A Personalized Telehealth Intervention for Health and Weight Loss in Postpartum Women: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Personalized Telehealth Intervention for Health and Weight Loss in Postpartum Women (NCT01751230), a randomized na study. The primary outcome is Body Weight Change.

2. Clinical Question

This question is clinically framed around postpartum weight retention, but the primary endpoint is specifically a change in body weight. It is not a direct measure of other health outcomes, and the registry record does not report a broader primary outcome. The study is described as randomized, which concerns how participants were assigned, but details of the assignment process are not reported. The record also does not report the eligibility rules, recruitment approach, or characteristics of the women who took part. Those details matter when judging which postpartum populations the results may describe.

3. Trial Design

The registry describes a randomized, single-masked, parallel-group study and lists its status as completed. The listed enrollment is 40. The posted outcome summaries report results for 19 participants in WIC E-Moms and 16 in WIC Moms. These are the group counts attached to the primary outcome summaries; the registry record does not explain how they relate to the enrollment figure or whether participants without an outcome were excluded from those summaries.

The two groups received different approaches to postpartum weight management. WIC E-Moms used a personalized diet and exercise plan delivered by smartphone. WIC Moms received nutrition and weight-management advice and services from a WIC clinic. The intervention description notes that a participant could use her own phone or borrow one for the study. The available text describing the intervention is incomplete, so further details of its delivery are not reported in the registry record.

“Single-masked” is the registry’s masking classification, but it does not identify which people were masked. Whether participants, staff, or outcome assessors were masked is not reported in the registry record. The randomization method, allocation concealment, and any stratification are also not reported. The parallel design means the record describes separate groups rather than a crossover comparison; details beyond that classification are not reported.

The study began in 2013-08, and primary completion is listed as 2014-10. It is sponsored by Pennington Biomedical Research Center. The phase is listed as NA. The registry lists four outcome measures, while no secondary results are posted. No analysis records are listed. The trial’s original statistical plan, including its planned sample-size justification and analysis population, is not reported in the registry record.

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

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 Body Weight Change, measured over Baseline and 16 weeks.

The primary endpoint is body-weight change, measured in kilograms, from baseline to the end of the 16-week intervention. Weight is a continuous measure: each participant’s outcome can take a range of values rather than being limited to a category such as improved or not improved. The posted group summaries report mean change, a measure of the average change within each group.

A change score expresses how the measured value differs from baseline at the later assessment. Negative change in the WIC E-Moms summary indicates an average decrease in weight, while positive change in the WIC Moms summary indicates an average increase. These are group means, not descriptions of every participant’s individual outcome. The registry does not provide individual participant results or the distribution of changes within either group.

Using a continuous endpoint preserves information about the size and direction of weight changes. Comparing mean changes between randomized groups can address whether their average changes differed over the study period. The endpoint is relevant to the stated study question about postpartum weight retention, but it does not by itself describe other health outcomes or explain why a change occurred. The primary outcome’s stated timeframe is baseline and 16 weeks; further details about the measurement procedure, timing windows, or handling of measurements not collected at the planned time are not reported in the registry record.

7. Results Posted in the Registry

• WIC Moms: mean 1.80 versus -0.10 on control; difference 1.90 (95% CI -0.59 to 4.39), standardized effect d = 0.50; z-test p = 0.135.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous, and the registry reports each group’s mean change and standard error. A comparison of means is a way to summarize whether the average outcome differed between groups. The reported estimate is the mean difference, given as WIC Moms minus WIC E-Moms. Keeping that subtraction order in mind is essential when interpreting its sign: a positive estimate means the comparator-group mean is higher than the intervention-group mean on the change scale.

What does a mean summarize?

A mean is the arithmetic average of the observed values in a group. It gives one compact description of the group’s center, but it does not show the full distribution. Participants can have different individual changes even when the group mean is close to zero. The registry does not report individual values, medians, ranges, or other distribution summaries for this outcome. As a result, the means alone cannot show whether most participants changed a little, whether changes varied widely, or whether a small number of large changes influenced the average.

What does the standard error describe?

The posted standard errors are 0.9 kg in both groups. In general, a standard error describes the sampling uncertainty of an estimated statistic, such as a group mean. It is not the same as the spread of individual participant outcomes. A standard error is useful for understanding the precision of a mean and contributes to the uncertainty around a comparison. The registry gives the standard error but does not provide the group standard deviations as primary outcome summaries. Further detail about how the standard errors were calculated is not reported in the registry record.

How should the mean difference be read?

The estimated mean difference is 1.9 kg, defined as the WIC Moms mean change minus the WIC E-Moms mean change. It compares group averages on the registered change scale. It does not mean that each participant in one group differed from a particular participant in the other group by that amount. Nor does it describe a change from baseline for an individual. It is an estimate of the between-group contrast in average change.

