This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Foley Bulb With Low Dose Pitocin Versus Foley Bulb With a Standard Incremental Infusion Protocol for the Induction of Labor (NCT02150954), a randomized phase 4 study. The primary outcome is Time to the Second Stage of Labor.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02150954 |
| Phase | Phase 4 |
| Condition | Induction of Labor |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 121 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Duke University |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes people undergoing induction of labor and explains that Foley bulb induction is used when the cervix is not significantly dilated or effaced. The primary endpoint was recorded during the admission for delivery. The reported primary endpoint groups include 57 participants and 59 participants; the registry enrollment is 121.
Intervention
The arm label describes Foley bulb induction with low dose Pitocin. However, its arm description specifies an infusion starting at 1 milliunit/minute and increasing 2 milliunits per minute every 30 minutes. The difference between the label and the dosing description matters when interpreting which protocol the results represent.
Comparator
The comparator arm is labeled Foley bulb with a standard incremental Pitocin infusion protocol. Its description instead specifies a fixed low dose infusion of 2 mius/min. The registry wording therefore does not make the protocol labels and dosing descriptions consistent, and the record does not resolve that inconsistency.
Primary question
The primary question is how the groups compared on time from Foley bulb placement to the second stage of labor, reported in hours. The registry reports means and inter-quartile ranges for each group, but a two-arm inferential comparison for this endpoint is not reported in the registry record. The posted primary results therefore describe each group rather than establishing a statistically estimated difference between them.
3. Trial Design
The study is listed as a completed, randomized, parallel-group phase 4 trial sponsored by Duke University. The registry gives enrollment as 121. The listed start was 2007-12, and primary completion was 2009-03. Masking is listed as none. The record does not report how the random sequence was generated, whether allocation was concealed, or how participants were assigned to the two arms.
Both groups were described as receiving a Foley bulb and Pitocin, but the protocol descriptions do not align with the arm labels. The low dose arm description specifies an escalating infusion that starts at 1 milliunit/minute and increases 2 milliunits per minute every 30 minutes. The standard incremental arm description specifies a fixed 2 mius/min infusion. This wording appears to reverse the labels’ apparent descriptions of the dosing approaches. The registry record does not clarify which description should govern interpretation, so the exact intended contrast cannot be established from these entries alone.
The primary endpoint was time to the second stage of labor, with a timeframe beginning at Foley bulb placement and extending until the second stage during the delivery admission, up to approximately 4 days. The primary results list 57 participants in one arm and 59 in the other. The registry enrollment is 121, but the record does not explain the difference between enrollment and the endpoint group counts. It also does not state whether the reported endpoint population followed an intention-to-treat, per-protocol, or other analysis approach.
Secondary outcomes listed include cesarean delivery, time to active labor, time to Foley expulsion or removal, uterine hyperstimulation, and neonatal outcomes. Numeric secondary results are posted for cesarean delivery, uterine hyperstimulation, and birthweight. Results for the other listed secondary outcomes are 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.
Before assignment: 121 subjects enrolled. Of the 121 subjects 2 were screen failures and 2 subject were excluded after consent due to meeting exclusion criteria.
Overall Study
| Stage | Foley Bulb Induction With Low Dose Pitocin | Foley Bulb With Standard Incremental Pitocin Infusion Protocol |
|---|---|---|
| STARTED | 58 | 59 |
| COMPLETED | 57 | 59 |
| NOT COMPLETED | 1 | 0 |
Reasons for not completing this period:
| Reason | Foley Bulb Induction With Low Dose Pitocin | Foley Bulb With Standard Incremental Pitocin Infusion Protocol |
|---|---|---|
| Protocol Violation | 1 | 0 |
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.
