Self-administered Lidocaine Gel for Pain-control During Cervical Preparation for Dilation and Evacuation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Self-administered Lidocaine Gel for Pain-control During Cervical Preparation for Dilation and Evacuation (NCT02852434), a randomized phase 3 study. The primary outcome is Pain Perceived at the Time of Laminaria or Osmotic Dilator Insertion.

2. Clinical Question

3. Trial Design

The registry describes a completed, phase 3 randomized controlled trial with a parallel-group model and no masking. Stanford University was the sponsor. The record lists an enrollment of 72. The study compared self-administered vaginal lidocaine gel (2%) with provider-administered lidocaine (1%) by paracervical injection during cervical preparation for dilation and evacuation.

The assigned approaches differed in more than the medication route. Gel was inserted by the participant 15 minutes before cervical preparation; the injection was administered by a provider immediately before tenaculum placement. The comparison therefore evaluates these two approaches as implemented, rather than isolating the effect of lidocaine from the delivery process or timing.

The primary analysis included participants who completed the protocol. Posted primary-outcome summaries list 34.0 participants in the gel arm and 35.0 in the paracervical-block arm. The registry record does not report a participant-flow account explaining the relation between the enrollment figure and the outcome analysis groups. It also does not report additional details of sequence generation, allocation concealment, or the original sample-size rationale.

The registry lists pain management and cervical preparation as conditions. It records study start in 2016-07, primary completion in 2017-04, and status as completed. These design features establish the broad comparison and its setting, but they do not answer questions about operational details that 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants who completed the protocol are included in the analysis.

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: Participants who completed the protocol are included in the analysis.

6. Primary Endpoint

The registry lists the primary outcome as Pain Perceived at the Time of Laminaria or Osmotic Dilator Insertion, measured over Intraoperative; Immediately (0-30 seconds) following cervical dilation.

The primary endpoint was pain perceived at the time of laminaria or osmotic dilator insertion. Pain was measured immediately after cervical dilation, within the stated intraoperative timeframe of 0-30 seconds. The measurement used a 100 mm visual analogue scale, expressed as units on a 0-100 scale. Lower scores correspond to less pain and higher scores to more pain.

A visual analogue scale is a way to record a participant’s subjective assessment along a continuous range. For a continuous endpoint, reporting the group mean describes the average score, while the standard deviation describes how spread out individual scores are around that average. These quantities answer different questions: a mean difference concerns average scores between groups, whereas a standard deviation concerns variation among participants within a group.

The endpoint is directly related to the study’s question because it captures pain at the procedural moment the trial designated as primary. Its immediate timing also makes clear that it is not a measure of pain across the whole procedure or over a longer follow-up period. The registry record does not report additional details about the scale’s administration beyond the stated measurement and timing.

As a subjective measure, a pain score can reflect a participant’s experience and expectations as well as the procedural event. The no-masking design is relevant when interpreting a self-reported outcome: participants knew which approach they received. This does not invalidate the measure, but it is part of the context for understanding what the comparison can establish.

7. Results Posted in the Registry

• Paracervical Block: mean 56.30 versus 48.40 on control; difference 7.90 (95% CI -5.09 to 20.89), standardized effect d = 0.29; z-test p = 0.233.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Anticipated Pain Measured by Visual Analogue Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Paracervical Block: mean 58.70 versus 47.20 on control; difference 11.50 (95% CI 2.00 to 21.00), standardized effect d = 0.57; z-test p = 0.018.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Paracervical Block than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Baseline Pain Measured by Visual Analogue Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Paracervical Block: mean 6.60 versus 2.60 on control; difference 4.00 (95% CI -14.78 to 22.78), standardized effect d = 0.10; z-test p = 0.676.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Paracervical Block and the control. The interval gives the range of effects that remain compatible with the data.

Speculum Placement Measured by Visual Analogue Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Paracervical Block: mean 31.20 versus 24.70 on control; difference 6.50 (95% CI -4.60 to 17.60), standardized effect d = 0.28; z-test p = 0.251.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Paracervical Block and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover different points in the procedural experience: anticipated pain, baseline pain, pain immediately following speculum placement, and overall pain. The registry lists four such measures, while the posted secondary summaries include three. The registry record does not report a posted comparison for overall pain in the secondary outcome summaries.

