Postpartum Pelvic Floor Muscle Training in Women With and Without Injured Pelvic Floor Muscles: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Postpartum Pelvic Floor Muscle Training in Women With and Without Injured Pelvic Floor Muscles (NCT01069484), a randomized na study. The primary outcome is Urinary Incontinence (Prevalence).

2. Clinical Question

The clinical question concerns a structured, supervised training program added to customary information and instruction. It does not compare training with an absence of all pelvic floor guidance: both groups received a leaflet and initial instruction, and control participants could train independently. The stated study aim also distinguishes women with and without pelvic floor muscle injury. How those groups were defined for analysis, and whether the primary question was evaluated separately by injury status, is not reported in the registry record.

3. Trial Design

The registry describes a randomized, single-blind, parallel-group trial. The listed enrollment is 175 participants. The record identifies two arms: postpartum pelvic floor muscle training and control. It does not report how the random sequence was generated, how assignments were concealed, or who was blinded. The meaning of single blinding in practice is therefore not clear from the registry record.

Both groups received the customary postnatal leaflet and thorough initial instruction on how to contract the pelvic floor muscles correctly. The training arm additionally received weekly supervised group training led by physiotherapists and was asked to train at home every day. The control arm received no further intervention, although participants were not discouraged from training on their own. This means the assigned treatment contrast is between a structured training program and customary information and instruction, not between training and no pelvic floor guidance whatsoever.

The intended population was primiparous women who delivered a singleton baby vaginally after more than 32 weeks of gestation and met the other eligibility criteria in the clinical question. The registry names pelvic floor muscle injury as a feature relevant to the study aim, but does not describe the injury assessment or its classification. The record lists urinary incontinence prevalence as the primary outcome at 6 months postpartum, at the end of the intervention, and positive pad test urinary incontinence as a secondary outcome.

The trial status is completed. The registry lists the study start as 2010-02 and primary completion as 2012-12. More detailed information about follow-up procedures, adherence, protocol deviations, or the timing of assessments beyond the stated endpoint timeframe 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Primiparous women who delivered a singleton baby vaginally after more than 32 weeks of gestation. They had to have Scandinavian language skills, no severe perineal tearing, no prior abortion or stillbirth after 16 weeks of gestation, and no illnesses interfering with the ability to follow-up.

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: Assuming a similar difference among comparison groups as found by Mørkved and Bø (1997), a two-sided significance of \< 0.05 and a power of 0.90 requiered a total of 62 women. For applying stratified analysis on major levator ani (LA) muscle defects, the statistical advice was to aim for 80 women with- and 80 women without major LA muscle defects.

6. Primary Endpoint

The registry lists the primary outcome as Urinary Incontinence (Prevalence), measured over 6 months postpartum (end of intervention).

The primary endpoint is urinary incontinence prevalence at 6 months postpartum, described as the end of the intervention. Urinary incontinence was assessed using the International Consultation on Incontinence Questionnaire Urinary Incontinence Short Form. A woman was classified as incontinent if she reported leaking urine, answering yes or no, at any frequency. Thus, the endpoint is a binary classification of whether leakage was reported, rather than a measure of leakage frequency or severity.

A binary prevalence endpoint can be used to compare the proportion of participants meeting a stated condition between trial groups. Its interpretation depends on the question wording and the assessment method: in this trial, any reported leakage counted, regardless of frequency. The endpoint therefore captures a broad occurrence measure and does not, by itself, describe the amount of leakage, its effect on daily life, or changes in symptoms over time.

The registry does not report the number of participants classified as incontinent in either arm, the number assessed, or a numerical comparison. It also does not report a single primary-outcome comparison in the posted results. As a result, the direction, size, and precision of any between-group difference in this endpoint cannot be described from the registry record. The named secondary outcome is urinary incontinence assessed by a positive pad test; its results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

For a binary endpoint such as urinary incontinence classified yes or no, a statistical comparison usually starts with the number of participants meeting the endpoint and the number assessed in each group. Those counts can be expressed as group-specific proportions, followed by a contrast between groups. General statistical interpretation then asks whether the contrast is compatible with no difference and how uncertain the estimate is. The registry record does not report the counts, denominators, estimate, confidence interval, or test for the primary endpoint, so no trial-specific calculation or inferential result can be described.

What does a confidence interval communicate?

In general, a confidence interval describes the range of effect estimates that are reasonably compatible with the data and the method used to calculate the interval. A narrow interval indicates greater statistical precision than a wide interval, while an interval spanning values on both sides of no difference can leave direction uncertain. The registry does not report a confidence interval for the primary outcome. It is therefore not possible to characterize the precision of the trial’s primary comparison from this record.

