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 A Study of Breastfeeding in Buprenorphine Maintained Women (NCT01806389), a registered phase not stated study. The primary outcome is Maternal Plasma Concentrations of Buprenorphine.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01806389 |
| Phase | Phase not stated |
| Condition | Opioid Dependency |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Johns Hopkins University |
| Results posted | Yes |
2. Clinical Question
Population
Women maintained on buprenorphine who wished to breastfeed, together with their neonates. The registry record lists opioid dependency as the condition and describes a pilot study focused on lactation among buprenorphine-maintained women.
Intervention
Buprenorphine maintenance in the postpartum period. The study description concerns women maintained on buprenorphine at delivery; it does not describe assigning a new treatment.
Comparator
No comparator group is described. The registry lists a buprenorphine group, and the allocation method is not stated. This is not a like-for-like controlled comparison.
Primary question
What maternal plasma buprenorphine concentrations are observed at the specified postpartum sampling times? The study’s broader stated goal was to generate pilot data relevant to breastfeeding and buprenorphine maintenance, including information intended to inform safety considerations.
The primary outcome is a description of maternal concentrations, not a direct comparison of breastfeeding with another feeding approach or of buprenorphine with another medication. Plasma samples were to be obtained at the time of peak buprenorphine levels on Days 2,3,4,14 and 30 after delivery. The registry specifies a median and full range for this outcome. Those summaries could describe the distribution of measured concentrations, but the registry record does not give the values themselves.
The clinical motivation in the registry is the limited information it describes about buprenorphine maintenance and lactation, alongside the potential relevance of breastfeeding for prenatally opioid-exposed neonates. The stated goals include developing information for practitioners and informing the FDA. These are aims, not findings. The registry record does not establish that the study answered a clinical safety question or supports a treatment recommendation.
3. Trial Design
The registry identifies NCT01806389 as a completed pilot study titled “A Study of Breastfeeding in Buprenorphine Maintained Women.” Its official title is “Lactation Among Buprenorphine Maintained Women: A Pilot Study.” Johns Hopkins University is listed as the sponsor. The recorded enrollment is 10, and the condition is opioid dependency. The start is recorded as 2013-02 and primary completion as 2016-02.
The study description focuses on breastfeeding women maintained on buprenorphine and their neonates. It states that five pregnant buprenorphine-maintained breastfeeding women and their neonates would be enrolled. The record also gives total enrollment as 10. These are distinct entries in the registry; the reason for the difference is not reported in the registry record. The description is incomplete, ending before it fully explains the enrollment process.
Only a buprenorphine group is listed. The allocation method is not stated, and the registry characterizes the arms as not forming a like-for-like control comparison. Thus, the design information does not support interpreting the study as a randomized comparative trial. The registry lists three outcome measures, but detailed descriptions are available only for the primary outcome: maternal plasma concentrations of buprenorphine, summarized by median and full range at specified postpartum times.
The registry marks the study completed, but completion does not by itself establish that all planned measurements were obtained or analyzed. The registry records zero analyses. Detailed methods for recruitment, follow-up, sample handling, data quality, and statistical analysis are not reported in the registry record. Nor is a sample-size justification reported in the registry record. The stated pilot aim is consistent with a study intended to generate initial information, but the record does not describe a formal inferential comparison or a protocol for evaluating a treatment effect.
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: Fourteen women were consented for this protocol but 4 were withdrawn for various reasons, i.e. inability to provide samples, changed mind about breastfeeding.
Overall Study
| Stage | Buprenorphine Maintained Lactating Women |
|---|---|
| STARTED | 14 |
| COMPLETED | 10 |
| NOT COMPLETED | 4 |
Reasons for not completing this period:
| Reason | Buprenorphine Maintained Lactating Women |
|---|---|
| Withdrawal by Subject | 4 |
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 | Buprenorphine Maintained Lactating Women |
|---|---|---|
| Participants analysed | 10 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 10 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 26.1 (SD 4.7) |
| Sex: Female, Male: Female | Participants | 10 |
| Sex: Female, Male: Male | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 |
| Race (NIH/OMB): White | Participants | 9 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Maternal Plasma Concentrations of Buprenorphine, measured over Days 2,3,4,14 and 30 after delivery.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | ug/mL |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is maternal plasma concentration of buprenorphine, expressed in ug/mL. The registry specifies that plasma is obtained at the time of peak buprenorphine levels on Days 2,3,4,14 and 30 after delivery. It identifies the median and full range as the summary measures.
