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 Low Plasma Mannose Binding Lectin (p-MBL) Level is a Risk Factor for Recurrent Pregnancy Loss (RPL) (NCT04017754), a registered phase not stated study. The primary outcome is Plasma MBL Level (ug/ml).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04017754 |
| Phase | Phase not stated |
| Condition | Recurrent Miscarriage, Spontaneous Abortion, Mannose-Binding Lectin Deficiency |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 452 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Aalborg University Hospital |
| Results posted | Yes |
2. Clinical Question
Population
The study sample comprised women with unexplained recurrent pregnancy loss. The record says inclusion required a history of 3 or more consecutive spontaneous pregnancy losses and that biochemical and clinical losses documented in hospital records were accepted. The description of further eligibility criteria is incomplete in the registry record. Separately, the primary-outcome population is described as 18 women who were pregnant <12 weeks when the blood sample was collected.
Intervention
There is no treatment intervention described. The study measured plasma mannose-binding lectin (p-MBL) in a blood sample. The stated aim was to examine whether p-MBL could be a biomarker associated with recurrent pregnancy loss and, secondarily, whether it might be associated with reproductive and perinatal outcomes.
Comparator
The reference group comprised Danish female blood donors of reproductive age, with a stated age range of 21 to 45 years. The record says no other information was available about these donors. This is not a randomized comparison, and the registry record flags the groups as not being a like-for-like control comparison.
Primary question
The primary measure was plasma MBL level, described as a median with an inter-quartile range and collected at first consultation. The clinical question is whether the recorded p-MBL level is associated with recurrent pregnancy loss, with the broader stated aim of considering p-MBL as a possible risk marker. The primary result itself is not reported in the registry record, so the direction, size, and precision of any group difference cannot be assessed from this record.
3. Trial Design
This completed study is registered as an observational comparison rather than a randomized treatment trial. The registry record lists an enrollment of 452 and describes a study sample of women with unexplained recurrent pregnancy loss alongside a reference group of Danish female blood donors. The study sample description states that women had a history of 3 or more consecutive spontaneous pregnancy losses, with biochemical and clinical losses documented in hospital records accepted. The eligibility description is truncated, so additional inclusion or exclusion criteria are not fully reported in the registry record.
The reference group is described as reproductive-age Danish female blood donors aged 21 to 45 years. The record says no other information was available about them. It explicitly cautions that the arms are not a like-for-like control comparison, and allocation is not stated. As a result, the contrast is observational: the groups were not assigned by randomization, and the record does not establish that they were comparable on characteristics that could affect p-MBL levels.
The sponsor is Aalborg University Hospital. The study start is listed as 2016-01-01, primary completion as 2021-03-29, and status as completed. These administrative details describe the registered study timeline, not the timing or completeness of every individual measurement.
The primary measurement was p-MBL in a blood sample at first consultation, with results stated to be accessible within 3 weeks. A separate population note says 18 women were pregnant <12 weeks at blood collection. The registry record does not explain how this subset relates to the full study sample or reference group, nor does it report the analysis population used for the primary comparison. The title field names Plasma MBL Level (ug/ml), while the unit field says ug/l; this discrepancy in the listed units is not resolved in the registry record.
The record lists secondary outcomes involving birth weight, very low birth weight, preeclampsia, and emergency caesarean section, comparing pregnancy outcomes before or after recurrent pregnancy loss. It does not provide those outcome results or define the corresponding analysis methods in the 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.
Before assignment: The study sample consisted of 267 female patients with RPL fulfilling the inclusion criterias.
Overall Study
| Stage | Study Sample | Control Group 1 |
|---|---|---|
| STARTED | 267 | 185 |
| COMPLETED | 267 | 185 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: 18 women were pregnant \<12 weeks when blood sample was collected.
