Lifestyle Intervention in Preparation for Pregnancy (LIPP): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lifestyle Intervention in Preparation for Pregnancy (LIPP) (NCT03146156), a randomized na study. The primary outcome is Neonatal Adiposity Comparison Between Intervention and Usual Care Group.

2. Clinical Question

3. Trial Design

LIPP is a randomized, parallel-group trial with single masking. The registry record lists enrollment of 143 and identifies Tufts Medical Center as the sponsor. Its phase is listed as NA. The trial status is completed; the listed start date is 2017-03-21 and the listed primary completion date is 2025-08-31. These administrative details describe the registered study, but do not establish which participants contributed data to any particular outcome.

The intervention is a behavioral lifestyle program. Coaches are described as providing personalized instruction on physical activity, dietary data, and behavioral strategies. The comparator is usual care, including follow-up by the participant’s primary obstetrical provider and an offer of early-pregnancy nutrition counseling by a registered dietitian for overweight or obese women. The stated aim of that counseling is to support gestational weight gain within Institute of Medicine guidelines. The registry record does not report whether participants received all of these components or the degree of adherence in either group.

The primary endpoint is neonatal adiposity, measured through neonatal anthropometry and air densitometry, with the assessment scheduled at 48 to 72 hours after delivery. The endpoint description explicitly says that this outcome was not measured for mothers. Maternal metabolic status, lactation duration, and human milk macronutrient composition are listed as secondary outcomes. Although the record lists four outcome measures, it reports 0 analyses. It also notes that the primary outcome has several categories or time points and was not reduced to one comparison. Thus, the design and intended outcome can be described, but a single primary-outcome result cannot be interpreted from the registry record.

The masking designation is single, but who was masked is not reported in the registry record. Further allocation procedures, protocol details, and the statistical analysis plan 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.

Before assignment: Mothers and neonates were both enrolled. Mothers could only have a singleton pregnancy, for this study. All participants had at least 1 previous pregnancy before being enrolled. No subsequent pregnancies were part of this study. Not all enrolled participants had a pregnancy as part of the study.

Overall Study

Analysis population for the primary outcome, as defined in the registry: This outcome was not measured for the mothers.

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: Baseline race and sex are reported for all women who were enrolled in the study. Gestational age is only reported for those individuals who became pregnant during the study. Gestational age is not relevant for women who did not become pregnant during the study. Race of the neonates who were delivered during study participation were not included in the data collection.

6. Primary Endpoint

The registry lists the primary outcome as Neonatal Adiposity Comparison Between Intervention and Usual Care Group, measured over 48 to 72 hours after delivery.

The primary endpoint is a comparison of neonatal adiposity between the lifestyle-intervention and usual-care groups. The registry describes the measure as a mean in grams and identifies neonatal anthropometry and air densitometry (pea pod) as the assessment methods. Measurement is scheduled at 48 to 72 hours after delivery. The registry record says this outcome was not measured for mothers.

Neonatal adiposity is relevant to the trial’s stated research question because the intervention is intended to begin before conception and the rationale describes potential effects on maternal metabolism and placental or fetal growth. The endpoint focuses on the newborn rather than on maternal weight change or gestational weight gain. The registry record also lists maternal metabolic status, lactation duration, and human milk macronutrient composition as secondary outcomes, but those are distinct from the primary neonatal endpoint.

A mean describes the average value in a group, while a standard deviation describes the spread of individual observations around that group’s mean. For a between-group comparison, an estimated difference in means would describe the contrast in average adiposity. A confidence interval, if reported, would show the range of values compatible with the data under the analysis assumptions and indicate the precision of the estimate. Neither group means, a between-group estimate, nor its confidence interval is reported as a single primary comparison in the registry record. The endpoint’s definition therefore does not by itself establish the size, direction, or precision of a treatment-group difference.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical concepts relevant to this trial can be described, but the registry record does not report a complete analysis plan or a single primary-outcome analysis. The distinction matters: a planned endpoint and a statistical method are not the same as a posted estimate. General explanations below describe how such methods are ordinarily interpreted, not analyses confirmed for LIPP.