A concentration measurement describes the amount of a substance in the sampled plasma at a particular time. Repeated sampling at specified times can characterize how measured concentrations vary across postpartum observations. A median gives a central value that is less affected by unusually high or low observations than a mean can be. A full range describes the lowest and highest observed values, but it does not show how observations are distributed between those endpoints or how precisely the median is estimated.
In general, these summaries can be useful in a pilot study whose aim is to characterize measurements and inform future research. They do not, on their own, establish how much buprenorphine reaches breast milk or an infant, nor do they directly measure infant outcomes. The registry identifies maternal plasma concentration as the primary endpoint; it does not report the numerical concentrations, the number of samples available at each time, or the detailed results for the other outcome measures. The endpoint therefore indicates what the study set out to measure, while the record does not provide the numerical findings needed to assess the observed concentration pattern.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a pilot investigation of maternal plasma buprenorphine concentrations among breastfeeding women maintained on buprenorphine. The primary outcome is specified as a median and full range at postpartum sampling times. However, numerical results for that outcome are not reported in the registry record. Consequently, the record does not allow a reader to determine the observed concentration values, their variability, or whether measurements differed across the listed times.
The study’s broader purpose was to generate pilot data relevant to the safety of breastfeeding while on buprenorphine maintenance and to develop information for practitioners. These statements describe motivation and intended use, not evidence of a demonstrated safety profile. The primary endpoint is maternal plasma concentration; no numerical infant outcome findings are included in the available record. Therefore, the primary endpoint cannot by itself answer whether breastfeeding is safe for an infant, and the absence of reported concentrations prevents even a descriptive assessment of the maternal measurements.
The record lists a total enrollment of 10, while the study description says five women and their neonates would be enrolled. The difference is not explained in the registry record. It also lists one buprenorphine group, with allocation not stated, and notes that the arms are not a like-for-like control comparison. A between-group treatment effect cannot be inferred from this design information. The record lists zero analyses, which means no analyses are represented in the registry entry; it does not establish what work may or may not have occurred outside that entry.
In general, estimates from a small pilot study can be imprecise, especially when outcomes are measured at multiple times or when only some participants contribute measurements at each time. A median and range describe the observed sample, not necessarily the broader population. Confidence intervals, if reported, would help convey uncertainty around an estimate; none are reported for the primary outcome. Without outcome values, uncertainty estimates, or a detailed analysis plan, the statistical precision of any concentration estimate cannot be evaluated.
The registry’s sample-size assumptions describe a separate planning illustration: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. Those assumptions do not describe the listed single-group study and should not be read as the trial’s design or as observed power. No sample-size justification is reported in the registry record. In sum, the record establishes the study question and outcome framework, but it does not report numerical primary results that support a conclusion about concentrations or infant safety.
9. Statistical Methods Explained
The statistical information in the registry is limited. It names a primary outcome, its units, summary measures, and sampling times, but the registry record does not report the numerical outcome values or a detailed analysis plan. The explanations below describe general statistical concepts, not methods confirmed to have been used in this study.
What does a median describe?
In general, the median is the central observation after measured values are ordered. It is often useful when a distribution is skewed or contains extreme observations because it is less influenced by those values than the mean. The median does not show the full shape of the distribution. Two groups of measurements can have the same median but differ in spread, clustering, or the presence of extreme values. The registry specifies a median for maternal plasma concentrations, but it does not report the median itself.
What does a full range add?
In general, a full range reports the smallest and largest observed values. It gives a simple indication of the span of the data, but it is sensitive to extreme observations and does not describe how many measurements lie near either endpoint. It also does not quantify the precision of the median. Measures such as a confidence interval address uncertainty in an estimate; the registry record does not report confidence intervals for the primary outcome. Without the sample values and the number of observations contributing to each summary, neither the spread nor precision of the reported measure can be assessed.
Why specify sampling times?
The primary outcome description specifies maternal plasma sampling at the time of peak buprenorphine levels on Days 2,3,4,14 and 30 after delivery. In general, measurements at repeated times can describe how an outcome varies over follow-up. This raises analytical questions: whether each time is summarized separately, whether within-person changes are estimated, and how incomplete follow-up is handled. The registry record gives the timing and intended summary measure, but it does not state whether a longitudinal model or any other repeated-measures method was used. It also does not report how many observations were available at each time.
Repeated measurements from one participant are usually related rather than independent. In general, an analysis that treats correlated measurements as independent can misstate uncertainty. Methods for repeated data account for that dependence, but the appropriate approach depends on the design, distribution, and missingness pattern. The registry record does not describe the analysis used, so no particular model should be attributed to the investigators.