What does a significance test communicate?

In general, a significance test evaluates how unusual the observed data would be under a specified null hypothesis and assumptions. A p-value is not the probability that the null hypothesis is true, and it does not measure clinical importance. The registry record does not report a primary-outcome p-value or identify the test used. No conclusion about statistical significance can be drawn from the endpoint description or trial design alone.

Why does the endpoint definition matter?

The trial counted any self-reported urine leakage at any frequency as urinary incontinence. This creates a binary outcome: a participant either meets the stated definition or does not. Such an outcome can make a group comparison relatively direct, but it compresses different experiences into the same category. It does not distinguish occasional leakage from more frequent leakage, and it does not capture severity unless the analysis separately uses such information. No such additional primary-outcome analysis is reported in the registry record.

The measure was the International Consultation on Incontinence Questionnaire Urinary Incontinence Short Form. The registry describes the classification rule but does not report questionnaire scores, the analysis method, or whether any change from an earlier assessment was evaluated. The stated primary endpoint is prevalence at 6 months postpartum, not a reported change score.

What can randomization establish?

In general, random allocation is intended to make assignment independent of participant characteristics, so that a well-conducted comparison can estimate the effect of assignment to the intervention rather than simply differences between self-selected groups. Randomization does not guarantee that groups are identical in every characteristic, and it cannot resolve problems such as missing outcome data or departures from assigned treatment. The record identifies randomized allocation but does not report sequence generation, concealment, baseline balance, adherence, or the analysis population. The strength of the actual comparison therefore cannot be fully assessed from the registry entry.

The registry labels the trial single blind but does not state who was blinded. In general, masking can reduce the influence of knowledge of assignment on participant reports, care, or outcome assessment, depending on who is masked and how the outcome is measured. Because the endpoint is based on participant report and the record does not identify who was masked, the practical role of masking cannot be determined from the information recorded.

What do the planning assumptions mean?

The record describes a separate planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect. Such an illustration describes hypothetical sample-size requirements under specified assumptions; it is not the number of participants actually observed in the trial and is not observed power. The registry entry does not give the calculated planning values or a trial-specific sample-size justification. The illustration should not be interpreted as evidence that the original trial was designed around those assumptions.

There are no reported recalculated estimates or a stated discrepancy between a sponsor analysis and a recalculation in the registry information. Accordingly, there is no alternative numerical estimate to compare with a sponsor analysis. More broadly, the lack of a reported primary contrast prevents assessment of effect size, statistical uncertainty, and whether a particular statistical model or test was appropriate for the observed data.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and two analyses. The primary outcome is urinary incontinence prevalence, and the secondary outcome is urinary incontinence assessed by a positive pad test. The record does not report the results for either outcome as a single comparison. It also does not describe a plan for controlling the chance of false-positive findings when evaluating more than one outcome or analysis. Whether any multiplicity adjustment was planned or used is not reported in the registry record.

Missing-data handling is not described. In particular, the record does not state how many participants completed the 6-month questionnaire, how many had a classifiable outcome, or what method was used for participants without outcome data. The endpoint denominators may differ from the enrollment or safety denominators, but the primary-outcome denominators are not reported. No assumptions about missing outcomes, imputation, or sensitivity analyses can be inferred.

The record also does not identify the primary analysis population, such as whether all randomized participants were included according to assigned group or whether another population was used. Analysis by injury status, per-protocol analysis, and other subgroup or sensitivity analyses are not described. These gaps matter because analysis choices and missingness can affect both the estimate and its uncertainty. They prevent a full assessment of how the primary outcome was analyzed and how robust any result would be to alternative assumptions.

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.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: any serious adverse effect from pelvic floor muscle training (0.0%).

The registry reports zero serious adverse effects attributed to pelvic floor muscle training among 87 participants at risk in the training arm. It also reports zero in the control arm among 88 participants at risk. The listed serious adverse-effect term is “Any serious adverse effect from pelvic floor muscle training,” reported as 0.0%.

These figures describe the serious adverse effects recorded in the registry for the groups and participants at risk. They should not be read as proof that no adverse effects of any kind occurred. The record does not provide a broader account of non-serious adverse events, the method or duration of safety monitoring, or details about how events were collected. Death counts are not reported in the registry record.

The safety figures are distinct from the primary efficacy endpoint. They do not supply information about urinary incontinence prevalence, and they do not establish the quality or completeness of outcome follow-up. The registry’s zero serious adverse-effect counts are a description of the recorded safety data, not a basis for conclusions beyond those data.

