A Study of Oral Contraception Under Simulated OTC Conditions: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Oral Contraception Under Simulated OTC Conditions (NCT03559010), a na phase 3 study. The primary outcome is Self-selection.

2. Clinical Question

The central research question is about behavior in an OTC-like environment, rather than a comparison of the medication with another treatment. In particular, the study aimed to assess whether consumers selected and used norgestrel 0.075 mg in a manner consistent with OTC package directions. Selection and use are related but distinct: a person can make an appropriate initial selection yet use a product differently from its directions, or make an inappropriate selection and not proceed to use. The listed primary endpoint focuses on selection; listed secondary outcomes address aspects of actual use and product-label precautions.

This distinction matters when interpreting the study's scope. A single-group design can describe behavior within the observed study setting if relevant outcome data are collected and analyzed, but it does not establish how behavior would differ under another condition. Here, the registry record states that no primary endpoint calculations were made. It therefore does not report an estimate of correct self-selection, nor does it answer the main question with a calculated proportion.

3. Trial Design

This is a Phase 3, single-group study of norgestrel 0.075 mg tablets. The registry record lists enrollment as 189 and the study status as terminated. The recorded study start is 2018-04-27, and the primary completion date is 2018-09-09. Those record entries do not supply a primary endpoint result: the endpoint description says the study was terminated before endpoint calculations were made.

The intended setting was an OTC-like environment, described in the official title as a naturalistic environment. The study objective was to assess whether consumers selected and used the product in a manner consistent with OTC package directions. The listed regimen was one tablet orally each day at the same time, for up to 16 weeks. This is a study of behavior surrounding a specific product and its directions, not a comparison between treatment groups.

There is no control arm described. Allocation is recorded as NA, masking as none, and the model as single-group. Thus, the design does not support a randomized, masked, between-group treatment contrast. The registry record does not report a more detailed protocol description, the planned statistical analysis, or a sample-size justification.

The listed outcomes span selection, use, label-related precautions, and safety. Examples include whether users used another hormone-containing birth-control method at the same time, whether they used a barrier method or abstained for the first 48 hours after starting, and whether pregnancies were reported during the study. These are outcome topics, not evidence that corresponding endpoint calculations were completed. The record lists 10 outcome measures and 0 analyses. The trial's termination and the absence of primary endpoint calculations sharply limit what can be inferred about the intended behavioral question.

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: Self-selection population: participants who accept the invitation to participate and meet study inclusion criteria, participate in a face-to-face interview at the study site, make a self-selection decision, and provide responses to all relevant medical history questions. Purchaser Population: responders who meet study enrollment criteria and purchase/obtain the study medication. Use Phase Norgestrel 0.075 mg: subjects who take at least one dose of study medication during the study.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The clinical trial was terminated before data are collected. No Endpoints calculations were made

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: Males or females at least 12 years of age who presented at a pharmacy study site in response to advertising or who presented to a clinic site seeking an oral contraceptive could be enrolled in the Self-Selection population of the study. Of the 189 subjects who completed the Self-Selection interview, 113 (59.8%) qualified to purchase the product and proceeded to the Use Phase. 109 of 113 purchasers reported taking at least one dose of study product (User Population). The total of subjects is 189.

6. Primary Endpoint

The registry lists the primary outcome as Self-selection, measured over Day One.

The primary endpoint is titled Self-selection. It is described as the proportion of the self-selection population making a correct selection decision regarding use of the product, with a timeframe of Day One. In practical terms, this endpoint is intended to capture whether a person would choose the product appropriately when considering its directions and the conditions that may affect whether it should be used.

Selection is a relevant outcome for a product intended for an OTC-like setting because a consumer must first decide whether the product is suitable before use begins. It is different from adherence or ongoing use: a correct initial choice does not, by itself, show that directions were followed later. The registry lists secondary outcomes that address reported behaviors and label-related circumstances, but these do not substitute for a primary selection estimate.

The record states that the study was terminated before endpoint calculations were made. It therefore reports no calculated proportion for correct selection, and it does not report a denominator or an uncertainty interval for this endpoint. The outcome's definition explains what the study was intended to measure; it is not a result showing how participants selected the product.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical interpretation depends first on distinguishing an outcome definition from an outcome result. A definition identifies what investigators intended to measure; a result requires collected observations to be converted into an estimate, ordinarily with a stated analysis population and denominator. The registry record defines the primary outcome as a proportion of the self-selection population making a correct selection decision on Day One. It also says the trial was terminated before endpoint calculations were made. Thus, the endpoint is described, but no calculated proportion is reported.

What does a proportion represent?

In general, a proportion is a count of participants meeting a specified outcome divided by the number of participants included in the relevant analysis population. The denominator matters because it identifies whose information contributes to the estimate. A proportion without a clear denominator can be difficult to interpret, particularly if some participants did not complete an assessment or were not eligible for it. For this primary endpoint, neither a calculated proportion nor its analysis denominator is reported in the registry record.