What is the role of a comparator?
The registry lists a buprenorphine group and says the arms are not a like-for-like control comparison. Allocation is not stated. In general, a comparator can help distinguish changes associated with an intervention from changes that might occur for other reasons. Without a described comparator, the listed design is primarily suited to describing observations in the enrolled group, rather than estimating a comparative treatment effect. The record does not report a randomized allocation or a controlled contrast.
How should the planning assumptions be understood?
The registry includes planning assumptions for an illustration: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. It distinguishes participants per arm from total events for time-to-event calculations. These assumptions concern a planning illustration, not a documented design for the listed study. The study entry lists one group and does not report a comparative analysis. Planning sample sizes are hypothetical quantities under specified assumptions; they are not observed participants and are not observed power. No numerical planning result is described in the registry record.
In general, significance levels and power assumptions concern the operating characteristics of a planned hypothesis test. They do not establish that an observed effect is important, precise, or causal. A design and analysis need to align: an equal-allocation two-arm calculation does not directly describe a single-group concentration study. The registry record does not report the original sample-size justification, the effect used for the trial’s design, or a formal hypothesis-testing plan.
What does the lack of reported analyses imply?
The registry lists zero analyses. This indicates that the entry does not include registered analysis results; it should not be expanded into a claim about whether investigators performed work outside the registry. The record also does not identify the statistical software, adjustment variables, handling of outliers, or rules for measurements below assay limits. Those details are not reported in the registry record. Without them and without numerical results, the statistical methods and findings cannot be independently appraised from the registry entry.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists three outcome measures and gives the primary outcome sampling times as Days 2,3,4,14 and 30 after delivery. Multiple outcomes or repeated time points can create multiplicity questions if several statistical tests are performed. In general, testing many hypotheses can increase the chance of obtaining at least one apparently notable result by chance. Researchers may address this through a prespecified hierarchy, adjustment, or a clearly descriptive analysis plan. The registry record does not report whether tests were planned at each time, whether multiplicity adjustments were used, or how the other outcome measures were handled.
The record identifies the primary outcome, but does not provide a full statistical analysis plan or numerical results. It does not report whether the time-specific summaries were intended as separate endpoints or as components of a repeated-measures analysis. No p-values or confidence intervals for the primary outcome are reported in the registry record, and the record lists zero analyses. It is therefore not possible to assess whether any inferential testing was conducted or how it was interpreted.
Missing-data methods are also not described. The registry record does not report whether measurements were missing, why they might have been missing, how many participants contributed at each time, or whether any imputation or other handling strategy was used. In general, missingness can affect estimates when the availability of a measurement is related to the value being measured or to participant characteristics. The direction and magnitude of any such effect cannot be determined without details about the missingness and analysis.
Analysis populations, including any distinction between enrolled participants and participants with usable samples, are not reported in the registry record. The difference between the listed enrollment of 10 and the description of five planned women is not explained. This prevents a clear account of which participants or samples contributed to the primary endpoint.
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 |
|---|---|---|---|
| Buprenorphine | 0 | 14 | 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 |
|---|---|
| Buprenorphine | 0 of 14 |
The registry records zero serious adverse events among 14 participants at risk and zero other adverse events among 14 participants at risk in the buprenorphine group. These figures are counts recorded in the registry; they do not mean that the risk is known to be absent. A zero count in a finite group can occur even when an event is possible, and the record does not provide an uncertainty interval for these counts.
The adverse-event denominator is recorded as 14, while total enrollment is recorded as 10. The reason for this difference is not reported in the registry record, so the denominator should not be reconciled by assumption. The record does not list any serious adverse-event terms. Deaths are not reported in the registry record. No event-specific timing, severity detail beyond the serious/other categories, relationship assessment, or follow-up completeness is described.
These registry figures should be read as a limited safety snapshot, not as proof that no adverse events occurred in any broader population or that breastfeeding during buprenorphine maintenance has been established as safe. The primary outcome concerns maternal plasma concentrations; the adverse-event counts do not substitute for numerical infant outcome results, which are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The study addresses an important information gap identified in its own description: it seeks pilot data about lactation among women maintained on buprenorphine. The registry specifies maternal plasma buprenorphine concentrations as the primary outcome and identifies postpartum sampling times. It also describes broader aims related to informing safety considerations and practitioner guidance. These aims establish the motivation for the research, not conclusions from it.
The posted registry record does not include numerical results for the primary outcome. It therefore cannot show the actual concentration values, the degree of variation among women, or the pattern across sampling times. The record also does not provide numerical findings for the other outcome measures. Without those data, a reader cannot judge the estimates’ magnitude or precision.