What does a confidence interval contribute?

In general, a confidence interval expresses uncertainty around an estimate using a range of values compatible with the data and the method’s assumptions. It helps show which effect sizes remain plausible, rather than presenting only a single point estimate. The reported interval for this comparison crosses zero. Since zero represents no difference in mean change under the stated contrast, the interval includes both a no-difference value and values on either side. The width of the interval is a key part of interpreting the result, not merely a visual addition to the point estimate.

What does the p-value contribute?

The unadjusted p-value is 0.135. In general, a p-value measures how unusual data at least as inconsistent with a specified null model would be if that model and the test assumptions held. It does not measure the probability that the null hypothesis is true, and it does not tell whether an effect is important. The registry’s planning assumptions mention a two-sided significance level of 0.05 for the separate sample-size illustration. That planning value should not be mistaken for a complete report of the trial’s prespecified analysis procedure. The registry does not report its original hypothesis-testing plan.

What does randomization contribute?

Random allocation is intended to create groups whose differences, on average, are not systematically determined by the assignment process. It provides a basis for comparing outcomes between groups. The record labels allocation as randomized, but does not report the sequence-generation method, concealment procedures, or checks on implementation. Randomization does not guarantee that observed groups will be identical in a small study, and it does not resolve concerns about missing outcomes or deviations from the assigned interventions. Those details are not reported in the registry record.

What does the posted analysis leave unknown?

The record lists no analysis entries, while the primary outcome summaries and an unadjusted comparison are available. It does not report whether the primary comparison followed an intention-to-treat approach, which participants were included, how missing weights were handled, whether baseline weight was used for adjustment, or whether any model assumptions were checked. It also does not report a protocol-defined analysis plan, interim analyses, or sensitivity analyses. These omissions limit the ability to assess how the displayed estimate was obtained and how robust it is to alternative reasonable analysis choices.

General statistical interpretation should distinguish estimation from testing. The mean difference estimates the size and direction of the contrast; its interval describes precision; and the p-value summarizes compatibility with a null model under specified assumptions. None of these quantities alone establishes causation, clinical importance, or generalizability. In this study, the randomized design is relevant, but interpretation also depends on the completeness of outcome data, fidelity to assignment, and appropriate analysis—information not reported in the registry record.

10. Confidence Intervals and Precision

Precision concerns how narrowly the data locate the estimated mean difference. The posted estimate is 1.9 kg, with a confidence interval that extends from below zero to above zero. Its inclusion of zero means the interval is compatible with no difference as well as with differences in either direction. The interval therefore does not pinpoint the direction of the population mean contrast.

The interval is also broad enough to leave considerable uncertainty about the size of the difference. A point estimate alone can appear more definite than the underlying evidence warrants; the interval makes clear that a range of effects remains compatible with the observed summary data and the interval method. The reported p-value of 0.135 is consistent with this uncertainty, but the interval gives information about plausible effect sizes that the p-value does not convey by itself.

Both groups have a reported standard error of 0.9 kg. Standard errors are measures of uncertainty in estimated means, not measures of the spread of individual weight changes. The group counts attached to the summaries are 19 for WIC E-Moms and 16 for WIC Moms. With these group summaries, the comparison should be read as an estimate with limited precision, not as an exact description of the difference that would occur in a broader population.

More precise confidence limits cannot be stated without exceeding the registry’s displayed rounding constraint. The registry does not report an adjusted interval, a sensitivity analysis, or enough detail to assess whether alternative analysis choices would materially change the precision. The interval also does not account for questions that cannot be evaluated from the record, such as the effect of missing outcome measurements.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed mean difference, not the trial’s original design calculation. They are expressed as participants per arm, not as a combined total and not as total events. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each row uses the stated fraction of the observed effect as the effect to detect. The trial’s own original sample-size assumptions are not reported in the registry record.

The 80% power column gives the illustrated number of participants per arm for a design intended to have 80% power under those assumptions and for the effect size used in that row. The corresponding figures are 63 participants per arm for planning for 100% of the observed effect, 111 for planning for 75% of the observed effect, and 249 for planning for 50% of the observed effect. The 90% power column gives the analogous planning figures for a design intended to have 90% power: 84, 148, and 333 participants per arm, respectively, for those same effect fractions.

Power is the probability that a planned statistical test will detect an effect of the assumed size under the specified model and assumptions. The higher-power column requires more participants per arm in each listed scenario. Smaller effects also require more participants per arm, because a smaller difference is harder to distinguish from sampling variation. The curve presents this planning relationship across effect assumptions; it should be interpreted using the same stated assumptions rather than as another result observed in the trial.