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 | Study Sample |
|---|---|---|
| Participants analysed | 267 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 267 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 33.2 (SD 5.3) |
| Sex: Female, Male: Female | Participants | 267 |
| Sex: Female, Male: Male | Participants | 0 |
| Race/Ethnicity, Customized: Caucasian | participants | 267 |
| Race/Ethnicity, Customized: Unknown | participants | 0 |
| Region of Enrollment: Denmark | participants | 267 |
| Body mass index | kg/m² | 25.4 (16.8 to 50.0) |
| Number of consecutive pregnancy losses | consecutive pregnancy losses | 3 (3 to 13) |
| Percentage with primary Recurrent pregnancy loss (RPL) | Percentage of all RPL patients | 53.9 |
6. Primary Endpoint
The registry lists the primary outcome as Plasma MBL Level (ug/ml), measured over At first consultation. Results accessible within 3 weeks..
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | ug/l |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is plasma mannose-binding lectin level, measured from a blood sample. The endpoint description calls it a mannose-binding lectin level in a blood sample and specifies measurement at first consultation, with results accessible within 3 weeks. The registry record says the summary measure is the median and the measure of dispersion is the inter-quartile range. It also notes that 18 women were pregnant <12 weeks when blood was collected.
MBL is the biomarker under study; the stated research question is whether plasma MBL levels are associated with recurrent pregnancy loss. A biomarker endpoint can describe a biological measurement and allow a comparison between groups, but an association alone does not establish that the marker causes the clinical outcome or can predict it accurately for individuals. Those further claims require appropriate evidence and a clear analysis.
The median describes the central position of observed measurements, while the inter-quartile range describes the spread of the middle portion of those measurements. These summaries can be useful when data are skewed or contain unusually high or low values. As a general statistical point, they do not by themselves quantify uncertainty about a difference between groups; that requires a comparison estimate and an uncertainty measure, such as a confidence interval.
The registry record does not report the median, inter-quartile range, group contrast, confidence interval, or p-value for the primary endpoint. It also lists the endpoint title unit as ug/ml and the unit field as ug/l, without resolving the difference. Consequently, neither the magnitude nor precision of the primary result can be interpreted from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central limitation for interpreting this study record is that it identifies the primary measure but does not report its observed value or a comparison between the study sample and reference group. The registry record therefore does not show whether the groups had similar or different p-MBL levels, how large any difference was, or how precisely it was estimated. A conclusion about an association cannot be drawn from the endpoint description alone.
The study question is observational. Women with recurrent pregnancy loss and blood donors were not assigned to groups by randomization, and the record flags the groups as not being like-for-like. This matters because a difference in a biomarker between groups could reflect differences in other characteristics, selection into the groups, or measurement circumstances, rather than an effect connected specifically to recurrent pregnancy loss. The registry record does not report enough information to assess the extent of such potential confounding.
The description of the reference group says that the donors were Danish women of reproductive age, aged 21 to 45 years, and that no other information was available about them. The record does not provide comparable characteristics for the study sample or explain whether any adjustment was made. It also does not report the primary analysis method, any adjusted estimates, or the sample size used in the reported primary analysis. The enrollment figure alone cannot establish which participants contributed to each endpoint.
The primary endpoint is described using a median and inter-quartile range. These summaries can communicate the location and spread of measurements, but a group-level median is not a measure of individual prediction. Even if an association were reported, further evidence would be needed to evaluate how well p-MBL distinguishes people with different outcomes, whether the association persists after accounting for other factors, and whether it is useful as a biomarker in the intended setting.
The registry lists secondary outcomes related to birth weight, very low birth weight, preeclampsia, and emergency caesarean section in pregnancies before or after recurrent pregnancy loss. No results for those outcomes are reported in the registry record. The brief study description states that these outcomes were of secondary interest, but it does not provide estimates, uncertainty intervals, or a statistical interpretation.
The record lists 24 outcome measures and one analysis, but the relationship between these entries and the individual outcome results is not explained. It does not report a multiplicity strategy, missing-data handling, or analysis populations. These omissions make it difficult to assess how the analysis was selected and whether the reported findings, if available elsewhere, would account for multiple comparisons or incomplete observations.