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

The registry record establishes that the trial was designed to compare a structured postpartum pelvic floor muscle training program with a control condition in primiparous women who met specified eligibility criteria. Both groups received a leaflet and initial instruction; the training group additionally received weekly supervised group training and daily home training. The primary outcome was urinary incontinence prevalence at 6 months postpartum, based on self-reported leakage at any frequency.

What the record does not establish is the primary outcome result. It does not report how many participants in either group met the endpoint, a between-group estimate, a confidence interval, or a significance test. Without those items, the direction and size of the outcome contrast, and the precision with which it was estimated, cannot be described. The absence of a reported comparison is not evidence that the groups had the same outcome.

The record does not establish whether the results differed according to pelvic floor muscle injury status, despite the study aim referring to women with and without injury. It also does not report adherence, primary-outcome follow-up counts, or a missing-data approach. Therefore, it cannot show how the assigned training program was followed or how complete the primary endpoint data were.

Likewise, the reported absence of serious adverse effects is limited to the safety information recorded for the two arms. It should not be extended to all possible harms or interpreted as a complete account of adverse events. Taken together, the registry provides useful information about the question, intervention, comparator, and endpoint definition, but insufficient outcome reporting to judge the observed primary result or its uncertainty.

13. Why This Trial Matters Statistically

This trial is statistically notable for the distinction between a clearly described research question and an interpretable treatment-effect estimate. The registry identifies randomized allocation, a parallel-group comparison, an eligibility population, an intervention contrast, and a binary primary endpoint. Those elements help define what the study set out to examine. They do not substitute for the group outcome counts and comparison needed to evaluate what the trial found.

The endpoint definition also illustrates how measurement choices shape an analysis. Counting any self-reported leakage at any frequency creates a binary prevalence outcome. That can answer whether leakage was reported under the specified definition, but it does not describe frequency, severity, or burden. A statistical result would need to be interpreted in light of this specific classification rather than as a complete description of urinary symptoms.

The intervention contrast is also important. The control group received customary information and initial instruction and was not discouraged from training independently. The comparison therefore concerns the addition of supervised weekly sessions and daily home training to that background, rather than training versus no instruction. This clarification is essential when translating a statistical contrast into a description of the question actually addressed.

Finally, the registry’s sparse outcome reporting illustrates why estimates and measures of uncertainty are central to statistical interpretation. Randomization and a completed-trial status do not reveal the size or precision of an effect. Without an outcome comparison, statistical significance, clinical importance, subgroup patterns, and robustness cannot be evaluated. The record is informative about design and measurement, but the missing primary result sharply limits what can be concluded from it.

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 from the registry is that the primary endpoint is not reported as a single comparison. No group counts, endpoint denominators, effect estimate, confidence interval, or p-value are available in the registry record. The named positive pad test secondary outcome also lacks a reported result. As a consequence, the primary research question cannot be answered from the recorded results.

The registry does not describe how pelvic floor muscle injury was assessed or classified, although the study aim refers to women with and without injury. It does not report whether analyses were stratified by injury status or whether an interaction between injury status and assigned group was evaluated. The record therefore does not support assessment of differences in outcomes across those groups.

Several trial-conduct details are not reported in the registry record: sequence generation, allocation concealment, the identity of those masked, adherence to training, primary-outcome follow-up numbers, missing-data handling, and the primary analysis population. These omissions limit evaluation of the risk of bias and the completeness of the endpoint data, without establishing that any particular bias or data problem occurred.

The registry describes a planning illustration but does not provide its calculated values or a trial-specific sample-size justification. It is therefore not possible to assess the precision the trial was intended to achieve from that information. The safety report is limited to the listed serious adverse-effect counts; broader safety monitoring and non-serious events are not detailed. These limitations concern the information available in the registry record and do not establish what may have been reported elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Postpartum Pelvic Floor Muscle Training in Women With and Without Injured Pelvic Floor Muscles — NCT01069484.
• Registry record last updated 2016-12-01; status last verified 2016-10.
• Results first posted 2016-12-01.
• 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 identifies a completed, randomized, single-blind, parallel-group trial with an enrollment of 175. The study compared postpartum pelvic floor muscle training with control among primiparous women who met the stated delivery and eligibility criteria. The training group received weekly supervised group sessions and daily home training in addition to the leaflet and initial instruction received by both groups.

The primary outcome was urinary incontinence prevalence at 6 months postpartum, defined by self-reported urine leakage at any frequency using the International Consultation on Incontinence Questionnaire Urinary Incontinence Short Form. A positive pad test was listed as a secondary outcome. The registry does not report a single primary-outcome comparison or the secondary outcome results. It records zero serious adverse effects in both groups, with 87 participants at risk in the training arm and 88 in control. Key details about analysis, masking, follow-up, and missing data are not reported in the registry record.