Across the three posted comparisons, the paracervical-block group mean is higher than the gel group mean. That directional pattern resembles the primary result, but the secondary contrasts do not all provide the same degree of precision. One secondary comparison has an unadjusted p-value of 0.018 and a confidence interval that lies above zero; the other posted intervals include zero. The individual estimates and uncertainties should be read alongside their outcome timing and the primary result, rather than treated as interchangeable measurements of a single endpoint.

Anticipated pain is measured before the procedure, whereas the primary endpoint concerns pain immediately after cervical dilation. A difference in anticipated pain is therefore not itself evidence of a difference in the primary procedural pain endpoint. Baseline and speculum-placement measures also capture different moments. The secondary outcomes add context about several stages, but they do not replace the primary endpoint or resolve its uncertainty.

Unadjusted secondary results carry less weight because multiple outcomes create multiple opportunities for a low p-value to arise even when there is no corresponding underlying effect. In general, multiplicity procedures or a prespecified hierarchy can help manage that interpretive issue. The registry record does not report whether such a procedure was planned or used. The secondary p-values should therefore be treated as exploratory signals rather than as definitive confirmation of the primary comparison.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Anticipated Pain Measured by Visual Analogue Scale
• Baseline Pain Measured by Visual Analogue Scale
• Speculum Placement Measured by Visual Analogue Scale
• Overall Pain Measured by Visual Analogue Scale

9. Statistical Interpretation

10. Statistical Methods Explained

The posted primary outcome is continuous, so its arm summaries use means and standard deviations. A mean is the arithmetic average of participants’ scale scores in an arm. A standard deviation describes the spread of those scores around the mean. Neither statistic alone gives the full shape of the score distribution, and a mean can conceal considerable individual variation.

What does the mean difference represent?

The comparison is expressed as the paracervical-block mean minus the self-administered-gel mean. With this ordering, a positive estimate means the posted average is higher in the block arm, while a negative estimate means it is lower in that arm. Because the scale defines higher scores as more pain, the direction can be related to the scale’s meaning. This is a direction-of-contrast convention, not evidence that an observed difference is important to participants.

The posted primary means are 56.3 and 48.4, and the unadjusted mean difference is 7.9. The comparison also reports a pooled standard deviation of 27.56 and a standardized effect estimate of 0.287. A standardized effect expresses a mean contrast in standard-deviation units, allowing contrasts measured on different scales to be described on a common scale. It does not change the raw-unit interpretation of the mean difference and does not by itself establish clinical importance.

How should a confidence interval be read?

A confidence interval represents uncertainty around an estimate under the assumptions of the method used to construct it. A narrower interval indicates greater precision; a wider one indicates that a broader range of values remains compatible with the data and method. The primary interval, from -5.088 to 20.89, includes zero and values on both sides of zero. This means the estimate alone does not settle the direction of an underlying mean contrast. The registry record does not specify the confidence level or describe the interval-construction method.

What does the p-value add?

The unadjusted p-value is 0.233. In general, a p-value measures how unusual data at least as incompatible with a specified null model would be if that model were true, subject to the analysis assumptions. It is not the probability that the null hypothesis is true, the probability that the observed result occurred by chance, or a measure of the size or importance of an effect. The posted value should be considered together with the estimate and interval, not treated as a stand-alone verdict.

The registry record reports no sponsor-posted analyses in the outcome-analysis entries. The displayed comparison is therefore a simple unadjusted recalculation from the posted summary statistics, rather than a reported adjusted model. No discrepancy between the recalculation and a sponsor analysis is indicated. The record does not report a detailed statistical analysis plan, covariate adjustment strategy, or exact test used by the trial investigators.

Why do standard deviations matter?

Variation within each arm affects how precisely a group contrast can be estimated. When participants’ scores vary widely, the group mean is less representative of each individual score, and a given group size generally yields less precision than it would with less variation. The posted primary standard deviations, 26.0 and 29.0, give context for the mean difference. They should not be confused with standard errors, which describe uncertainty in an estimated mean rather than spread among individual observations.