Overall, the record documents a completed observational study with a biologically measured primary endpoint and stated clinical aims. It does not include the result needed to evaluate the primary question. The title’s wording presents low p-MBL as a risk factor, but the registry record does not provide numerical outcome evidence that can be used to verify the size, precision, or robustness of that claim.
9. Statistical Methods Explained
What does a median and inter-quartile range describe?
The primary endpoint is summarized as a median with an inter-quartile range. The median is the middle value when measurements are ordered. The inter-quartile range describes the interval spanning the central half of the measurements. As a general statistical explanation, these summaries are often useful for measurements that are skewed or contain extreme observations, because they are less affected by extremes than a mean and standard deviation.
These descriptive summaries do not, on their own, answer whether two groups differ beyond what might be expected from sampling variation. A group comparison needs an estimate of the contrast and ideally an uncertainty interval. A confidence interval expresses a range of values compatible with the data under the statistical model; it reflects precision, not the probability that a particular hypothesis is true. The registry record does not report a confidence interval or the primary group comparison.
What does an observational comparison allow?
The record describes a study sample and a reference group, without a randomized allocation. As a general principle, randomization can help balance both measured and unmeasured prognostic factors between treatment groups. It is not part of the comparison. In an observational comparison, group differences may be associated with the outcome of interest, but other differences between groups can also contribute.
The record specifically notes that the groups are not a like-for-like control comparison. It gives limited information about the reference donors and does not report an adjusted analysis or the characteristics compared across groups. Therefore, readers cannot determine from this record whether possible confounding was addressed. Adjustment can account for measured variables included in a model, but it cannot automatically remove bias from unmeasured or poorly measured factors.
Why does the endpoint summary matter?
A biomarker level is a measurement, not itself a clinical outcome. A comparison of p-MBL levels could address whether the marker differs across the defined groups. To establish whether it predicts recurrent pregnancy loss or other outcomes, analysis would need to relate the marker to those outcomes and assess predictive performance. To support a causal interpretation would require additional design and analytic considerations. These are general distinctions between association, prediction, and causation; the registry record does not report analyses that resolve them.
The endpoint is recorded as a median and inter-quartile range, but the actual values are not reported in the registry record. The endpoint title and unit fields also differ: the title uses ug/ml and the unit field uses ug/l. A unit difference can affect the interpretation of the scale, so the unresolved discrepancy prevents a confident reading of any level even if a value were presented without clarification.
What can the planning assumptions tell readers?
The record describes a planning illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is expressed as a stated fraction of the observed effect, and that the calculations are planning illustrations rather than the study’s own design. These details describe assumptions for illustrative sample-size calculations; they do not establish the study’s original sample-size justification or the statistical plan actually used.
As a general explanation, a sample-size calculation estimates how many observations may be needed to detect a specified effect under stated assumptions. It depends on factors such as the target effect, variability, allocation, statistical test, and chosen error rates. If an assumed effect is smaller, more observations are generally needed to detect it with the same planned power. Such calculations are prospective planning tools. They are not observed power and cannot substitute for the observed effect estimate or its confidence interval.
The registry record does not report the trial’s original sample-size justification, or establish that the planning illustration governed recruitment or analysis. The enrollment figure does not show how many participants contributed to the primary endpoint. Nor does the record give the calculated participant requirements for the illustrations, so no numerical planning result can be interpreted from the record.
What is not reported about the analysis?
The record lists 24 outcome measures and one analysis, but does not explain which statistical test or model was used for the primary endpoint. It does not report whether estimates were adjusted, how missing measurements were handled, whether any observations were excluded from analysis, or which population was included in each result. These details can affect the meaning of an estimate and its uncertainty.
As a general point, an analysis plan specifies outcomes, comparisons, models, and data-handling rules before results are examined. Prespecification can reduce the risk that analytic choices are influenced by observed results. The registry record does not report whether such a plan was prespecified, whether interim analyses occurred, or how multiplicity was handled. None of those practices should be inferred from the fact that the study is marked completed.