This is not observed power. The planning figures do not describe the probability that the completed study’s result is correct, and they do not change the uncertainty in the posted estimate. They are illustrations derived from the observed effect, so they depend on that estimate and should not be mistaken for the original protocol’s planned target.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 1.900; pooled standard deviation σ = 3.780.
2. n = 2 × (1.96 + 0.842)² × 3.780² / 1.900² = 62.1, rounded up to 63 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 1.9                      # observed difference in means
sigma <- 3.77961036952945                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1751230)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 63 (80% power), 84 (90% power)
 75% of observed effect: n per arm = 111 (80% power), 148 (90% power)
 50% of observed effect: n per arm = 249 (80% power), 333 (90% power)
power.t.test: 63.1 
Simulated power at n = 63 per arm: 0.796 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures, but only the primary outcome is described in the available results, and no secondary results are posted. The record therefore does not allow a full assessment of how the study’s outcomes were analyzed together or whether any outcome-specific findings were selected for reporting. The planned hierarchy among outcomes, if any, is not reported in the registry record.

Multiplicity arises when several hypotheses or outcomes are examined. In general, performing more statistical tests can increase the chance of obtaining a seemingly notable result by chance. Researchers may address this through a prespecified outcome hierarchy, adjustment procedures, or clearly exploratory interpretation. The registry record does not report whether any multiplicity strategy was planned or used. The unadjusted p-value for the primary comparison should therefore be read as an unadjusted result, not as evidence that a particular multiplicity procedure was applied.

Missing-data handling is also not reported. The registry does not state how many participants lacked a 16-week weight measurement, whether missing values were imputed, or whether analyses used only participants with observed outcomes. The group counts associated with the posted means are 19 and 16, while the registry enrollment is listed as 40; the record does not explain the relationship between these counts. It is not possible to infer from the summary alone why the counts differ or how any unavailable measurements were handled.

The analysis population is not reported. The record does not say whether the comparison included all randomized participants, only participants who completed the intervention, or another defined group. It also does not describe adherence, crossovers, exclusions after randomization, or sensitivity analyses. These are important because conclusions from a randomized comparison can depend on who is included and how incomplete outcomes are treated.

The registry lists no analysis records. It does not report a full statistical analysis plan, prespecified covariates, interim analyses, or procedures for dealing with multiple outcomes. Their absence from the registry record should be understood as missing reporting, not evidence that a particular method was or was not used.

14. 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.

Most frequent non-serious adverse event terms

The serious adverse event figures report zero affected participants in WIC E-Moms among 19 at risk and zero in WIC Moms among 16 at risk. These are counts, not estimates of comparative safety. Zero reported serious events in the recorded groups does not establish that serious events cannot occur, nor does it establish equal risk between groups.

For other adverse events, the record reports 4 affected participants among 19 at risk in WIC E-Moms and 1 among 16 at risk in WIC Moms. The registry does not provide event terms for serious adverse events, and no serious terms are listed. The group-level figures do not describe event severity or timing for the other adverse events, and the record does not clarify whether participants could have experienced more than one event.

Deaths are not reported in the registry record. The duration and completeness of safety follow-up, definitions used for adverse-event categories, and methods for collecting events are not reported. These safety figures should therefore be read as the counts posted for the study, with limited detail for assessing the nature or timing of events.

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

The posted results describe average weight change during a 16-week intervention period. WIC E-Moms had a reported mean change of -0.1 kg, and WIC Moms had a reported mean change of 1.8 kg. The unadjusted mean difference, expressed as WIC Moms minus WIC E-Moms, is 1.9 kg. This is the result for the registry’s primary endpoint and the comparison represented by the posted summaries.

The estimate points toward a higher average change in the WIC Moms group, but the uncertainty is substantial: the confidence interval crosses zero and the unadjusted p-value is 0.135. The data therefore do not precisely establish the direction or size of the difference in mean change. The mean summaries also cannot show how individual participants changed, how varied their outcomes were, or whether the average reflects a pattern shared across participants.

The result does not establish that the smartphone intervention caused weight loss or weight gain. Although the study is classified as randomized, the registry record does not report enough detail about allocation procedures, missing weights, the analysis population, or the statistical plan to evaluate the complete analysis process. The record also does not report longer-term follow-up, so the posted endpoint cannot establish whether changes persisted beyond the stated timeframe.

Nor does this endpoint answer broader questions about health, well-being, or other postpartum outcomes. Four outcome measures are listed, but secondary results are not posted. The observed adverse-event counts are limited summaries and do not establish comparative safety. The findings should be understood as an imprecise result from the recorded groups and period, rather than a definitive conclusion about the intervention’s effects or about postpartum weight management generally.

