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 ExAblate Treatment of Uterine Fibroids for Fertility Enhancement (NCT00730886), a randomized na study. The primary outcome is Live Birth Rate.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00730886 |
| Phase | NA |
| Condition | Uterine Fibroids, With Unexplained Infertility |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | InSightec |
| Results posted | Yes |
2. Clinical Question
Population
Women with unexplained infertility and uterine fibroids that were not hysteroscopically resectable. The registry describes this as the population of interest; it does not report further eligibility details or participant characteristics.
Intervention
ExAblate 2000, described in the arm information as a non-invasive procedure for fertility enhancement.
Comparator
Myomectomy, described in the arm information as an invasive surgical procedure for fertility enhancement.
Primary question
How did live birth rate compare between the ExAblate and myomectomy groups between the 3 and 9-month post-treatment visits? The registry identifies live birth rate as the primary outcome but does not report a numerical comparison.
The trial was intended to evaluate fertility outcomes after either procedure among women seeking pregnancy. Its registry summary places the comparison in the context of fibroids that may require a procedure other than hysteroscopic removal. The stated objective was to assess both efficacy and safety, with fertility enhancement as the central purpose.
The registry also lists pregnancy rate, term delivery rate, miscarriage rate, time to conception, C-section rate, quality-of-life measures, and a depression scale among secondary outcomes. These outcomes cover different aspects of pregnancy and health, but their presence in the registry does not establish that results were collected or reported for each one.
Enrollment did not reach the target number of subjects needed to achieve target power, according to the primary outcome description. The record further says enrollment was insufficient to produce statistically reliable results. Thus the research question is clear, but the posted record does not support a dependable estimate of the difference in live birth rate between the procedures.
3. Trial Design
The registry describes a randomized, parallel-group study with no masking. Participants were assigned to ExAblate 2000 or myomectomy. The record classifies the phase as NA. The listed enrollment is 2, and the study status is terminated.
The intervention arms represent distinct procedures: ExAblate is described as non-invasive, while myomectomy is described as invasive surgery. Randomization is intended, in general, to make treatment groups comparable at the start of a study by using chance to assign participants. It does not ensure balance in every small trial, and the registry does not provide enough participant-level information to assess balance in this study.
The registry lists a study start of 2008-07 and a primary completion of 2011-07. It does not report the reason for termination, the timing of termination, or how many participants were assigned to each arm in the enrollment description. Although enrollment is listed as 2, the primary outcome description explicitly says that enrollment did not reach the target needed for the intended power and was insufficient for statistically reliable results.
The primary outcome was live birth rate, assessed between the 3 and 9-month post-treatment visits. Secondary outcomes included pregnancy and delivery outcomes, time to conception, C-section rate, and patient-reported measures. The registry lists 10 outcome measures, but it does not provide analysis records; the number of analyses listed is 0.
Masking was absent. In general, lack of masking can affect treatment experiences, reporting, and outcome assessment, particularly for outcomes involving judgment or self-report. The registry does not describe the outcome-assessment procedures, so the extent to which this concern applies to any specific measure 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
| Stage | ExAblate Treatment: | Myomectomy Treatment: |
|---|---|---|
| STARTED | 2 | 0 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 2 | 0 |
Reasons for not completing this period:
| Reason | ExAblate Treatment: | Myomectomy Treatment: |
|---|---|---|
| Lost to Follow-up | 1 | 0 |
| Physician Decision | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: enrollment in the clinical trial did not reach the target number of subjects needed to achieve target power and was insufficient to produce statistically reliable results.
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: Study was terminated due to lack of enrollment
| Characteristic | Unit | ExAblate Treatment: | Myomectomy Treatment: | Total |
|---|---|---|---|---|
| Participants analysed | 2 | 0 | 2 | |
| Age, Categorical: <=18 years | Participants | 0 | — | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 2 | — | 2 |
| Age, Categorical: >=65 years | Participants | 0 | — | 0 |
| Sex: Female, Male: Female | Participants | 2 | — | 2 |
| Sex: Female, Male: Male | Participants | 0 | — | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | — | 0 |
| Race (NIH/OMB): Asian | Participants | 1 | — | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | — | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | — | 0 |
| Race (NIH/OMB): White | Participants | 1 | — | 1 |
| Race (NIH/OMB): More than one race | Participants | 0 | — | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | — | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Live Birth Rate, measured over Between the 3 and 9-month post-treatment visits.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
Live birth rate is the primary endpoint. It concerns the occurrence of a live birth among participants in the trial, with the registry specifying an assessment window between the 3 and 9-month post-treatment visits. The record gives no unit, statistical parameter, dispersion measure, or fuller endpoint definition.
