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 Misoprostol Prior to Intrauterine Device (IUD) Insertion in Nulliparous Women (NCT01147497), a randomized na study. The primary outcome is Provider Perceived Ease of Insertion on a 100 Point Visual Analogue Scale.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01147497 |
| Phase | NA |
| Condition | Contraception |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 78 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Emory University |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerns nulliparous women having an intrauterine device (IUD) insertion. The registry lists contraception as the condition and records enrollment of 78 participants. Further eligibility details, such as age range or exclusions, are not reported in the registry record.
Intervention
The intervention was misoprostol, with the arm description specifying 400mcg taken buccally 2 hours before the IUD insertion visit. The clinical question is whether cervical priming before the procedure is associated with an easier insertion as rated by the provider.
Comparator
The comparison was a placebo pill described as identical to the study drug in appearance, taste, and smell. It was taken buccally 2 hours before the insertion visit. The registry identifies the study as randomized and triple-masked, but does not identify which groups of people were masked.
Primary question
The primary endpoint was provider-perceived ease of insertion, recorded immediately after IUD insertion on a 100-point visual analogue scale. The scale runs from 0, meaning most ease, to 100, meaning most difficult. The posted medians were 21.0 in each arm. These summaries describe the central ratings; they do not, by themselves, establish whether the distributions differed.
3. Trial Design
The registry describes a randomized, triple-masked, parallel-group trial sponsored by Emory University. It records enrollment of 78 and a completed status. The study start is listed as 2010-06, and primary completion is listed as 2011-09. The phase is recorded as NA. The registry record does not give further details about the randomization sequence, allocation concealment, or the people included in triple masking.
Participants were assigned to misoprostol or placebo. The misoprostol arm description specifies 400mcg taken buccally 2 hours before the IUD insertion visit. The placebo was described as identical to the study drug in appearance, taste, and smell, and was taken by the same route and at the same time before the visit. The parallel design means the two groups received their assigned study treatment rather than crossing over between treatments, as described in the registry.
The primary endpoint was assessed immediately after insertion. The posted primary outcome includes 35 participants in the misoprostol arm and 36 in the placebo arm. Other posted outcomes have their own denominators. The reasons that endpoint denominators differ from the recorded enrollment are not reported in the registry record. The record does not report a sample-size justification, a detailed statistical analysis plan, or whether interim analyses were planned or conducted.
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: Seventy-eight nulliparous women were enrolled, and 71 completed the study. Five dropped out prior to randomization and method insertion choosing other birth control options.
Overall Study
| Stage | Misoprostol | Placebo |
|---|---|---|
| STARTED | 37 | 36 |
| COMPLETED | 35 | 36 |
| NOT COMPLETED | 2 | 0 |
Reasons for not completing this period:
| Reason | Misoprostol | Placebo |
|---|---|---|
| failed insertion | 2 | 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 | Misoprostol | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 37 | 36 | 73 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 37 | 36 | 73 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 26.05 (SD .554) | 25.5 (SD .554) | 25.775 (SD .554) |
| Sex: Female, Male: Female | Participants | 37 | 36 | 73 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 37 | 36 | 73 |
6. Primary Endpoint
The registry lists the primary outcome as Provider Perceived Ease of Insertion on a 100 Point Visual Analogue Scale, measured over assessed immediately post IUD insertion.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | units on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the provider’s perceived ease of IUD insertion, recorded immediately after the procedure on a 100-point visual analogue scale. The scale is anchored at 0 for most ease and 100 for most difficult. A lower score therefore represents a more favorable ease rating on this measure, while a higher score represents greater perceived difficulty.
This outcome captures the provider’s assessment of the insertion procedure, rather than the patient’s pain rating or overall experience. It is relevant to the trial’s stated aim of evaluating whether misoprostol before insertion eases the procedure. Patient-perceived pain, adjunctive measures, procedure time, acceptability, and other outcomes were listed separately as secondary measures; they are not interchangeable with the provider-rated primary endpoint.
