Labor and Delivery Implant Insertion: A Randomized Controlled Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Labor and Delivery Implant Insertion: A Randomized Controlled Trial (NCT02866643), a randomized phase 3 study. The primary outcome is Time to Lactogenesis Stage II [Questionnaire].

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group, phase 3 trial with no masking. The study compared two implant insertion schedules rather than implant use with no implant: insertion 0-2 hours after delivery in the delivery room, or insertion 24-48 hours after delivery in a postpartum room before discharge. Allocation was randomized, but participants and clinical staff were not masked according to the registry record. The record identifies Stanford University as the sponsor.

The registry reports enrollment of 95. Its brief description states that the investigators planned to randomize 82 consenting women. The registry record does not explain the relationship between the enrollment figure and the number in that description. For the primary analysis, the stated population was per protocol: participants who received the implant at the protocol-specified time point. The primary outcome results include 35 participants in each arm.

Primary-outcome monitoring was described as daily in the first seven days postpartum, or until lactogenesis was reported, beginning at 24 hours following delivery. The registry says the study used questionnaires about breastfeeding continuation, supplementation, duration, and exclusivity, as well as contraceptive continuation, satisfaction, pregnancy, and postpartum care visits. The status is completed. The registry record does not report the original sample-size justification, detailed allocation procedures, or a statistical analysis plan. It also does not report interim analyses.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Per Protocol Population (received implant at protocol-specified time point)

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: Per Protocol Population (received implant at protocol-specified time point)

6. Primary Endpoint

The registry lists the primary outcome as Time to Lactogenesis Stage II [Questionnaire], measured over Participants will be monitored daily by the research staff, in the first seven days postpartum, or until lactogenesis reported, beginning at 24-hours following delivery, to determine time to lactogenesis stage II..

The primary endpoint was time to lactogenesis stage II, measured in hours. Lactogenesis stage II was defined in the registry as the initiation of copious milk secretion as documented by the participant's perception. The investigators described using a set of specific validated questions to establish when participants perceived this change, then relating that time to the documented time of delivery.

This endpoint addresses the trial's central timing question: whether implant insertion immediately after delivery, rather than later before discharge, is associated with a different time to the onset of perceived copious milk secretion. Measuring time in hours retains information about when the event was reported, rather than reducing the outcome to whether it occurred by a single cutoff. The registry specifies daily monitoring during the first seven days postpartum, beginning at 24 hours after delivery, until lactogenesis was reported or the monitoring period ended.

The posted outcome is a continuous measure summarized by a mean and standard deviation. The stated primary population is per protocol, restricted to participants who received the implant at the protocol-specified time. Because the event is defined by maternal perception and questionnaire responses, the endpoint reflects perceived onset as operationalized by the study, not a separately described objective measurement of milk production.

7. Results Posted in the Registry

• Postpartum Insertion: mean 67.50 versus 65.00 on control; difference 2.50 (95% CI -11.98 to 16.98), standardized effect d = 0.08; z-test p = 0.735.

8. Secondary Efficacy Endpoints

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

Number of Participants Still With the Contraceptive Implant at Month 12.

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Postpartum Insertion: 85.7% (12/14) versus 93.3% (14/15) on control; risk difference -7.6 percentage points (95% CI -29.9 to 14.6), risk ratio 0.92 (0.71–1.18); unadjusted two-proportion z-test p = 0.501.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Postpartum Insertion and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants Satisfied or Very Satisfied With Implant Contraceptive

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Postpartum Insertion: 62.5% (10/16) versus 88.9% (16/18) on control; risk difference -26.4 percentage points (95% CI -54.2 to 1.4), risk ratio 0.70 (0.47–1.06); unadjusted two-proportion z-test p = 0.070.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Postpartum Insertion and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants Reporting a Pregnancy Within 12 Months

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Postpartum Insertion: 2.9% (1/35) versus 2.9% (1/35) on control; risk difference 0.0 percentage points (95% CI -7.8 to 7.8), risk ratio 1.00 (0.07–15.36); unadjusted two-proportion z-test p = 1.000.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Postpartum Insertion and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes address several distinct aspects of postpartum experience: breastfeeding, implant continuation, satisfaction, pregnancy, and postpartum care. The posted results cover implant continuation at month 12, satisfaction at month 12, and pregnancy within 12 months. Results for the other secondary outcomes listed in the study description are not reported in the registry record. The secondary findings therefore provide only a partial picture of the broader outcomes the study intended to examine.

Across the posted secondary outcomes, the pattern is not uniform: the group comparisons differ in their point estimates and in the amount of uncertainty. Their denominators also vary by outcome. This variation means that the results should not be treated as though each comparison represents the same participants or has the same precision. Differences among endpoints do not resolve the primary lactogenesis comparison, which measures a different outcome and uses a per-protocol population.