| Characteristic | Unit | Foley Bulb Induction With Low Dose Pitocin | Foley Bulb With Standard Incremental Pitocin Infusion Protocol | Total |
|---|---|---|---|---|
| Participants analysed | 57 | 59 | 116 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 57 | 59 | 116 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 57 | 59 | 116 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 1 | 1 |
| Race (NIH/OMB): Asian | Participants | 2 | 0 | 2 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 29 | 32 | 61 |
| Race (NIH/OMB): White | Participants | 13 | 14 | 27 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 13 | 12 | 25 |
| Region of Enrollment: United States | participants | 57 | 59 | 116 |
6. Primary Endpoint
The registry lists the primary outcome as Time to the Second Stage of Labor, measured over foley bulb placement until second stage of labor (during admission for delivery, up to approximately 4 days).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Inter-Quartile Range |
| Unit | hours |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is time to the second stage of labor, measured in hours. Its stated timeframe begins with Foley bulb placement and continues until the second stage during the delivery admission, which could last up to approximately 4 days. The endpoint description defines the second stage as the time from complete cervical dilation to delivery of the fetus. In context, the measure appears intended to capture elapsed time from Foley bulb placement until the second stage begins, but the wording combines a time-to-second-stage title with a definition describing the duration from complete dilation to delivery. This leaves some ambiguity about the precise event represented by the reported measure.
Elapsed time is useful for describing the course of labor induction because it retains information about how long the process takes, rather than reducing the outcome to whether a single event occurred. A group mean describes the average reported time, while an inter-quartile range describes the span from the lower to upper quartile and gives a sense of the distribution’s spread. In general, the mean can be influenced by unusually short or long observations, while the inter-quartile range focuses on the middle portion of the observed values.
The registry reports a mean of 18.2 hours, with an inter-quartile range of 13.6 to 27.8, for the arm labeled low dose Pitocin. For the standard incremental arm, it reports a mean of 14.6 hours and an inter-quartile range of 9.9 to 28.3. These are descriptive group summaries. A confidence interval or p-value for the primary between-group contrast is not reported in the registry record, so the precision of a difference between the groups cannot be assessed from a posted primary comparison.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary results describe the time-to-second-stage distributions in the two randomized groups. The registry reports a mean of 18.2 hours for the arm labeled Foley bulb induction with low dose Pitocin and 14.6 hours for the arm labeled Foley bulb with the standard incremental protocol. Their reported inter-quartile ranges are 13.6 to 27.8 hours and 9.9 to 28.3 hours, respectively. These summaries do not by themselves show whether the groups differ beyond the variation in individual labor times.
No primary comparison estimate, confidence interval, or p-value is reported in the registry record. Accordingly, the record does not provide a direct inferential estimate of the primary between-group difference. The inter-quartile ranges are descriptive distribution summaries, not confidence intervals for the difference in means. They should not be used as if they quantify the uncertainty around a treatment contrast.
The secondary results include unadjusted recalculations from posted group counts or means. For cesarean delivery, the recalculated risk difference is 0.047, with an interval extending from -0.128 to 0.222 and an unadjusted p-value of 0.599. For uterine hyperstimulation, the recalculated risk difference is -0.064, with an interval extending from -0.195 to 0.067 and an unadjusted p-value of 0.344. For birthweight, the recalculated mean difference is -115.0 grams, with an interval from -304.6 to 74.56 and an unadjusted p-value of 0.234. Each interval includes zero, so these recalculations do not precisely distinguish a difference from no difference on the corresponding scale.
These secondary comparisons are simple, unadjusted recalculations, not analyses reported by the registry. They do not account for any trial analysis plan or possible adjustment factors, none of which are reported in the registry record. The results also do not resolve the inconsistent arm labels and dosing descriptions. Interpretation should therefore remain tied to the posted group summaries and the uncertainty around the recalculated secondary contrasts, without treating them as definitive evidence of a protocol effect.
The registry lists 121 participants enrolled, while primary endpoint results are reported for groups of 57 and 59. The reason for this difference is not reported in the registry record. The record also does not describe how missing endpoint data, withdrawals, or exclusions were handled. Those omissions limit assessment of how closely the reported analysis groups represent all enrolled participants.