Live birth is used in fertility research because it captures an outcome beyond conception or pregnancy: it indicates that a pregnancy resulted in a live birth. As a general statistical point, choosing a primary endpoint helps focus a trial's main comparison and limits the risk of treating many outcomes as equally central. The endpoint's clinical meaning, however, depends on its precise definition, measurement window, and analysis population.
In this record, the window is stated, but details such as how pregnancies spanning the visit period were handled, whether births were confirmed through records, and how participants without follow-up were treated are not reported in the registry record. No numerical live birth result, group-specific rate, effect estimate, confidence interval, or p-value is reported. The registry states that enrollment was insufficient to produce statistically reliable results, which limits what can be concluded from the primary endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a randomized comparison of ExAblate 2000 with myomectomy and names live birth rate as the primary outcome. It does not report a numerical live birth result for either group or a comparative effect estimate. Consequently, the direction and size of any difference in the primary outcome cannot be established from the posted results.
The registry's own primary outcome description is important for interpretation: enrollment did not reach the target number of subjects needed to achieve target power and was insufficient to produce statistically reliable results. The listed enrollment is 2. That enrollment is too limited, by the registry's account, to support a dependable estimate of comparative fertility outcomes. A lack of a reported statistically reliable result should not be interpreted as evidence that the procedures have equivalent outcomes.
No confidence interval or p-value for the primary comparison is reported. In general, a confidence interval communicates the range of effects compatible with the data under the analysis assumptions; with limited information, an estimate may be imprecise. Since no effect estimate or interval is posted, the uncertainty cannot be quantified from the registry record.
The registry lists 10 outcome measures, including pregnancy, term delivery, miscarriage, time to conception, C-section rate, and patient-reported measures. It does not provide outcome results for those measures in the record. The primary outcome was not reduced to a single comparison because it has several categories or time points, according to the registry note. This means there is no one simplified primary comparison available to interpret from the posted data.
The safety information is also limited. The record lists adverse-event counts for the ExAblate group and zeros for the myomectomy group, but the myomectomy group is listed with 0 at risk in those categories. Those entries do not support a balanced comparison of safety between procedures. The record does not provide enough information to determine the completeness of event collection or the follow-up time for adverse events.
Overall, the registry supports describing the study's question, design, and limitations, but not estimating comparative efficacy or safety. The record's statement about insufficient enrollment should take precedence over any attempt to treat sparse counts as a reliable treatment comparison.
9. Statistical Methods Explained
Random assignment and parallel groups. In a randomized trial, assignment by chance is intended to reduce systematic differences between treatment groups at baseline. A parallel design means that participants are assigned to one of the treatment arms rather than receiving both treatments in sequence. These features describe the design, not the quality or precision of the evidence. With enrollment listed as 2, chance assignment cannot be expected to guarantee that important participant characteristics are balanced. The registry does not report baseline characteristics or allocation details beyond the randomized, parallel classification.
What does an outcome comparison estimate?
In general, a comparative analysis estimates how an outcome differs between assigned groups, according to a specified outcome definition and analysis population. For a binary outcome such as whether a live birth occurred, an analysis might report group-specific proportions and a measure of their difference or relative relationship. The record does not report those results, so no such estimate can be interpreted for this trial. No unadjusted or adjusted primary analysis is listed.
The registry names a period between the 3 and 9-month post-treatment visits for the primary outcome. A defined time window is important because outcomes can change with follow-up duration. However, the record does not explain how the visit window was applied, how participants who missed visits were handled, or whether the primary outcome was analyzed by assigned group. Those details are not reported in the registry record.
Why does precision matter?
Precision describes how much uncertainty surrounds an estimate. A confidence interval is a general way to express this uncertainty: narrower intervals indicate greater precision, while wider intervals indicate less precision under the model assumptions. No interval is reported for the primary outcome. The registry explicitly says enrollment was insufficient to produce statistically reliable results, so the record itself warns against reading the study as a precise estimate of comparative effects.
A p-value, when reported, summarizes how incompatible observed data are with a specified statistical null model; it does not measure the size or importance of an effect. No primary-outcome p-value is reported. It would therefore be inappropriate to infer statistical significance or non-significance from the adverse-event entries or the enrollment figure.
What do the planning assumptions mean?
The record includes a general sample-size planning description based on an observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not a description of the trial's actual analysis, and the registry does not report a sample-size justification or actual achieved power calculation. A planning illustration is not observed power and does not repair the lack of reliable outcome information.