The registry reports the primary result as a median and full range for each arm. A median describes the middle of the ordered observations and is less affected by extreme scores than an arithmetic mean. A full range describes the lowest and highest observed values, but does not show how observations are distributed between those endpoints. The median was 21.0 in both arms. The ranges were 0.0 to 100.0 for misoprostol and 0.0 to 68.0 for placebo. The record does not report an inferential comparison for this primary endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary summaries give a median provider-rated ease score of 21.0 for misoprostol and 21.0 for placebo. On this scale, lower scores indicate greater perceived ease. The equal medians mean that the reported central score is the same in the two arms. They do not establish that all participant ratings, or the full distributions of ratings, were alike.
The full ranges add information about the observed spread. Scores in the misoprostol arm ranged from 0.0 to 100.0, while scores in the placebo arm ranged from 0.0 to 68.0. A range is determined by only the minimum and maximum observations and does not indicate how frequently values occurred between them. In particular, it cannot substitute for a standard deviation, interquartile range, or a distribution plot. Those additional summaries are not reported for the primary endpoint.
The posted primary endpoint has 35 participants in the misoprostol arm and 36 in the placebo arm. The registry record does not report a formal statistical comparison, confidence interval, or p value for this outcome. Consequently, the medians and ranges are descriptive evidence only; they do not quantify the precision of an estimated between-arm difference or establish whether any difference in the underlying outcome is compatible with chance variation.
One secondary outcome reports use of adjunctive measures, including ultrasound guidance or cervical dilation. It records 7 participants in the misoprostol arm and 3 in the placebo arm. The posted risk difference is 0.106, with a confidence interval from -0.049 to 0.261, and an unadjusted p value of 0.188. The confidence interval includes zero, so the estimate is compatible with no difference as well as with differences in either direction under the stated comparison. The interval is broad enough that this result does not precisely determine the size of any difference. It is a secondary outcome and should not be treated as replacing the primary endpoint.
The record does not report an analysis for the primary outcome or reported analyses for the secondary outcomes. The descriptive results and one posted secondary comparison therefore do not provide a complete inferential account of the trial. They describe the outcomes recorded in the registry, while leaving uncertainty about analysis choices, missing observations, and the broader pattern of endpoint results.
9. Statistical Methods Explained
The primary outcome is summarized using a median and full range. These are descriptive statistics: they describe the observed ratings, but do not themselves estimate the precision of a treatment contrast. The registry record does not report a test, confidence interval, or p value for the primary outcome, so the posted summaries cannot be used to infer statistical significance.
What does a median describe?
In general, a median is the middle value after observations are ordered. It gives a measure of central location that is not pulled toward extreme observations in the way a mean can be. Here, the median is 21.0 in each treatment arm. Identical medians do not imply identical distributions: the values around the middle could differ, and the tails could differ. The reported ranges give only the minimum and maximum observed score in each arm. They do not indicate how many ratings lie near either endpoint or how concentrated the remaining ratings are.
How should the secondary risk difference be read?
The adjunctive-measures outcome is reported as a count of participants in each arm and as a risk difference. A risk difference expresses the difference between the event proportions in the two groups, using the direction defined by the comparison. The posted estimate is 0.106 for misoprostol relative to placebo. A positive estimate in that direction indicates a higher observed proportion in the misoprostol arm for this outcome; it is not a statement about the primary ease rating.
The confidence interval for the risk difference extends from -0.049 to 0.261. In general, a confidence interval represents the range of estimates reasonably compatible with the data under the method used, and its width conveys precision. Because this interval includes zero, the posted data do not rule out a null risk difference at the interval’s confidence level. Its endpoints also allow for effects in either direction, so the estimate should not be read as a precise measure of the difference.
The unadjusted p value for this secondary comparison is 0.188. In general, a p value describes how unusual data at least as incompatible with a specified null hypothesis would be if that hypothesis and the analysis assumptions held. It is not the probability that the null hypothesis is true, nor does it measure the clinical importance of an estimate. The registry does not report a multiplicity adjustment for this result, so the p value should be read as unadjusted.
What do the planning illustrations represent?
The registry’s planning illustration is based on the observed effect, not on the trial’s original design. It uses a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation. The illustration considers detecting stated fractions of the observed effect and gives participants per arm for 80% power and participants per arm for 90% power. These are hypothetical planning quantities, not observed trial results and not observed power. They do not show that the completed trial had a particular probability of detecting an effect.