The arm summaries also report standard errors of 4.459 and 4.902. A standard error reflects the precision of the corresponding mean estimate under the calculation assumptions. It is not a measure of participant-to-participant variation. The registry record does not provide the raw observations, so the distributions, outliers, and other features that might affect interpretation cannot be assessed from these summaries alone.

What does randomization contribute?

Random assignment is intended to reduce systematic differences between groups at allocation. In general, it supports a causal interpretation of the contrast between assigned approaches when the trial is implemented and analyzed appropriately. It does not guarantee that the groups are identical on every characteristic, and it does not address every possible source of bias after assignment. The registry record identifies randomization but does not report allocation concealment or sufficient details to assess its implementation.

No masking was used. For a subjective pain endpoint, knowledge of the assigned approach can be relevant to reporting and measurement. Randomization and open-label measurement are distinct design features: randomization concerns how participants are assigned, while masking concerns awareness of assignment. Both should be considered when judging the strengths and limits of the result.

What can be concluded from these methods?

The statistical summaries describe the observed averages and the uncertainty around their unadjusted contrast. They do not establish the trial’s original design assumptions, the prespecified analysis choices, or the handling of incomplete data. Those details are not reported in the registry record. The most defensible reading stays close to the reported endpoint, timing, arm summaries, and comparison, while keeping the limitations of an unmasked subjective outcome in view.

11. Confidence Intervals and Precision

The primary estimate is a mean difference of 7.9 units, with a confidence interval from -5.088 to 20.89. The interval is broad enough to include a negative difference, zero, and a positive difference. Its lower endpoint is compatible with a mean that is lower in the block arm, while its upper endpoint is compatible with a mean that is higher in that arm. The interval therefore leaves uncertainty about both the direction and magnitude of the underlying contrast.

Precision is not the same as whether a result passes a significance threshold. An estimate can be centered away from zero yet remain uncertain, particularly when the interval covers a range of plausible effects. Conversely, an interval’s width does not tell whether a difference matters clinically. The registry record does not report a threshold for a clinically important difference, so the clinical importance of any particular value within this interval cannot be established from the record.

The unadjusted p-value of 0.233 is consistent with the interval’s inclusion of zero, but the two summaries answer related rather than identical questions. The p-value evaluates compatibility with a null model under analysis assumptions; the interval communicates a range of estimates compatible with the data and method. The registry record does not state the confidence level, so no confidence level should be inferred from the reported endpoints.

The arm standard deviations, 26.0 and 29.0, and the analyzed group sizes, 34.0 and 35.0, provide context for precision. The summaries indicate that individual scores varied within both groups. Without participant-level data, the distribution and influence of unusual observations cannot be examined. These uncertainties reinforce the importance of describing the finding as an imprecise group-average comparison rather than as a definitive account of the experience of all participants.

12. Planning a Similar Trial: Sample Size

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

The planning values are participants per arm, not total participants or total events. The registry’s planning illustration uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It considers effects set at 100%, 75%, and 50% of the observed effect. These are planning assumptions for the illustration; the trial’s original sample-size assumptions are not reported in the registry record.

For planning around 100% of the observed primary effect, the illustration gives 192 participants per arm for 80% power and 256 participants per arm for 90% power. For 75% of the observed effect, it gives 340 participants per arm for 80% power and 455 participants per arm for 90% power. For 50% of the observed effect, it gives 765 participants per arm for 80% power and 1,024 participants per arm for 90% power.

In general, power is the chance that a study would detect an effect of a specified size under the assumed model and testing conditions. The 80% column represents a planning target with an 80% chance of detecting the specified effect; the 90% column represents a higher target. Greater power generally requires more participants when other assumptions are held fixed. Likewise, smaller effects are harder to distinguish from random variation and require more participants, as the progression across the displayed effect assumptions illustrates.

The curve should be read as a visual representation of the same planning relationship: the required sample size depends on the effect size and desired power. These figures are a planning illustration based on the observed effect, not observed power.

13. How the Sample Size Is Derived

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

Formula

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

Worked calculation for this trial

1. Observed difference Δ = 7.900; pooled standard deviation σ = 27.563.
2. n = 2 × (1.96 + 0.842)² × 27.563² / 7.900² = 191.1, rounded up to 192 participants per arm for 80% power.