In general, planning around a fraction of an observed effect asks how many participants might be needed to detect a smaller target effect than the observed one, under the stated assumptions. Such illustrations depend on the effect estimate and model assumptions used. They do not establish that a future or current trial has that power, nor do they show that the hypothesized effect is true. The registry does not report enough primary-outcome results to assess how well a planning illustration corresponds to this study.
Why can sparse data be difficult to analyze?
When outcomes are rare or only a few participants are observed, conventional estimates can be unstable and uncertainty can be substantial. General methods may use exact procedures or models designed for sparse outcomes, but the appropriate method depends on the outcome and analysis plan. The registry does not identify an analysis method for live birth rate, nor does it report model specifications, covariate adjustment, or an analysis plan. No method should be attributed to the investigators without that information.
For count outcomes, over-dispersion is a general concern when variability exceeds what a simple count model assumes. It can affect standard errors and confidence intervals. The registry does not report a count-based primary analysis or data needed to assess over-dispersion, so this issue cannot be evaluated for the primary outcome.
The registry lists 0 analyses. This means the record does not contain analysis entries from which to assess whether outcomes were tested as planned, whether any model assumptions were checked, or how missing data were handled. It does not establish that no analyses were ever performed outside the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 10 outcome measures. These include the primary live birth rate and secondary pregnancy, delivery, time-to-conception, symptom, quality-of-life, and depression outcomes. Testing multiple outcomes can increase the chance of obtaining an apparently notable finding by chance if no adjustment or hierarchy is used. As a general statistical principle, a prespecified primary outcome can help identify the main comparison, while secondary outcomes may be exploratory or require a plan for multiplicity.
Any multiplicity adjustment, outcome hierarchy, or prespecified method for interpreting the secondary outcomes is not reported in the registry record. The record lists 0 analyses, so it does not provide results or information about which outcomes were analyzed. No conclusion about multiple-testing control can be drawn.
Missing-data methods are also not reported in the registry record. The record does not state how participants with incomplete follow-up, missing outcome assessments, or pregnancy outcomes not observed within the specified window were handled. It does not give an analysis population definition, such as whether analyses were based on randomized assignment or on participants with available outcome data. These omissions matter because excluding participants or making assumptions about unobserved outcomes can change both an estimate and its uncertainty.
The primary outcome description says enrollment was insufficient to produce statistically reliable results. Sparse enrollment and unreported analysis details make it especially important not to infer a complete outcome analysis or a multiplicity strategy from the list of registered measures alone.
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 |
|---|---|---|---|
| ExAblate Treatment: | 1 | 2 | 50.0% |
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 |
|---|---|
| ExAblate Treatment: | 1 of 2 |
| Myomectomy Treatment: | 0 of 0 |
Most frequent serious adverse event terms
| Event term | Organ system | ExAblate Treatment: | Myomectomy Treatment: |
|---|---|---|---|
| perinatal fever | Pregnancy, puerperium and perinatal conditions | 1 of 2 | 0 of 0 |
Most frequent non-serious adverse event terms
| Event term | Organ system | ExAblate Treatment: | Myomectomy Treatment: |
|---|---|---|---|
| blood tinged mucus peri-rectum | Skin and subcutaneous tissue disorders | 1 of 2 | 0 of 0 |
Serious events with the highest arm-level rate: perinatal fever (50.0%).
The registry lists serious adverse events for the ExAblate treatment group with 2 at risk and 1 affected. For other adverse events, it lists 2 at risk and 1 affected. The Myomectomy Treatment group is listed with 0 at risk and 0 affected in both categories. The record identifies perinatal fever as the top serious term and reports 50.0% for that term.
These entries should not be read as a comparative safety estimate. In particular, the myomectomy group is listed with 0 at risk, so its zero affected count does not represent an observed event-free group with participants under observation. The record does not explain why the group is listed that way, and the reason is not reported in the registry record.
Adverse-event counts describe recorded events within the registry's reporting framework; they do not, by themselves, establish that an event was caused by a procedure. The record does not report event definitions, duration of safety follow-up, severity details beyond the serious/other categories, or completeness of collection. The small enrollment and limited group information mean the listed counts should be treated as descriptive registry entries, not evidence that one procedure is safer than the other.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, parallel-group study was registered to compare ExAblate 2000 with myomectomy for fertility enhancement in women with unexplained infertility and uterine fibroids. It identifies live birth rate as the primary outcome and gives an assessment window between the 3 and 9-month post-treatment visits. It also records that enrollment was 2 and that the study was terminated.