Because the primary numerical result and its analytic details are absent, the available record supports a description of the research question and design but not a quantitative evaluation of the primary finding. Interpretation would require the group-level endpoint data, the comparison estimate, its uncertainty, and enough methodological detail to understand the analysis population and any adjustments.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 24 outcome measures and one analysis. It does not describe how those outcomes were organized into primary and secondary statistical tests, whether all were analyzed, or whether any adjustment for multiple comparisons was used. No multiplicity procedure is reported in the registry record.
As a general statistical principle, when many hypotheses are tested, the chance of at least one apparently unusual result can increase if each test is interpreted without considering the full set. Methods for handling multiplicity depend on the aims and structure of the analyses. The record does not identify a method or explain whether the listed outcome measures were treated as separate tests. The number of outcomes alone does not establish that a particular adjustment was required or used.
Missing-data handling is also not reported in the registry record. It does not state how many primary measurements were unavailable, why data might be missing, whether incomplete records were excluded, or whether any imputation method was used. Without this information, readers cannot assess whether the analyzed participants might differ systematically from those without usable measurements.
The analysis populations are not described beyond the note that 18 women were pregnant <12 weeks when the blood sample was collected. The record does not explain how that population relates to the study sample or reference group, or which participants contributed to each outcome analysis. It does not report exclusions or an analysis set definition. These omissions limit assessment of selection into the analyzed data and the generalizability of any estimate.
The statistical plan, interim analyses, and sample-size justification are not reported in the registry record. The planning assumptions described elsewhere in the record are explicitly illustrative and do not fill those gaps.
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 |
|---|---|---|---|
| Study Sample | 0 | 267 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Study Sample | 0 of 267 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Study Sample | 0 of 267 |
The serious adverse event information lists the study sample as the group at risk, with 267 at risk and 0 serious events affected; the other adverse-event count is also 0, and deaths are listed as 0. The record lists no top serious-event terms. These are the registry’s reported counts for this entry.
Those figures should be read narrowly. They do not provide a detailed account of how adverse events were defined, collected, monitored, or attributed. The registry record does not describe the safety surveillance procedures, the reporting period for these figures, or whether the adverse-event fields cover every event of clinical interest. A count of 0 in the reported fields is not proof that no adverse events of any kind occurred.
This is an observational study of a biomarker, not a randomized treatment comparison as described in the record. The safety fields therefore do not provide a comparative estimate of treatment-related harm. The record also does not list serious-event terms, so there are no event categories to interpret. These safety entries should not be used to infer broader safety conclusions beyond the specific recorded counts.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the study was designed to examine plasma MBL levels in relation to recurrent pregnancy loss, with additional interest in reproductive and perinatal outcomes. It identifies a study sample with unexplained recurrent pregnancy loss, a reference group of Danish female blood donors, and a primary endpoint summarized as a median with an inter-quartile range. The study is marked completed.
What the record does not establish is the observed primary result. It provides no group medians, inter-quartile ranges, comparison estimate, confidence interval, or p-value. Consequently, it is not possible to determine from the registry record whether p-MBL levels differed between the groups, how large any difference was, or how precise an estimate might be. The registry’s title uses risk-factor language, but the numerical evidence needed to evaluate that characterization is not reported.
Even a documented difference between the groups would not by itself demonstrate that p-MBL causes recurrent pregnancy loss. This is an observational comparison, allocation is not stated, and the record warns that the groups are not like-for-like. Other differences between the women with recurrent pregnancy loss and the blood donors could influence the comparison. The record does not explain whether adjustment was undertaken.
A group-level biomarker result also does not establish that p-MBL can accurately predict an individual’s outcome. Prediction requires evidence about how well a marker classifies or forecasts outcomes, including its performance in an appropriate population. The record does not report such analyses. Likewise, it does not report results for the listed secondary outcomes concerning birth weight, very low birth weight, preeclampsia, or emergency caesarean section.