The record lists one buprenorphine group and no like-for-like control comparison. Accordingly, the information does not provide a controlled estimate of how outcomes differ under alternative treatments or feeding practices. Even if concentration summaries were available, maternal plasma concentration would not alone answer every question about transfer into breast milk, infant exposure, or infant outcomes. The available registry entries do not give numerical results for those questions.
The recorded zero counts for serious and other adverse events are limited to the registry’s stated denominator of 14 participants at risk. They should not be treated as proof of zero risk. The unexplained difference between that denominator and the enrollment of 10 further limits interpretation of the safety counts.
Overall, the record documents a completed pilot study with a defined primary measurement and stated research aims, but its missing numerical results and sparse analysis details prevent a statistical conclusion about the measured concentrations or a broader safety conclusion. The findings do not establish that breastfeeding during buprenorphine maintenance is safe or unsafe, and they do not support treatment advice. They show what the study set out to investigate and what information the registry record does not report.
13. Why This Trial Matters Statistically
This trial matters statistically because its question is exploratory and its primary outcome is a biological measurement collected at specified postpartum times. Pilot studies can help describe whether measurements are obtainable, how variable they may be, and what questions merit more formal investigation. Those uses are different from demonstrating a treatment effect or establishing safety. The registry identifies a pilot aim, but does not report the concentration results needed to evaluate what was learned from this study.
The design details also matter. A single listed group without a described comparator supports a descriptive interpretation more readily than a causal comparison. A reader should not interpret the registry’s planning assumptions for equal allocation between two arms as though they describe the actual study. In general, sample-size illustrations depend on assumptions about the design and target effect; if those assumptions do not match the observed study, the resulting quantities are not evidence about its power or findings.
Repeated sampling creates a further statistical consideration. In general, observations from the same person can be correlated, and both the number of available measurements and their timing affect how precisely a pattern can be described. The registry gives intended time points but no sample counts by time, numerical summaries, or analysis approach.
Finally, reporting is part of statistical interpretation. The registry’s stated aims and endpoint are informative, but zero registered analyses and absent numerical outcome values leave the central empirical question unanswered in the record. The enrollment and adverse-event denominator also differ without explanation. Recognizing these limits helps distinguish a research question and study framework from evidence that can support an estimate or a safety conclusion.
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 for statistical interpretation is that the registry record does not report numerical values for the primary endpoint. It specifies maternal plasma concentrations, a median and full range, and sampling times, but does not give the resulting summaries or the number of observations contributing to them. The record also does not provide numerical results for the other outcome measures.
The registry lists total enrollment as 10, while the study description states that five women and their neonates would be enrolled. It does not explain the discrepancy or identify how many participants contributed data. The adverse-event record uses 14 participants at risk, a different denominator whose relationship to enrollment is not reported in the registry record.
Only a buprenorphine group is listed, and allocation is not stated. The registry explicitly notes that the arms do not form a like-for-like control comparison. This constrains interpretation to description rather than a controlled comparison. The registry does not report detailed recruitment criteria, follow-up completeness, missing-data handling, assay details, or a statistical analysis plan. The description of the study methods is also incomplete.
Although the record states that the study was completed, completion status does not supply missing outcome data. It lists zero analyses, and the reason analyses are absent is not reported in the registry record. The sample-size assumptions describe a planning illustration based on a two-arm framework, not a stated justification for this listed design. These limitations mean that the record can establish the intended measurement and context, but cannot support an assessment of the primary estimates’ precision or a broad safety conclusion.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of Breastfeeding in Buprenorphine Maintained Women — NCT01806389.
- Registry record last updated 2017-06-15; status last verified 2017-02.
- Results first posted 2017-03-22.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT01806389 is a completed pilot study sponsored by Johns Hopkins University, titled “A Study of Breastfeeding in Buprenorphine Maintained Women.” Its official title is “Lactation Among Buprenorphine Maintained Women: A Pilot Study.” The recorded condition is opioid dependency, enrollment is 10, and the listed group is buprenorphine. The start is recorded as 2013-02 and primary completion as 2016-02.
The primary outcome is maternal plasma buprenorphine concentration in ug/mL, summarized by median and full range at the time of peak levels on Days 2,3,4,14 and 30 after delivery. The record lists three outcome measures and zero analyses. Numerical primary-outcome results are not reported in the registry record. Serious and other adverse-event counts are each recorded as zero among 14 at risk; the relationship between that denominator and enrollment is not explained. The record does not describe a like-for-like control comparison or state an allocation method.