean steps per day at 12 weeks. The registry record does not provide one primary comparison, so general statistical principles can be explained, but no trial-specific effect estimate or uncertainty can be interpreted.

What does random allocation contribute?

In general, random allocation aims to make the intervention groups comparable at the point of assignment, including with respect to factors that may affect the outcome. It supports interpretation of a between-group contrast as an intervention comparison, provided the trial is conducted and analyzed appropriately. Randomization does not guarantee that the groups will be identical in a small study, and it does not resolve problems such as missing outcome measurements or deviations from assigned treatment. The registry identifies the trial as randomized but does not report the allocation sequence method, concealment procedures, or analysis details.

Why distinguish a change from a group comparison?

A change score describes movement from a participant's or group's starting value to a later value. In a randomized parallel-group trial, the intervention question is generally addressed by comparing outcomes between assigned groups, using an analysis suited to the outcome and design. A change within one group is not the same as evidence that its change differs from the comparator's. The registry's endpoint wording refers to change, but it does not report the group-level values or a single between-group contrast. The amount and direction of any difference therefore remain unreported in the registry record.

What do means and standard deviations describe?

For a continuous measure, a mean describes the average value in a group. A standard deviation describes the spread of individual values around that average. These summaries answer different questions: the mean locates the center of the observed values, while the standard deviation conveys variability among participants. A standard deviation is not a confidence interval and does not directly express how precisely a treatment effect has been estimated. The registry specifies mean and standard deviation for the primary measure but does not provide the corresponding group summaries for a single comparison.

What would a confidence interval add?

In general, a confidence interval describes the statistical uncertainty around an estimated effect under the assumptions of the analysis. It can show which effect sizes are reasonably compatible with the data and model, rather than reducing interpretation to whether a test crosses a threshold. A narrow interval indicates greater precision than a wide interval, though clinical importance still requires context. No confidence interval for the primary between-group comparison is reported in the registry record. It is therefore not possible to judge the range of effects compatible with the trial's posted primary outcome data.

How should significance testing be read?

A significance test evaluates how compatible the data are with a specified null hypothesis under a statistical model. A p-value is not the probability that the null hypothesis is true, nor does it measure the size or practical importance of an effect. Its interpretation depends on the analysis, assumptions, and the number of comparisons considered. The registry record does not report a single primary test result or a statistical analysis plan. No claim about statistical significance can be made from the outcome description alone.

What do the planning assumptions mean?

The registry's sample-size assumptions describe an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. The assumptions also distinguish participants per arm for non-time-to-event outcomes from total events for time-to-event illustrations. These are planning conventions, not observed trial outcomes and not evidence of observed power. A planning illustration depends on the effect estimate chosen and on its assumptions. The registry record does not provide a sample-size justification for this pilot study, and the primary outcome is not presented as one comparison from which to interpret an observed effect.

Over-dispersion is a general issue when observed variation is greater than a statistical model expects. If it is ignored, uncertainty can be understated and tests can appear more decisive than warranted. Appropriate modeling should reflect the outcome distribution and study design. The registry record does not report an over-dispersion assessment or identify a model for the primary outcome, so this general consideration cannot be attributed to the trial's analysis.

Finally, analysis choices must align with the outcome structure. The registry flags the primary measure as having several categories or time points, rather than a single comparison. Multiple outcomes or repeated assessments can raise questions about which contrast is primary and how multiplicity is addressed. The record does not report a hierarchy, adjustment, or a model that answers those questions. Thus, the available details support a description of the intended endpoint and design, but not a reconstruction or verification of the statistical analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and identifies the 7-Day Physical Activity Recall as a secondary outcome. The primary outcome description is flagged as having several categories or time points and is not reduced to one comparison. When a study examines multiple outcomes, time points, or categories, general statistical practice calls for clarity about which comparison is primary and how additional analyses are interpreted. Without that specification, the chance of encountering a seemingly notable result across many tests can be difficult to assess. The registry record does not report a multiplicity adjustment, testing hierarchy, or plan for handling the several primary outcome categories or time points.

The registry lists zero analysis entries. This does not establish that no analysis was conducted; it means the registry record does not provide analyses for interpretation. It also does not include an analysis plan specifying the model, covariates, handling of repeated observations, or the contrast used to estimate the primary effect. These details are not reported in the registry record.

Missing data are especially relevant for a monitor-measured endpoint, because measurements may be absent or unusable. The registry record does not report missingness by group, reasons for missing observations, monitor compliance, imputation, or sensitivity analyses. It does not say whether the primary analysis included all randomized participants or a subset with available measurements. The enrollment and adverse-event risk counts cannot substitute for endpoint-specific analysis counts.

The record therefore does not establish the analysis population, missing-data approach, or multiplicity strategy. These omissions limit assessment of how robust any outcome estimate would be, even apart from the absence of a single reported primary comparison.

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 fields list zero participants affected by serious adverse events in the mobile app plus activity monitor group and zero in the activity monitor group. The record lists 15 participants at risk in each group for these fields. It also lists zero affected by other adverse events in each group. These are the registry's reported counts; they do not describe event severity beyond the serious-event classification or provide individual event narratives.

The death fields are null for both groups. A null entry is not the same as a recorded zero, so deaths are not reported in the registry record. The record lists no serious adverse-event terms. It does not provide details about how adverse events were collected, the period of active safety monitoring, definitions used, or whether all events were submitted.

Zero affected in the reported fields should be read as no events recorded in those fields, not as proof that no adverse events occurred under any definition or that an intervention has no safety risks. The risk counts shown for safety reporting also should not be assumed to equal the number with usable primary outcome measurements. These safety entries are descriptive registry information and do not replace a complete safety analysis.