Clinical importance cannot be determined from the mean difference alone. The registry does not report a threshold for a meaningful weight change or patient-centered interpretation of the observed changes. A statistically estimated difference and a clinically meaningful difference are related but distinct concepts. The available record supports describing the estimate and its uncertainty, not asserting whether the magnitude matters to participants.

16. Why This Trial Matters Statistically

This trial illustrates why a point estimate should be interpreted together with its uncertainty. The mean difference of 1.9 kg gives a concise summary of the contrast, but the confidence interval crosses zero and the unadjusted p-value is 0.135. Considering these measures together avoids treating the point estimate as a precise or conclusive finding.

It also demonstrates the distinction between a group average and individual outcomes. Mean change is an interpretable endpoint for a weight-management question, but a group mean does not reveal how consistently participants changed or how much their experiences varied. The standard error concerns uncertainty in the mean; it is not the standard deviation of participant changes. Keeping these quantities distinct is important when reading clinical trial summaries.

The registry’s sample-size illustrations show how planning depends on the assumed effect size and desired power. The listed figures rise as the assumed effect becomes a smaller fraction of the observed effect, illustrating the general statistical challenge of detecting smaller differences. These illustrations are separate from the completed trial’s result and do not describe its original design assumptions.

The record also highlights the importance of complete reporting. Details of missing outcomes, analysis populations, multiplicity, and the original statistical plan are not reported. Without these, readers cannot fully judge how the comparison was produced or how robust it is. The randomized classification is relevant, but it cannot substitute for reporting the methods and the handling of incomplete data.

Finally, the example shows why a nonsignificant-looking result should not be translated into proof of no difference, just as a directional point estimate should not be treated as proof of benefit or harm. Statistical interpretation is strongest when it separates the observed estimate, its precision, the assumptions behind the analysis, and the limits of the registry record.

17. 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 posted primary comparison is based on a limited number of outcome observations, with group summaries for 19 participants in WIC E-Moms and 16 in WIC Moms. The registry lists enrollment as 40 but does not explain the relation between that value and the group counts in the outcome summaries. It is not possible to determine from the record whether the difference reflects missing measurements, eligibility or analysis decisions, or another reason.

The intervention description available in the registry is incomplete. It identifies a personalized diet and exercise plan delivered by smartphone, but does not report the full intervention content, contact schedule, level of engagement, or adherence. The comparator is described as advice and services from a WIC clinic, without further details of what participants received. The record does not report whether intervention exposure or comparator services varied between participants.

The record classifies the study as single-masked but does not say who was masked. Details of randomization and allocation concealment are also not reported. These omissions limit assessment of possible bias in assignment, delivery, or outcome measurement. The registry does not describe the weight measurement procedure or whether assessors were masked.

Statistical reporting is limited. No analysis records are listed, and the original analysis plan, analysis population, missing-data methods, covariate adjustment, multiplicity procedures, and sensitivity analyses are not reported. Secondary results are not posted despite four outcome measures being listed. The confidence interval crosses zero, indicating uncertainty about the direction of the mean difference, and the registry does not provide participant-level outcomes or full distribution summaries.

The results concern weight change from baseline to 16 weeks. Longer-term outcomes, participant characteristics, and broader measures of health are not reported in the posted results. The registry record alone therefore supports only a bounded interpretation of the reported endpoint and does not establish how well the findings apply to other postpartum populations or settings.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: A Personalized Telehealth Intervention for Health and Weight Loss in Postpartum Women — NCT01751230.
• Registry record last updated 2021-08-24; status last verified 2021-08.
• Results first posted 2019-03-26.
• 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.

21. Record Summary

NCT01751230 is a completed randomized, single-masked, parallel-group study of a personalized telehealth intervention for postpartum women. The sponsor is Pennington Biomedical Research Center. The registry lists enrollment as 40, with study start in 2013-08 and primary completion in 2014-10. The phase is listed as NA.

The primary endpoint is body-weight change from baseline to 16 weeks. The WIC E-Moms mean change was -0.1 kg, and the WIC Moms mean change was 1.8 kg. The unadjusted mean difference, WIC Moms minus WIC E-Moms, was 1.9 kg, with an unadjusted p-value of 0.135. The confidence interval crosses zero, so the direction and size of the difference remain uncertain.

The registry lists four outcome measures, but no secondary results or analysis records. Details of the original statistical plan, missing-data handling, analysis populations, and several design procedures are not reported in the registry record. The posted summaries should be interpreted as limited evidence about the primary outcome over the stated study period.