9. Statistical Methods Explained
The posted results include descriptive summaries for the primary endpoint and several secondary outcomes, alongside unadjusted recalculations for selected secondary comparisons. In general, descriptive statistics summarize the observed data, while inferential statistics estimate how compatible a contrast is with a range of possible values. These are different tasks: a group mean is not itself a test of the difference between groups.
What does the primary summary tell us?
The primary endpoint is reported as a mean in hours with an inter-quartile range. In general, a mean is the arithmetic average of observed values. An inter-quartile range gives the interval between the lower and upper quartiles, describing the spread of the middle half of observations. It does not provide the same information as a standard deviation, and neither measure alone gives the uncertainty around a between-group contrast.
The registry reports the primary endpoint mean and inter-quartile range separately for each arm, but does not report a primary comparison estimate. Without a stated contrast and its uncertainty, readers cannot tell how precisely the trial estimates a difference in average time. A comparison could in principle be analyzed with methods appropriate to the outcome distribution, but the statistical method used for the primary endpoint is not reported in the registry record. It would be inappropriate to infer that method from the summaries alone.
How should a confidence interval be read?
In general, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the method used to construct it. For a difference, an interval containing zero is compatible with a range of values that includes no difference, as well as values in either direction. It does not establish that the true difference is exactly zero. An interval extending on both sides of zero also indicates that the point estimate should not be interpreted without considering its uncertainty.
The intervals attached to the secondary recalculations are not registry-reported analyses. They are simple unadjusted calculations based on posted summary statistics. The record lists no reported analyses, so there is no registry analysis output against which to compare these calculations. Their interpretation is descriptive and exploratory, not a substitute for a prespecified analysis.
What do the binary-outcome calculations represent?
For cesarean delivery and uterine hyperstimulation, the recalculated comparison uses a risk difference: the event proportion in one arm minus the event proportion in the comparator arm. In general, a risk difference is expressed on an absolute scale and can be positive or negative depending on the direction of the contrast. Here the recalculated estimates are 0.047 for cesarean delivery and -0.064 for uterine hyperstimulation. Their uncertainty intervals each include zero.
The posted counts are 22 and 20 for cesarean delivery, and 7 and 11 for uterine hyperstimulation, in the arms with 57 and 59 participants, respectively. The record also includes recalculated relative risks and odds ratios, but those are not necessary to understand the main point: the unadjusted intervals do not tightly determine the direction or size of a difference. The p-values are unadjusted and should not be treated as adjusted for the consideration of multiple outcomes.
What do the continuous-outcome calculations represent?
For birthweight, the recalculated comparison is a difference between group means. The posted means are 3065.0 grams and 3180.0 grams, with standard deviations of 530.0 and 511.0 grams. The recalculated mean difference is -115.0 grams, with an interval from -304.6 to 74.56 and an unadjusted p-value of 0.234. In general, the standard deviation describes variation among individual observations, whereas the confidence interval concerns uncertainty in an estimated contrast.
The recalculations use unadjusted summaries and do not account for covariates or other design features. Whether an adjusted method was planned or used is not reported in the registry record. The calculations should not be mistaken for sponsor-reported trial analyses.
Why is over-dispersion relevant in general?
For count or binary data, statistical methods often rely on assumptions about how much variation is expected. In general, over-dispersion occurs when observed variability is greater than a model assumes. If it is ignored, uncertainty can be understated and statistical evidence can appear stronger than warranted. The registry record does not report a model for these outcomes or an assessment of over-dispersion; this is general context, not a claim about the trial’s analysis.
How should the planning illustrations be read?
The planning illustrations are based on observed effects and specified assumptions: a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. They show participant requirements per arm for 80% or 90% power when planning around stated fractions of the observed effect. In general, such figures are conditional illustrations, not observed power and not evidence that the trial was designed with those assumptions. The trial’s own sample-size justification and design assumptions are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary endpoint and multiple secondary outcomes, but it does not report a statistical analysis plan describing how those outcomes were prioritized or analyzed. It lists 9 outcome measures and 7 secondary outcomes, while the reported analyses count is 0. Numeric secondary results are available for only some of the listed outcomes. Whether the remaining outcomes were assessed but omitted, not collected, or not estimable is not reported in the registry record.