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

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 7.9                      # observed difference in means
sigma <- 27.5632244718136                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

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

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2852434)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 192 (80% power), 256 (90% power)
 75% of observed effect: n per arm = 340 (80% power), 455 (90% power)
 50% of observed effect: n per arm = 765 (80% power), 1,024 (90% power)
power.t.test: 192.1 
Simulated power at n = 192 per arm: 0.801 (20000 replicates)

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

14. Multiplicity, Missing Data and Analysis Populations

The registry lists several outcome measures, including the primary pain endpoint and secondary pain measures at different times. Testing or comparing multiple outcomes raises a multiplicity issue: when many questions are examined, the chance of at least one apparently notable result can increase. This is a general statistical concern, not a claim that any particular result is false.

The registry record does not report a multiplicity adjustment, a prespecified order for testing outcomes, or a detailed statistical analysis plan. It also does not report whether the trial distinguished confirmatory analyses from exploratory ones. Accordingly, the unadjusted secondary results should not be interpreted as if a family-wise error procedure or other correction had been applied. The displayed unadjusted p-values do not by themselves establish how the investigators intended to handle multiple comparisons.

The record states that participants who completed the protocol were included in the primary analysis. It does not report an intention-to-treat analysis, a per-protocol analysis definition beyond that statement, or how participants who did not complete the protocol were handled. The enrollment figure is 72, while the posted primary outcome summaries list 34.0 and 35.0 in the two arms. The registry record does not report participant flow or explain this difference. No additional participant counts or missingness patterns should be inferred from these summaries.

Methods for missing outcome data are not reported in the registry record. In general, missing data can affect an estimate if participants with unobserved scores differ systematically from those with observed scores. The extent and direction of any such effect depend on the amount, reasons, and pattern of missingness, none of which are described in the record. No imputation or sensitivity analysis is reported.

The record also does not report covariate-adjusted outcome analyses, allocation concealment details, or a protocol-level account of planned analysis decisions. These omissions limit assessment of whether the posted summaries follow prespecified methods. They do not show that particular methods were or were not used outside the registry record; they mean that those details are not reported in the registry record.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports serious adverse events for 0 of 34 participants at risk in the self-administered-gel group and 0 of 35 participants at risk in the paracervical-block group. It also reports other adverse events for 0 of 34 participants at risk in the gel group and 0 of 35 participants at risk in the block group. Deaths are reported as 0 in each group.

These figures mean that no serious or other adverse events, and no deaths, were recorded in the registry’s reported outcome entries for the listed groups. They should not be read as proof that no adverse events could occur, or as a comparison showing that the approaches have identical safety profiles. The registry record does not report additional event descriptions, event severity beyond the serious-versus-other grouping, or follow-up details for these entries.

Adverse-event counts describe what was recorded under the trial’s reporting and observation conditions. With no events reported, the entries do not provide an estimate of the relative frequency of a particular event type. They also do not supply information about unreported events or about safety outside this trial. The figures should be interpreted as registry safety reporting, not as a general safety conclusion.

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

The trial’s primary result is a comparison of mean pain scores at a specific procedural moment. The gel group’s posted mean was 48.4 and the paracervical-block group’s mean was 56.3 on the 0-100 visual analogue scale. The unadjusted mean difference, block minus gel, was 7.9 units, with a confidence interval from -5.088 to 20.89 and an unadjusted p-value of 0.233. The data therefore show a lower observed average in the gel arm, while leaving substantial uncertainty about the underlying difference.

This result does not establish that the approaches are equivalent. Failure to show a clear difference is not the same as evidence that two approaches produce the same outcome. An equivalence conclusion would require a prespecified margin and an analysis designed for that question; neither is reported in the registry record.

Nor does the result prove that one approach is superior. The interval includes values that allow for a difference in either direction, and no threshold for clinical importance is reported. The mean contrast also does not describe every participant’s score. Individual experiences may differ from the group average, and the posted aggregate summaries do not show the distribution of individual responses.

The result applies to the comparison as conducted: self-administered vaginal lidocaine gel inserted 15 minutes before cervical preparation versus provider-administered paracervical lidocaine injection immediately before tenaculum placement. Because administration and timing differed, the trial does not isolate the contribution of any one feature. The open-label design and subjective endpoint are additional interpretive considerations.