In general, planning calculations depend on the effect chosen for detection and on assumptions about the outcome and analysis. An effect smaller than the observed estimate requires a different planning scenario than the full observed estimate. The registry does not report the trial’s own sample-size justification or the assumptions used when enrollment was planned. The planning illustration therefore cannot be treated as evidence of the original design rationale.
What analysis details remain unknown?
The registry record does not report the statistical method used to compare the primary endpoint, whether any adjustment was planned, or how missing outcome data were handled. It also does not report whether the primary analysis followed an intention-to-treat principle or used another analysis population. For the posted secondary risk difference, the registry gives an unadjusted comparison but does not describe the method used to construct the confidence interval or calculate the p value. Statistical interpretation should stay within those limits rather than assuming an analysis procedure that is not recorded.
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 specifying how the outcomes were prioritized beyond that labeling. It also does not report whether hypotheses for secondary endpoints were prespecified in detail, whether interim analyses were planned, or whether any method was used to account for testing multiple outcomes. The record reports zero analyses in its analysis listing, while posting outcome summaries and one secondary comparison. Those details do not establish what analyses may have been conducted outside the registry record.
Multiplicity matters because repeated statistical testing can increase the chance that at least one result appears noteworthy even when there is no corresponding effect. An unadjusted p value addresses its individual comparison under its assumptions; it does not account for the other outcomes tested. The posted p value of 0.188 is unadjusted. No correction or family-wise testing strategy is reported, so no multiplicity-adjusted interpretation can be attributed to the record.
Missing-data handling is also not reported. The primary endpoint has 35 participants in the misoprostol arm and 36 in the placebo arm, while the registry records enrollment of 78. The adjunctive-measures outcome has 37 and 36 participants, respectively. These endpoint denominators differ, but the reasons are not reported in the registry record. It does not say whether observations were unavailable, excluded, or otherwise not included in each outcome summary.
The record does not define the analysis population or explain how participants were handled after randomization if an outcome was missing. It is therefore not possible to determine whether the posted analyses used all randomized participants, only participants with recorded outcomes, or another population. No imputation method or sensitivity analysis is reported. These gaps limit assessment of potential bias and the robustness of the results.
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 |
|---|---|---|---|
| Misoprostol | 0 | 37 | 0.0% |
| Placebo | 0 | 36 | 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 |
|---|---|
| Misoprostol | 0 of 37 |
| Placebo | 0 of 36 |
The adverse-event record lists 37 participants at risk in the misoprostol group and 36 in the placebo group. It records 0 serious adverse events in each group and 0 other adverse events in each group. These figures describe the posted counts in the groups at risk; they do not establish that no events occurred outside the recorded categories or observation period.
The registry record does not report deaths for these groups. It also does not provide event descriptions, follow-up duration, severity grading beyond the serious-versus-other categories, or information about how adverse events were collected. The listed counts should therefore be interpreted as a limited registry summary rather than a complete account of safety monitoring.
A zero count in a trial does not demonstrate that an event is impossible or that the underlying risk is zero. In general, the ability to characterize uncommon events depends on the amount and duration of observation, as well as complete ascertainment. Those details are not reported in the registry record. The figures are descriptive and should not be used alone to draw broad safety conclusions.
12. What the Result Does, and Does Not, Mean
The posted primary result describes provider ratings of insertion ease on a scale where lower scores mean greater ease. The median is 21.0 in both arms, and the ranges differ. This is evidence about the observed ratings recorded for the primary endpoint. Because the record does not report an inferential comparison or confidence interval for that endpoint, it does not establish the precision of a between-arm contrast.
The secondary adjunctive-measures result describes observed counts and a risk-difference estimate with an interval that includes zero. It does not establish a definitive difference, and it concerns a distinct outcome rather than the provider-rated ease endpoint. Other secondary outcomes are listed, but their results are not reported in the registry record. The available results therefore do not resolve every question the study set out to examine.
These findings do not establish that misoprostol improves, worsens, or has no effect on IUD insertion experience. A failure to report a primary inferential analysis is not evidence that the treatments are equivalent. Equivalence or noninferiority would require a defined margin and an analysis designed to address that question; such information is not reported in the registry record.