No method for controlling multiplicity is reported. In general, when investigators conduct multiple statistical tests, the chance of at least one apparently notable result arising by chance can increase. Methods such as adjustment procedures or a prespecified hierarchy can address that issue, but the registry does not state whether any such approach was planned or used. The unadjusted recalculated p-values should therefore be read as individual exploratory quantities, not as results that account for all outcomes assessed.
Missing-data handling is also not reported in the registry record. The registry enrollment is 121, while the primary outcome groups contain 57 and 59 participants. The record does not explain this difference, identify exclusions or withdrawals, or say how missing primary or secondary measurements were handled. It does not report whether analyses followed intention-to-treat, per-protocol, or another population definition.
These omissions limit evaluation of potential bias. In general, results can be affected if outcome availability is related to participant characteristics or outcomes, but the registry does not provide enough information to assess whether that occurred. The record also does not report interim analyses, stopping rules, covariate adjustment, or sensitivity analyses. Their presence or absence cannot be inferred from the posted results. Consequently, the available evidence supports a description of the reported groups and selected unadjusted comparisons, but not a reconstruction of the full analysis strategy.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Foley Bulb Induction With Low Dose Pitocin | 0 | 57 | 0.0% |
| Foley Bulb With Standard Incremental Pitocin Infusion Protocol | 0 | 59 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Foley Bulb Induction With Low Dose Pitocin | 0 of 57 |
| Foley Bulb With Standard Incremental Pitocin Infusion Protocol | 0 of 59 |
The adverse-event figures list 0 serious adverse events and 0 other adverse events among 57 participants in the arm labeled Foley bulb induction with low dose Pitocin. The corresponding figures are also 0 serious adverse events and 0 other adverse events among 59 participants in the comparator arm. The death fields are null, so deaths are not reported in the registry record; a null entry should not be read as a reported zero.
These figures describe what is recorded in the adverse-event summary. They do not establish that no adverse events of any kind occurred, because the record does not explain event definitions, ascertainment, reporting thresholds, or completeness. The registry lists uterine hyperstimulation as a secondary outcome, with counts reported separately from the adverse-event summary. That endpoint should not be conflated with the serious and other adverse-event fields.
In general, zero events in a registry summary do not demonstrate that an event is impossible or that two approaches have equivalent safety. The group sizes and reporting details matter, and the registry does not provide a separate comparative safety analysis. These entries are therefore a limited description of recorded adverse-event counts, not a comprehensive safety conclusion.
12. What the Result Does, and Does Not, Mean
The posted results establish that the registry records descriptive primary endpoint summaries for the two randomized groups and numeric secondary results for selected outcomes. The primary means were 18.2 hours and 14.6 hours, with overlapping inter-quartile ranges. Without a posted primary contrast and its uncertainty, the record does not show how precisely the trial estimates a difference in time to the second stage.
The unadjusted secondary recalculations also have uncertainty intervals that include zero. They do not sharply distinguish a difference in either direction from no difference on the relevant scale. This is not proof that the groups were identical. Rather, the available estimates are not precise enough to rule out a range of potentially different values, and the registry does not provide a reported analysis to clarify the intended inference.
These results do not establish that either approach is superior, equivalent, or ineffective. They do not answer questions about outcomes for which numeric results are absent, such as time to active labor, time to Foley expulsion or removal, placental abruption, and late fetal heart rate decelerations. They also do not establish comparative safety from the adverse-event summary alone.
Interpretation is further limited by the mismatch between the arm labels and dosing descriptions. The registry record does not resolve which dosing description corresponds to each arm in practice. The exact comparison is therefore less clear than the group labels suggest. The record also does not describe missing-data handling, analysis populations, or the trial’s statistical plan. These gaps prevent a full assessment of bias, precision, and whether the posted results reflect the planned analysis.