A confidence interval, in general, describes the statistical uncertainty around an estimated effect or proportion under a specified model. It is not a guarantee about an individual result, and its width is influenced by the amount and variability of information available. No primary endpoint estimate or confidence interval is reported in the registry record, so the precision of the intended self-selection result cannot be assessed.

Why does the study design matter?

A single-group study can describe outcomes within one group, but it does not provide a concurrent comparison group. Allocation is listed as NA, masking as none, and the model as single-group. There is therefore no randomized contrast to interpret. General causal comparisons require a design and analysis that distinguish the effect of an intervention from other explanations, such as participant characteristics, study procedures, or the setting. No such between-group effect is defined by this record.

The intended setting is OTC-like, and the study objective concerns behavior consistent with package directions. That context helps explain why selection and use are separate outcomes. Selection concerns a decision at the outset; use outcomes concern reported behavior after starting. A finding about one would not automatically establish the other. The record lists secondary outcomes for actual use and label-related circumstances, but the presence of an outcome definition does not show that its data were analyzed.

How should the planning calculations be read?

Planning calculations describe assumptions for a hypothetical future study; they are not results from the observed trial. The stated illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes detecting a stated fraction of an observed effect. For time-to-event illustrations, the stated convention is a total number of events; for other illustrations, the convention is participants per arm. These are planning conventions and not evidence that the trial itself used two arms or enrolled participants according to those assumptions.

The listed trial design is single-group, whereas the planning illustration assumes equal allocation between two arms. The record does not report that this illustration was the trial's original sample-size plan. Sample-size illustrations must not be read as observed power. Observed power is not a substitute for the estimated effect and its uncertainty; when no primary endpoint calculation is reported, the illustration cannot restore that missing result. The registry record does not report a sample-size justification or the protocol's statistical plan.

Why can variation affect analyses?

In general, over-dispersion occurs when observed variability is greater than a statistical model expects. If an analysis assumes less variability than the data contain, its uncertainty estimates can be too small and its apparent precision overstated. Appropriate modeling may need to account for clustering, repeated observations, or other sources of extra variation when those features are present. The registry record does not report an analysis model or enough primary outcome data to assess whether over-dispersion is relevant to the self-selection endpoint.

More broadly, statistical methods need to match the outcome type, design, and analysis population. A binary outcome such as correct versus incorrect selection may be reported as a proportion, while repeated or time-to-event outcomes require different summaries. The registry record does not report the detailed analysis methods used for the listed secondary outcomes. With 0 analyses listed and no endpoint calculations, methods that might ordinarily be applied cannot be evaluated against reported results.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 10 outcome measures, including the primary self-selection outcome and secondary outcomes covering actual use, product-selection precautions, conditions that may arise during use, and pregnancy reports. It lists 0 analyses. No endpoint calculations are reported, so there is no set of reported hypothesis tests from which to assess multiplicity or compare primary and secondary findings.

Multiplicity arises when several outcomes or statistical tests are examined: the chance of at least one apparently unusual result can increase as the number of tests grows. In general, a statistical plan may identify a primary outcome, specify which secondary outcomes are confirmatory or exploratory, and describe any adjustment or other approach to interpretation. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or an analysis plan. It would therefore be inappropriate to assume that any particular adjustment was used.

The record does not describe missing-data amounts, reasons for missingness, imputation, or sensitivity analyses. Since the primary endpoint calculations were not made, there is no reported endpoint denominator or missingness pattern to evaluate. This should not be interpreted as proof that no data were collected for any purpose: safety figures are also listed. Rather, the status of primary outcome data and the handling of incomplete observations are not reported in the registry record.

Analysis populations are only partly characterized by the labels in the record, including self-selection, user, and safety populations. Their detailed eligibility rules and the number contributing to each efficacy outcome are not reported in the registry record. The listed enrollment of 189 and safety population of 116 refer to different record entries; neither can be assumed to be the denominator for the uncalculated primary endpoint.

11. 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 2% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: exposure during pregnancy (0.9%).

The registry record lists a safety population of 116. Within that population, 4 serious adverse events and 28 other adverse events are reported, and deaths are listed as 0. These are counts, not rates. No rate should be inferred without an appropriate denominator and a clearly defined observation period for each event category.

Among the top serious terms, the record lists Exposure During Pregnancy at 0.9%. This term is distinct from the secondary outcome describing the number of pregnancies reported during the study. The record does not provide a pregnancy-outcome calculation or additional details that would establish how the listed serious term relates to that secondary outcome. The percentage should therefore be read as the registry's reported serious-term entry, not as a complete account of pregnancy outcomes.

Safety counts do not answer the primary self-selection question, and they do not establish a comparison with another group. The record does not report further detail on event timing, severity categories beyond the serious and other labels, attribution, or exposure-adjusted rates. Those details are not reported in the registry record, so the listed figures should be interpreted narrowly as the recorded safety counts and term.