The trial record also does not report enough information to assess the original sample-size rationale, missing-data procedures, or the analysis population. The enrollment and endpoint denominators provide context, but the record does not explain differences among them. These limitations matter when judging how broadly the descriptive results can be generalized or how precisely they estimate outcomes beyond the observed participants.
The appropriate reading is narrow: the record reports equal primary medians, the stated ranges, a secondary count comparison, and zero recorded adverse-event counts in the listed categories. It does not provide a complete analysis of all registered endpoints or a basis for medical advice.
13. Why This Trial Matters Statistically
This trial illustrates the distinction between an outcome summary and a treatment-effect analysis. The primary result gives medians and ranges for each randomized arm, but no reported comparison or interval estimate. Readers can describe the observed central ratings, yet cannot infer the precision of an estimated difference from the medians alone. This distinction is important in clinical research: a numerical summary is not automatically evidence about how much uncertainty surrounds a group contrast.
The example also shows why endpoint type matters. Provider-perceived ease is measured on a 100-point scale, while use of an adjunctive measure is recorded as a participant count and compared as a risk difference. These measures answer different questions and have different statistical interpretations. A result on one endpoint should not be generalized to pain, procedure time, acceptability, or safety without reported evidence for those outcomes.
Another statistical issue is incomplete reporting. The registry identifies multiple secondary outcomes, but results and analyses for most are not reported in the registry record. It gives one unadjusted secondary comparison without a documented multiplicity strategy. This makes it difficult to distinguish a planned confirmatory analysis from exploratory results or to understand how uncertainty across the full set of outcomes was handled.
Finally, planning calculations based on an observed effect are not a substitute for the trial’s original design assumptions. Such illustrations can show how hypothetical sample sizes vary with the effect chosen for detection, but they do not describe observed power and do not establish why the trial enrolled its recorded number of participants. The record’s omissions make that distinction especially important.
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.
A key limitation is that the primary endpoint is reported descriptively, without an inferential comparison or confidence interval in the registry record. Equal medians do not show that the complete score distributions are equal, and the full ranges alone do not describe the distribution’s shape. The record does not provide additional measures of spread for the primary outcome.
The registry records enrollment of 78, while the primary endpoint lists 35 participants in the misoprostol arm and 36 in the placebo arm. Other outcomes have different denominators. The reasons for these differences are not reported. Without an account of missing observations, exclusions, or analysis populations, it is not possible to judge whether the posted summaries represent all randomized participants or assess the impact of missing data.
The trial’s design is described as randomized and triple-masked, but details of sequence generation, concealment, and who was masked are not reported. The registry also does not report the original sample-size justification, a complete statistical analysis plan, interim-analysis plans, or the handling of multiplicity. These omissions limit evaluation of potential bias and the extent to which the reported outcomes reflect prespecified analyses.
The scope of the available results is another limitation. Several secondary outcomes are named, but the registry record does not report their results or analyses. The safety summary reports zero events in the listed categories but lacks event descriptions and follow-up details. Finally, eligibility criteria and participant characteristics beyond the nulliparous population are not reported, limiting assessment of how closely other populations resemble those studied.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Misoprostol Prior to Intrauterine Device (IUD) Insertion in Nulliparous Women — NCT01147497.
- Registry record last updated 2018-01-12; status last verified 2018-01.
- Results first posted 2014-03-24.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry record describes a completed randomized, triple-masked, parallel-group trial sponsored by Emory University. Enrollment was 78. The study start is listed as 2010-06 and primary completion as 2011-09. The phase is recorded as NA.
The trial compared misoprostol 400mcg taken buccally 2 hours before IUD insertion with an identical-appearing, tasting, and smelling placebo taken on the same schedule. The primary endpoint was provider-perceived ease immediately after insertion, scored from 0 for most ease to 100 for most difficult. The posted median was 21.0 in each arm; the primary outcome has no reported inferential comparison in the registry record.
The record lists secondary outcomes covering pain, adjunctive measures, procedure time, acceptability, and additional pain medication, among other measures. Results for most are not reported in the registry record. The adverse-event summary lists 0 serious and 0 other adverse events in each group; deaths are not reported.