The appropriate reading is therefore limited: the registry record documents the research question, study groups, endpoint description, and some administrative details, but does not provide outcome data sufficient to judge the primary association or the secondary outcomes. It cannot support conclusions about causation, individual prediction, or clinical usefulness.
13. Why This Trial Matters Statistically
This study raises a statistical question that often arises in biomarker research: whether a measured biological characteristic is associated with a clinical history or outcome. Answering that question requires more than identifying a plausible marker and collecting measurements. Readers need the endpoint values, a clearly defined comparison, and an estimate of uncertainty to judge the size and precision of the observed association.
The record is also a useful reminder that a reference group is not automatically a valid control group. Here, the registry explicitly says the study arms are not a like-for-like comparison. The reference group consists of Danish female blood donors of reproductive age, and the record says no other information was available about them. That limitation matters statistically because differences in group composition can complicate interpretation of an observed biomarker contrast.
Another important distinction is between association and prediction. A difference in p-MBL levels, if demonstrated, would not by itself show how well the marker forecasts an outcome for an individual. Prediction requires a different set of evaluations from a simple group comparison. The record’s stated aim includes considering p-MBL as a biomarker, but it does not report predictive-performance results.
The primary endpoint is summarized by a median and inter-quartile range, a reasonable descriptive approach for data that may not follow a symmetric distribution. Yet the actual summaries and comparison are absent from the registry record. The discrepancy between the endpoint title’s unit and the listed unit further illustrates why measurement definitions need to be clear for interpretation and replication.
Finally, the registry lists multiple outcomes but does not report multiplicity handling, missing-data methods, or the analysis populations. Those details are part of assessing how robustly the data answer the research question. The record therefore illustrates why transparent results and methods are essential alongside a completed-study status and a stated scientific rationale.
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 principal limitation is that the primary endpoint results are not reported in the registry record. The median, inter-quartile range, group contrast, confidence interval, and p-value are absent, preventing quantitative interpretation of the primary question. The registry title’s claim that low p-MBL is a risk factor cannot be independently evaluated from the available record.
The comparison is observational and the registry explicitly flags the study arms as not being a like-for-like control comparison. The reference group is described as Danish female blood donors aged 21 to 45 years, with no other information available about them. The record does not report participant characteristics that would allow readers to assess comparability or understand whether potential confounding was addressed.
The study sample eligibility description is incomplete, ending mid-description, and the primary-endpoint population note identifies 18 women who were pregnant <12 weeks when blood was collected without explaining how this subset relates to the full study groups. The enrollment figure does not identify the number included in the endpoint analysis. Analysis populations, exclusions, missing-data procedures, and the primary statistical model are not reported.
The endpoint title lists ug/ml, while its unit field lists ug/l. The registry record does not resolve this discrepancy. It also lists secondary outcomes without reporting their results. Multiplicity handling, interim analyses, and the original sample-size justification are not reported. The planning assumptions are described as illustrations, not as the study’s own design, and do not substitute for a prespecified statistical plan.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Low Plasma Mannose Binding Lectin (p-MBL) Level is a Risk Factor for Recurrent Pregnancy Loss (RPL) — NCT04017754.
- Registry record last updated 2021-07-30; status last verified 2021-07.
- Results first posted 2021-02-24.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT04017754 is a completed observational study sponsored by Aalborg University Hospital. The registry lists a study start of 2016-01-01, primary completion of 2021-03-29, and enrollment of 452. The study concerns p-MBL levels in women with unexplained recurrent pregnancy loss and a reference group of Danish female blood donors.
The primary endpoint is plasma MBL level, described as a median with an inter-quartile range at first consultation. The record identifies 18 women who were pregnant <12 weeks at blood collection, but does not explain how this population relates to the full study sample. It lists secondary outcomes concerning birth weight, very low birth weight, preeclampsia, and emergency caesarean section.
The registry record does not report the primary endpoint values, a group comparison, or results for the secondary outcomes. It also does not report key analysis details, including missing-data handling and multiplicity procedures. The listed endpoint title and unit differ, and the record does not resolve that discrepancy.