What does a mean and standard deviation describe?

The primary outcome is described as a continuous measure in grams, summarized by a mean and standard deviation. In general, a mean represents the average of the measured values in a group. The standard deviation describes how dispersed individual measurements are around that average. A standard deviation is not the uncertainty of the mean and is not a confidence interval. To understand a group comparison, readers would need the group summaries and an estimate of the between-group contrast, along with an indication of its uncertainty. Those primary-outcome results are not reported in the registry record.

What would a confidence interval add?

In general, a confidence interval conveys the precision of an estimate under the assumptions of the statistical method used. A relatively narrow interval indicates more precision than a wide interval, while an interval spanning a range of possible effects leaves greater uncertainty about the size and direction of the contrast. It does not show that all values inside the interval are equally likely, nor does it establish that an outcome is clinically important. No confidence interval for a single primary comparison is reported in the registry record, so precision cannot be judged for that comparison.

How should a p-value be understood?

In general, a p-value describes how compatible the observed data are with a specified null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not quantify the size of an effect. A small p-value alone would not show that a difference is important; a large p-value would not prove that the groups are identical. The registry record does not report a p-value for a single primary-outcome comparison. No inference about statistical significance can therefore be made from the primary-outcome information described.

Why do randomization and masking matter?

Random allocation is intended, in general, to make treatment groups comparable with respect to measured and unmeasured characteristics before assignment, subject to the actual conduct of the trial. It does not guarantee that the groups will be identical, particularly in a finite study, and it does not resolve missing outcome data or measurement limitations. The record identifies the allocation as randomized and the design as parallel. It also lists single masking, but who was masked is not reported in the registry record. Details of sequence generation, concealment, and masking procedures are not reported in the registry record.

What do the planning assumptions mean?

The stated sample-size planning framework is an illustration based on the observed effect, not the trial’s own design justification. Its assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. A planning calculation of this kind asks how many participants per arm would be needed under its assumptions to target a specified power; it is not an observed result or evidence that the trial had that power. The actual planning illustration counts are not reported in the registry record. The effect used for that illustration and the trial’s own sample-size justification are not reported in the registry record.

In general, planning estimates depend on assumptions about the target effect, outcome variability, allocation, and statistical procedure. If an observed effect is used as a starting point, the resulting illustration can be sensitive to that estimate, especially when the estimate is imprecise. Planning for a fraction of an observed effect represents a different target contrast from planning for the full observed effect. These calculations should not be described as observed power, and they do not tell readers what the trial found.

What does the endpoint structure imply?

The registry record says the primary outcome has several categories or time points and was not reduced to one comparison. A statistical analysis could, in general, define a particular summary, comparison, or model for repeated or categorical measurements. The choice affects the interpretation, and selecting among multiple comparisons can also affect the chance of false-positive findings. The registry record does not report which comparison was designated for analysis, how categories or time points were handled, or whether a particular model was used. No such method should be inferred from the endpoint description alone.

Over-dispersion is a general issue for some count outcomes: it occurs when observed variation exceeds what a chosen model assumes, potentially making standard errors too small if ignored. The primary endpoint is described as a continuous mean in grams, not a count. There is no basis in the registry record to claim that over-dispersion was assessed or that a particular model requiring such an assessment was used.

More broadly, the registry record does not report the primary analysis model, covariate adjustment, treatment of missing values, analysis population, or handling of protocol deviations. These details affect how a numerical estimate should be understood. Without a single reported endpoint estimate and a description of its analysis, general statistical principles can clarify what would be useful to report, but cannot supply the missing result.