Finally, the registry record does not report all details needed to evaluate analysis decisions, missing data, or multiplicity. The posted results support a careful description of the observed group averages and their uncertainty, but they do not justify broader claims beyond the study population, endpoint, and recorded comparison.

17. Why This Trial Matters Statistically

This trial is statistically useful because it makes clear the difference between the direction of an observed estimate and the strength of evidence about the underlying contrast. The mean pain score was lower in the gel arm, but the confidence interval includes zero and extends across values on both sides of it. A point estimate alone can make a comparison sound more certain than it is; the interval puts that estimate in the context of its uncertainty.

The endpoint also illustrates why outcome timing matters. Pain immediately after cervical dilation is not the same measure as anticipated pain before the procedure, baseline pain, or pain after speculum placement. These outcomes may each be informative, but they address distinct moments and should not be blended into a single conclusion.

The open-label design is important for a participant-reported endpoint. Randomization and masking serve different purposes, and this trial had random allocation without masking. The comparison can be described as randomized while still acknowledging that participants knew which approach they received and that the endpoint was subjective.

The record also shows why multiple outcomes need a clear analysis plan. A secondary result with an unadjusted p-value of 0.018 may attract attention, but without reported multiplicity handling or a prespecified hierarchy, it should be interpreted cautiously. Reporting that limitation is part of sound statistical interpretation, not a reason to ignore the outcome.

Finally, planning illustrations based on an observed effect are not retrospective evidence of power. They show how assumptions about effect size and desired power relate to sample requirements. Keeping planning calculations separate from the trial’s observed results helps prevent a common misreading of sample-size displays.

18. 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 endpoint is a subjective visual analogue scale score, and the trial had no masking. Participants knew whether they received self-administered gel or a provider-administered injection. Awareness of assignment can matter when participants report pain, so the score comparison should be interpreted with that design feature in mind.

The assigned approaches also differed in route, administrator, and timing. Gel was self-administered 15 minutes before cervical preparation, while the paracervical injection was provider-administered immediately before tenaculum placement. The trial comparison therefore does not separate the effects of the medication from the experience and timing of its administration.

The primary outcome analysis included participants who completed the protocol. Although the registry reports enrollment of 72, the primary outcome summaries list 34.0 participants in the gel arm and 35.0 in the block arm. The registry record does not report participant flow, reasons for non-completion, or missing-outcome handling. This prevents assessment of whether the analyzed participants differed from those not included in the posted outcome summaries.

The primary confidence interval spans negative and positive values, indicating limited precision about the direction and magnitude of the mean contrast. The record does not report a threshold for clinical importance, so the clinical interpretation of a difference of a particular size cannot be determined from the registry information alone.

The registry record does not report a detailed statistical analysis plan, multiplicity adjustment, or the trial’s original sample-size assumptions. No sponsor-posted outcome analyses are listed. The results therefore warrant interpretation as registry-posted summaries and simple unadjusted recalculations, rather than as a complete account of all trial analyses. The record also does not provide participant-level data, which limits assessment of score distributions and unusual observations.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Self-administered Lidocaine Gel for Pain-control During Cervical Preparation for Dilation and Evacuation — NCT02852434.
• Registry record last updated 2019-06-07; status last verified 2019-06.
• Results first posted 2018-04-17.
• 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.

22. Record Summary

NCT02852434 is a completed, phase 3 randomized controlled trial sponsored by Stanford University. It used a parallel-group model and no masking, with an enrollment of 72. The study compared self-administered vaginal lidocaine gel (2%) with provider-administered lidocaine (1%) by paracervical injection for pain control during cervical preparation for dilation and evacuation.

The primary outcome was pain perceived at dilator insertion, measured immediately after cervical dilation using a 0-100 visual analogue scale. Posted group means were 48.4 for gel and 56.3 for paracervical block. The unadjusted mean difference was 7.9, with a confidence interval from -5.088 to 20.89 and an unadjusted p-value of 0.233.

The registry also lists secondary pain outcomes and adverse-event summaries. The primary analysis population consisted of participants who completed the protocol. Details about participant flow, missing data, the original sample-size rationale, and a full statistical analysis plan are not reported in the registry record.