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

The record establishes that a Phase 3, single-group study was intended to examine selection and use of norgestrel 0.075 mg under simulated OTC conditions. It also establishes that the study was terminated and that no primary self-selection endpoint calculations were made. These registry entries describe the study's purpose and its reporting limitation; they do not establish whether consumers generally make correct selection decisions.

The absence of a primary estimate is not evidence that the outcome was favorable, unfavorable, or unchanged. It means the registry record does not report a calculated answer to the primary question. Without an estimate, denominator, and uncertainty measure, the magnitude and precision of any self-selection result cannot be assessed. The listed enrollment of 189 does not fill that gap.

The single-group design also sets limits on what the study could establish. It does not offer a randomized comparison with another product or a different setting. Any within-group description, if available, would not by itself show that the product caused a particular behavior or that behavior would be different under another condition. The registry record does not report a comparative effect.

Safety information is present, but its scope is limited to the recorded figures: a safety population of 116, 4 serious events, 28 other events, 0 deaths, and a serious-term entry for Exposure During Pregnancy at 0.9%. These figures do not provide a complete safety evaluation, and they should not be conflated with the uncalculated primary endpoint or the separately listed pregnancy outcome.

The record therefore supports a description of the intended research question, study design, termination status, and limited safety reporting. It does not support a numerical conclusion about correct product selection, the secondary behavioral outcomes, or a treatment comparison. The missing endpoint calculations are central to interpreting the study, rather than a minor qualification to an otherwise reported primary result.

13. Why This Trial Matters Statistically

This study illustrates a useful statistical distinction between whether a trial was designed to ask a relevant question and whether the record contains an analyzable answer. The study's objective was to examine consumer selection and use in an OTC-like environment, and its primary endpoint was framed as a proportion making a correct selection decision. That is a clearly interpretable type of question, but the registry record states that no primary endpoint calculations were made.

The case also highlights why design labels matter. A single-group study can be useful for describing behavior in a particular setting, but it does not create a randomized control contrast. Allocation is recorded as NA and masking as none, so the study should not be read as a comparison of treatment groups. Statistical interpretation must follow the design actually described, not a comparison that the record does not contain.

Another important lesson is that enrollment and analysis populations are not interchangeable. The record lists enrollment as 189 and a safety population of 116, but it does not report a denominator for the primary self-selection outcome. A count associated with enrollment cannot be substituted for an endpoint analysis population when no calculation was made.

Finally, planning illustrations are not study results. Assumptions such as two-sided significance level 0.05, equal allocation between two arms, and a normal approximation can describe hypothetical planning calculations. They do not establish that this single-group study used those methods, nor do they indicate observed power. Keeping design, planning, analysis, and results separate is essential when assessing what the registry record can and cannot support.

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 direct limitation is that the trial was terminated before primary endpoint calculations were made. As a result, the record does not report the primary self-selection estimate, its denominator, or its precision. The same record lists 0 analyses, so the listed outcome definitions cannot be treated as completed results.

The study is described as single-group, with allocation recorded as NA and masking as none. There is no comparator arm, which prevents a like-for-like comparison and limits causal interpretation. The intended OTC-like environment is relevant to the study objective, but the registry record does not provide enough detail to assess how closely the study setting represented ordinary consumer behavior.

The record lists enrollment as 189 but does not describe how many people entered each outcome population or contributed to each behavioral assessment. The safety population is listed separately as 116. Detailed population definitions, attrition, missingness, and handling of incomplete outcomes are not reported in the registry record. The termination entry makes these omissions especially important for interpreting the absent primary calculation.

Further limitations include the lack of a reported statistical analysis plan, sample-size justification, multiplicity approach, and detailed methods for the secondary outcomes. The planning illustration assumptions do not establish the study's own design or analysis plan. Safety reporting is also limited: event counts and a serious-term percentage are listed, but further detail on timing, attribution, and event-specific denominators is not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study of Oral Contraception Under Simulated OTC Conditions — NCT03559010.
• Registry record last updated 2022-04-04; status last verified 2022-03.
• Results first posted 2022-04-04.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes NCT03559010, titled A Study of Oral Contraception Under Simulated OTC Conditions, with the official title referring to the OPTION trial. It is listed as Phase 3, single-group, with no masking and allocation recorded as NA. The study evaluated norgestrel 0.075 mg tablets in an OTC-like setting, with a stated regimen of one tablet daily at the same time for up to 16 weeks.

The record lists enrollment as 189, a start date of 2018-04-27, a primary completion date of 2018-09-09, and status as terminated. The primary outcome was correct self-selection on Day One. The record states that no self-selection endpoint calculations were made and lists 0 analyses.

Safety information includes a safety population of 116, 4 serious events, 28 other events, 0 deaths, and Exposure During Pregnancy at 0.9% among the top serious terms. The registry record does not report a primary endpoint estimate, detailed statistical plan, or sample-size justification.