10. Multiplicity, Missing Data and Analysis Populations

The record lists four outcome measures. Alongside neonatal adiposity as the primary outcome, it names maternal metabolic status, lactation duration, and human milk macronutrient composition as secondary outcomes. Considering multiple outcomes, categories, or time points raises a general multiplicity issue: when many statistical comparisons are made, the chance of at least one apparently unusual result can increase. Researchers may address this through prespecification, adjustment, or a hierarchy of outcomes. Which approach was used for LIPP is not reported in the registry record.

The primary outcome is specifically described as having several categories or time points and not being reduced to one comparison. This makes the absence of a defined single result important for interpretation. The record does not identify the categories or time points used in an analysis, explain how comparisons were selected, or describe any multiplicity adjustment. The registry record does not report whether an analysis plan specified a primary contrast in more detail.

Missing-data methods and analysis populations also affect the interpretation of a randomized trial. The registry record does not report the number of participants with primary-outcome measurements, the reasons for any missing measurements, or how missing values were handled. It does not state whether analyses used all randomized participants, participants with observed outcomes, or another defined population. Overall enrollment of 143 cannot substitute for an endpoint-specific denominator.

Interim analyses and stopping rules are not reported in the registry record. The record also does not report a protocol or statistical analysis plan that would clarify these decisions. These omissions do not establish that particular procedures were or were not used; they mean that their role cannot be assessed from the registry record.

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 5% reporting threshold.

The posted safety figures list 0 serious adverse events among 21 participants at risk in Usual Care, and 0 among 23 participants at risk in Lifestyle Intervention/Mothers. Deaths are recorded as 0 in each of those groups. The record also lists 0 other adverse events among 21 at risk in Usual Care and 0 among 23 at risk in Lifestyle Intervention/Mothers. These values are counts within the safety summaries, not estimates of the primary neonatal adiposity outcome.

The at-risk counts should be read as the denominators attached to those group-specific safety entries. The registry record does not explain why those counts differ from overall enrollment of 143, define the safety follow-up period, or describe whether all participants were assessed in the same way. It does not report the event-collection procedures or provide a list of serious adverse-event terms; the listed top serious terms are empty.

Zero recorded events in these entries means no events are recorded for these group summaries. It does not establish that no event occurred anywhere in the trial, nor does it demonstrate equal safety between groups. The safety counts are limited to the populations and events represented in the registry record; they do not support a broader conclusion about safety or replace a complete safety analysis.

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

The registry record identifies a clinically focused research question: whether a lifestyle intervention initiated before a planned pregnancy can affect neonatal adiposity compared with usual care. It describes the intervention, comparator, and a measurement approach based on neonatal anthropometry and air densitometry at 48 to 72 hours after delivery. These details clarify what the trial intended to study.

They do not establish the result. The registry record reports no single primary-outcome comparison, and it does not give an estimate of the between-group difference, its confidence interval, or a p-value. The primary endpoint is noted as involving several categories or time points, without being reduced to one comparison. Consequently, the direction, size, and precision of a primary result cannot be determined from the posted outcome information.

The record’s stated rationale refers to prior concerns about gestational weight gain, maternal metabolism, placental and fetal growth, and neonatal outcomes. That background explains the motivation for studying an intervention before conception. It should not be mistaken for evidence that the LIPP intervention changed neonatal adiposity. The listed secondary outcomes likewise identify additional topics of interest; they are not results.

The registry status is completed, and enrollment is listed as 143. Neither fact indicates that all enrolled participants contributed to every outcome, or that a particular effect was observed. Endpoint-specific participation and missing-data information are not reported in the registry record. The safety summaries report no recorded serious adverse events or deaths within their listed groups, but they are limited group-specific counts and do not establish overall safety.

In general, a treatment-group estimate is most informative when interpreted with its uncertainty, the analysis population, missing-data handling, and prespecified comparison. Those details are not reported for a single primary analysis in the registry record. The reasonable conclusion is therefore limited: the registry documents a randomized parallel-group study and its intended neonatal outcome, but the posted information does not permit an estimate of the intervention’s effect on that outcome. It neither demonstrates a difference nor demonstrates that the groups were equivalent.