In general, a randomized design can support comparisons between assigned groups when allocation, follow-up, and analysis are adequately documented. Randomization alone does not resolve ambiguities in outcome definitions or incomplete reporting. The registry should be read as a record of the stated design and posted results, not as a complete account of every methodological decision or clinical consequence.
13. Why This Trial Matters Statistically
This trial is statistically informative because it illustrates the difference between reporting group summaries and reporting a treatment contrast. The primary outcome has a mean and inter-quartile range for each arm, but no posted estimate of the between-group difference, confidence interval, or p-value. Readers can describe the observed distributions, but cannot assess the precision of the primary contrast from the registry record.
The secondary outcomes illustrate a related issue. Recalculated unadjusted comparisons can be made from the posted counts and means, but those calculations are not registry-reported analyses. Their intervals include zero, and no analysis plan or multiplicity approach is described. This is a reminder that exploratory recalculations may aid interpretation while remaining distinct from a prespecified trial analysis.
The arm-description inconsistency is also important. A trial’s group labels and protocol details need to identify the actual contrast clearly. Here the arm names and infusion descriptions do not align, and the record does not resolve the discrepancy. That limits the ability to connect a statistical contrast to a specific dosing approach.
Finally, the distinction between enrollment and outcome-group counts, together with the absence of missing-data and analysis-population details, limits assessment of who contributed to each estimate. These are not merely reporting details: they shape how confidently readers can interpret precision and potential bias. The case highlights why transparent endpoint definitions, analysis plans, participant flow, and clear treatment descriptions matter when interpreting clinical trial statistics.
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.
Several trial-specific reporting gaps limit interpretation beyond the uncertainty in the numerical results. Most importantly, the primary endpoint is reported descriptively without an inferential comparison. The endpoint wording also leaves some ambiguity: the title and timeframe concern time to the second stage, while the definition describes the interval from complete dilation to delivery. The exact measurement represented by the reported means is therefore not fully clear.
The dosing descriptions conflict with the arm labels. The group labeled low dose Pitocin is described as receiving an escalating infusion, while the group labeled standard incremental protocol is described as receiving a fixed 2 mius/min infusion. The registry record does not reconcile these descriptions. This makes it difficult to identify the exact intervention contrast from the record alone.
Although enrollment is listed as 121, primary endpoint counts are 57 and 59. The reason for this difference is not reported in the registry record. Participant flow, missing outcome data, exclusions, and the analysis population are not described. The record does not say whether all randomized participants were analyzed according to assigned group.
Statistical methods are also sparse. The registry reports no analyses, no primary comparison, and no sample-size justification for the trial. It does not report adjustment factors, multiplicity handling, interim monitoring, or sensitivity analyses. The secondary results available for recalculation are unadjusted and do not cover all listed outcomes. These limits mean that the posted record supports cautious description, but does not allow a complete evaluation of the planned analysis or the robustness of the findings.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Foley Bulb With Low Dose Pitocin Versus Foley Bulb With a Standard Incremental Infusion Protocol for the Induction of Labor — NCT02150954.
- Registry record last updated 2023-10-26; status last verified 2014-06.
- Results first posted 2014-07-23.
- 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.
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18. Record Summary
The registry describes a completed randomized, unmasked, parallel-group phase 4 trial sponsored by Duke University, with enrollment of 121. It compares Foley bulb induction approaches involving Pitocin. The arm labels and dosing descriptions are inconsistent, and the registry record does not resolve the intended protocol contrast.
The primary endpoint is time to the second stage of labor. Group means and inter-quartile ranges are posted, but a primary between-group analysis is not reported in the registry record. Numeric secondary results are posted for cesarean delivery, uterine hyperstimulation, and birthweight; results for other listed secondary outcomes are not reported. The registry does not describe the analysis population, missing-data handling, or multiplicity strategy. Adverse-event summaries record zero serious and zero other adverse events in both groups, while death values are not reported.