What the record does not establish is a numerical comparative effect on live birth or the other listed outcomes. It reports no group-specific live birth results, effect estimate, confidence interval, or p-value. The registry explicitly states that enrollment did not reach the target needed to achieve target power and was insufficient to produce statistically reliable results. The absence of a reliable comparison is not evidence that the procedures have the same outcomes.
The study's registered aims and the outcomes it intended to examine remain relevant to understanding the research question. But a trial's purpose is not itself a finding. Without reported outcome estimates and their uncertainty, readers cannot determine the direction, magnitude, or precision of differences between the assigned groups from this record.
The adverse-event entries likewise do not permit a meaningful safety comparison, particularly because the Myomectomy Treatment group is listed with 0 at risk. The record does not give sufficient information to interpret the zeros as evidence of no events under comparable observation.
Accordingly, the most defensible reading is that the registry documents an attempted randomized comparison that ended with enrollment too limited, by the record's own description, to yield statistically reliable results. It cannot establish that either procedure improves fertility, is equivalent to the other, or has a comparative safety advantage.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates the difference between a clinically important question and an informative estimate. The registry asks whether two procedures differ in fertility outcomes for women with unexplained infertility and uterine fibroids. It identifies live birth rate as the primary endpoint, a direct outcome for the stated fertility objective. Yet the registry also says that enrollment was insufficient to produce statistically reliable results.
Randomization is valuable in comparative research because it can reduce systematic confounding, but randomization alone does not guarantee useful precision. A very limited enrollment can leave estimates unstable and uncertain, even when the question and design are clearly stated. This distinction is important: a trial may have a randomized design without providing evidence precise enough to resolve its primary comparison.
The registry also demonstrates why results need to be interpreted alongside outcome definitions, follow-up, analysis methods, and missing-data handling. The primary assessment window is recorded, but details of the endpoint definition and analysis population are not. The record lists secondary outcomes but no analysis entries. Without results and methods, readers cannot assess the magnitude of observed effects, their uncertainty, or how multiple outcomes were handled.
Finally, the adverse-event entries show how denominators shape interpretation. A zero count in a group listed with 0 at risk cannot be treated as equivalent to zero events among participants observed for safety. Reporting who was at risk and how outcomes were collected is essential to meaningful safety comparisons.
The statistical lesson is not a conclusion about which procedure is preferable. It is that design labels and registered outcomes do not substitute for complete, interpretable outcome data. The registry's warning about insufficient enrollment should guide interpretation of the entire record.
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 most consequential limitation recorded by the trial is that enrollment did not reach the target number of subjects needed to achieve target power and was insufficient to produce statistically reliable results. The registry lists enrollment as 2. It does not report the target enrollment or the reason enrollment fell short. The study is marked terminated, but the reason for termination is not reported in the registry record.
No numerical result is reported for the primary live birth outcome. The registry does not provide group-specific rates, an effect estimate, uncertainty intervals, or a p-value. It also notes that the primary outcome has several categories or time points and was not reduced to one comparison. The details of those categories or time points are not reported in the registry record.
The record lists no analysis entries. It does not report the statistical analysis plan, sample-size justification, allocation details beyond randomization, analysis populations, missing-data methods, or handling of multiple outcomes. Masking is listed as none, but procedures for outcome assessment are not described. Participant characteristics and baseline comparability are also not reported in the registry record.
Safety interpretation has additional constraints. The myomectomy group is listed with 0 at risk and 0 affected for the serious and other adverse-event categories. The registry does not explain these entries or provide enough detail to assess completeness and duration of safety follow-up. The adverse-event information therefore cannot support a balanced between-group comparison.
These limitations concern the information available in the registry record. They do not establish whether additional analyses or data exist outside the record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: ExAblate Treatment of Uterine Fibroids for Fertility Enhancement — NCT00730886.
- Registry record last updated 2018-08-15; status last verified 2018-08.
- Results first posted 2018-08-15.
- 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
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18. Record Summary
This terminated, randomized, parallel-group study compared ExAblate 2000 with myomectomy for fertility enhancement in women with unexplained infertility and uterine fibroids. The registry lists no masking and phase NA. Enrollment was 2; the listed study start was 2008-07 and primary completion was 2011-07.
Live birth rate was the primary outcome, assessed between the 3 and 9-month post-treatment visits. The registry states that enrollment did not reach the target needed for target power and was insufficient to produce statistically reliable results. No numerical primary-outcome comparison or analysis entries are reported.
The registry lists 10 outcome measures and adverse-event counts, but the posted information does not support a reliable comparative conclusion about fertility outcomes or safety. The myomectomy adverse-event group is listed with 0 at risk, limiting interpretation of its zero counts.