13. Why This Trial Matters Statistically

This trial raises a statistical question about timing and outcome selection. Its stated intervention is intended to begin before conception, while the primary endpoint is neonatal adiposity measured after delivery. That design links a behavioral intervention to a newborn outcome, but interpretation depends on a clearly specified comparison and complete reporting of the outcome analysis. The registry record describes the endpoint and its timing, yet does not report a single primary-outcome comparison.

The trial is also a useful example of why a stated outcome is not the same as a reported result. The endpoint is described as a mean in grams, with a standard deviation as the dispersion measure, and the measurement methods are named. But without group summaries and a between-group estimate, readers cannot judge the magnitude or precision of a contrast. The record’s note that several categories or time points were not reduced to one comparison further emphasizes the importance of a clearly identified estimand: the specific quantity a study intends to estimate.

Randomization and parallel allocation provide a framework for comparative inference, but they do not remove the need to report who was analyzed, how missing outcomes were handled, and which comparisons were prespecified. Those details are not reported in the registry record. They matter because a numerical result can be interpreted only in relation to the participants and methods that produced it.

Finally, the distinction between planning and findings is central. The record describes planning assumptions based on an observed effect, but a planning illustration is not a trial result and cannot establish observed power. The trial’s own sample-size justification is not reported in the registry record. Keeping these limits visible prevents design information, study rationale, and sparse safety counts from being mistaken for evidence about the primary neonatal outcome.

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 main trial-specific limitation for interpretation is that the registry record does not report a single primary-outcome comparison. It notes several categories or time points for neonatal adiposity and says the outcome was not reduced to one comparison. There are no reported group means, standard deviations, effect estimate, confidence interval, or p-value for a single primary result. The size and precision of any between-group difference therefore cannot be assessed.

The record lists overall enrollment of 143, but does not report how many participants or newborns contributed measurements to the primary outcome. Reasons for missing measurements and methods for handling missing data are not reported in the registry record. The analysis population is also not reported. It is therefore not possible to assess attrition for this endpoint or determine how the analyzed participants relate to the randomized groups.

Further methodological details that would guide interpretation are absent from the registry record. These include the statistical model, any covariate adjustment, multiplicity procedures, interim analyses, and the trial’s own sample-size justification. The masking designation is single, but the masked parties are not identified. These gaps do not establish that methods were inadequate; they limit what can be verified from the record.

The safety summaries are confined to the listed groups and counts. Their follow-up period and ascertainment procedures are not reported. The counts should not be generalized beyond those entries. Finally, the intervention and usual-care descriptions do not report intervention duration, adherence, or counseling uptake. These missing implementation details limit assessment of what participants actually received, separate from the absence of a primary endpoint analysis.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Lifestyle Intervention in Preparation for Pregnancy (LIPP) — NCT03146156.
• Registry record last updated 2026-10-08; status last verified 2026-09.
• Results first posted 2026-10-08.
• 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

NCT03146156, Lifestyle Intervention in Preparation for Pregnancy (LIPP), is registered as a completed, randomized, single-masked, parallel-group trial sponsored by Tufts Medical Center. Enrollment is listed as 143, the phase as NA, the start date as 2017-03-21, and the primary completion date as 2025-08-31.

The intervention is behavioral lifestyle coaching; the comparator is usual care, including an offer of early-pregnancy nutrition counseling for overweight or obese women. The primary outcome is neonatal adiposity, described as a mean in grams measured using anthropometry and air densitometry at 48 to 72 hours after delivery. Maternal metabolic status, lactation duration, and human milk macronutrient composition are listed as secondary outcomes.

The record lists 0 analyses and says the primary outcome’s several categories or time points were not reduced to one comparison. A single primary-outcome estimate and its precision are not reported in the registry record. Safety entries list 0 serious adverse events and 0 deaths in each of the two named groups, with 21 and 23 participants at risk, respectively.