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

The record establishes that the MOTHER study was a completed randomized pilot trial comparing a mobile phone-based physical activity program plus an activity monitor with an activity monitor alone in pregnant women described as physically inactive. Its primary measure was monitor-measured steps, defined as change in weekly mean steps per day at 12 weeks. These design details clarify what the trial sought to evaluate. They do not establish the result of the comparison.

The registry does not report one primary-outcome comparison, and it does not provide the group estimates, effect estimate, uncertainty interval, or test result needed to quantify the difference. As a result, the posted information cannot show whether the activity measure was higher or lower in either group, how large a difference may have been, or how precisely any difference was estimated. It is not appropriate to describe the intervention as effective or ineffective based on the endpoint definition or study status alone.

The study's pilot designation matters for interpretation. Pilot work is commonly used to estimate potential effects and assess the feasibility of further research. In general, an estimate from a pilot may be uncertain, and enrollment alone does not indicate the precision of an effect estimate. Here, the primary comparison itself is not reported, and a sample-size justification is not reported in the registry record. The planning assumptions associated with illustrations are not observed results or evidence of observed power.

The listed secondary outcome, 7-Day Physical Activity Recall, does not supply a reported result in the registry information available for interpretation. The safety fields report zero affected by serious and other adverse events in each group, while deaths are not reported in the registry record. Those entries should be understood as limited registry fields, not as a complete statement about all possible safety outcomes.

In short, the record describes the trial's question and its endpoint, but does not provide the primary result needed to answer that question. The absence of a reported comparison is not evidence that the two groups had the same activity levels, and it is not evidence that the intervention changed activity. It is a limit on what can be concluded from the registry record.

13. Why This Trial Matters Statistically

This trial is statistically interesting because its design and endpoint are clearly identifiable, while the information needed to interpret its main comparison is not reported as one result. The contrast is an add-on comparison: a mobile phone-based physical activity program plus an activity monitor versus an activity monitor alone. That framing matters because it concerns the program's additional contribution over the monitor, rather than a comparison with no monitor.

The outcome is continuous and defined as change in weekly mean steps per day at 12 weeks. This makes the choice of summary and comparison important. A group mean and standard deviation can describe observed values, but the intervention question requires a between-group contrast and an account of its uncertainty. The registry specifies the mean and standard deviation as the summary conventions, yet does not report a single primary contrast or its estimate. Readers cannot infer an effect simply from the outcome definition.

The trial is described as a pilot. Statistically, that designation encourages careful attention to estimation and uncertainty rather than treating a study as a definitive test. But a pilot's purpose does not remove the need to report the estimates that it was intended to inform. In this record, the primary outcome is flagged as having several categories or time points, with no single comparison selected for presentation. This makes the lack of a reported estimate especially consequential: the intended measurement is apparent, but the result cannot be evaluated.

The registry also lists a secondary recall measure and contains safety counts, which illustrate that different kinds of evidence should not be conflated. A secondary outcome is not a substitute for an unreported primary comparison, and zero events recorded in safety fields do not answer the physical activity question. Taken together, the record highlights how transparent specification of outcomes, analysis populations, missing-data handling, and planned comparisons is necessary for readers to distinguish study design from study findings.

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 primary limitation for interpreting this trial is that the registry record does not report a single primary-outcome comparison. Although the endpoint is defined as change in weekly mean steps per day at 12 weeks, the record flags several categories or time points and does not provide one estimate. Without group summaries, a between-group effect, or an uncertainty interval, neither direction nor magnitude nor precision can be assessed.

The registry record also does not report participant flow, baseline outcome values, the number contributing monitor data, or reasons for missing data. The enrollment entry and the safety risk counts do not indicate how many participants had complete primary outcome measurements. Monitor wear requirements, data quality rules, and handling of missing or invalid observations are not described. These omissions limit assessment of how representative any measured activity values would be, even if results were available.

Analysis details are not reported in the registry record. There is no stated model, analysis population, covariate strategy, repeated-measure approach, or method for handling multiple categories or time points. The record lists two outcome measures but does not describe a hierarchy or multiplicity procedure. It also does not report a sample-size justification. The planning assumptions are not a substitute for that justification or for a reported trial result.

The intervention itself is described at a broad level. The specific mobile program content, delivery, uptake, adherence, and activity monitor details are not reported in the registry record. The masking designation is single, but who was masked and how masking was implemented are not described. Finally, adverse-event fields are limited: deaths are not reported, and the record does not describe collection procedures or the safety-monitoring period. These limitations concern what can be established from the registry record and should not be mistaken for proof that the study did not address these matters in other materials.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The MOTHER (Mobile Technologies to Help Enhancing Regular Physical Activity) Trial for Pregnant Women — NCT01461707.
• Registry record last updated 2017-11-30; status last verified 2017-10.
• Results first posted 2017-05-05.
• 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

NCT01461707, titled The MOTHER (Mobile Technologies to Help Enhancing Regular Physical Activity) Trial for Pregnant Women, is recorded as a completed randomized, single-masked, parallel-group pilot study. The registry describes a comparison between a mobile phone-based physical activity program plus an activity monitor and an activity monitor alone. Enrollment is listed as 30; the recorded start is 2012-10 and primary completion is 2014-05.

The primary measure is physical activity monitor-measured steps, described as change in weekly mean steps per day at 12 weeks. The registry flags the primary outcome as having several categories or time points and does not reduce it to one comparison. The 7-Day Physical Activity Recall is listed as a secondary outcome. No single primary result or analysis is available in the registry record for interpretation. Safety fields list zero affected by serious and other adverse events in each group; deaths are not reported.