In general, secondary outcomes can help describe whether the randomized groups show similar or differing patterns beyond the primary question. They are less conclusive when multiple endpoints are examined without a reported plan for prioritization or multiplicity adjustment. An unadjusted p-value addresses a single comparison under its statistical assumptions; considering many such values increases the chance that at least one will appear noteworthy by chance. The registry record lists no investigator-reported analyses for these secondary outcomes, and does not report a multiplicity strategy. Accordingly, the secondary results are best read as descriptive and exploratory rather than as independent confirmations of the primary result.

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

• Number of of Participants Actively Breastfeeding
• Number of Participants Still With the Contraceptive Implant at Month 12.
• Number of Participants Satisfied or Very Satisfied With Implant Contraceptive
• Number of Participants Reporting a Pregnancy Within 12 Months
• Number of Participants Attending a Postpartum Care Visit by Month 3

9. Statistical Interpretation

10. Statistical Methods Explained

The registry presents a randomized, parallel-group comparison. In a randomized trial, assignment is intended to create groups whose baseline characteristics are comparable on average; randomization does not guarantee identical groups, especially in a trial of limited size. A parallel-group design means that participants were assigned to one of the two insertion schedules, rather than crossing between schedules. The record says the trial was unmasked, so participants and study personnel were not described as unaware of the assigned timing.

What does a difference in means represent?

The primary outcome is continuous: elapsed time to perceived lactogenesis stage II, measured in hours. The posted group summaries are means with standard deviations. The mean describes the average observed time in each arm, while the standard deviation describes how spread out individual times were around the mean. The reported comparison subtracts the Delivery Room Insertion mean from the Postpartum Insertion mean. A positive difference therefore indicates a higher mean time in the postpartum-insertion group in this stated comparison direction. The estimate is 2.5 hours.

A mean difference preserves the outcome's original unit, which makes it possible to interpret the estimate on the hours scale. It is not an adjusted estimate: the recalculated comparison is an unadjusted comparison of the posted summary statistics. The registry record does not report a covariate-adjusted primary analysis or a model used by the investigators. The sponsor's own analysis would take precedence if a discrepancy were identified; no discrepancy is identified in this record.

How should the confidence interval be read?

A confidence interval describes the uncertainty around an estimated effect under the method used to construct it. In general, a wider interval represents less precision than a narrower one. The primary interval, -11.98 to 16.98 hours, includes values on both sides of zero. Zero represents no difference in means under the comparison's scale. The interval is not a list of effects that are equally likely, and it does not guarantee that the true effect lies within its limits. It communicates how much uncertainty remains in the estimate under the interval procedure.

The record posts an unadjusted p-value of 0.735 for the primary comparison. In general, a p-value measures how unusual data at least as discrepant as those observed would be if a specified null hypothesis and statistical model were correct. It is not a measure of clinical importance, the probability that a result is chance, or evidence of equivalence. The registry record does not report a threshold used for the primary outcome's hypothesis test or a detailed testing plan.

What do binary outcome measures express?

Several posted secondary outcomes count participants with an outcome, such as retaining the implant at month 12, reporting satisfaction, or reporting pregnancy within 12 months. For a binary outcome, a risk difference compares the proportions in the two arms by subtraction. A risk ratio compares those proportions as a ratio, and an odds ratio compares the odds of an outcome. These measures answer different questions and can differ in magnitude and interpretation. Confidence intervals for such measures express uncertainty, and an interval for a ratio is interpreted relative to one, while an interval for a difference is interpreted relative to zero.

The secondary comparisons are unadjusted in the posted recalculations, and no investigator-reported analyses are listed. These results should therefore be treated as descriptive comparisons rather than as a confirmed set of hypothesis tests. When many outcomes are examined, some apparent differences can arise by chance even if there is no underlying difference. An analysis plan may specify how to prioritize outcomes or address multiplicity; that plan is not reported in the registry record.

Why does the analysis population matter?

The primary endpoint is reported for a per-protocol population defined as participants who received the implant at the specified time. This is not necessarily the same population as all participants randomized. A per-protocol analysis can describe outcomes among participants who followed the assigned schedule, but excluding participants after randomization can weaken the protection randomization provides if exclusions relate to outcomes or other participant characteristics. The registry record does not report the number excluded from this primary population, the reasons, or an intention-to-treat analysis. The analysis population should therefore be kept in view when interpreting the comparison.

The posted denominators also vary among secondary outcomes. Different denominators can reflect different outcome-specific availability or eligibility, but the reasons for these particular denominators are not reported in the registry record. Without a description of missing-data handling, it is not possible to determine whether missing responses were balanced between arms or how they may affect the estimates.

What can be inferred from the posted methods?

General statistical interpretation depends on how outcomes were collected, how participants were analyzed, and how uncertainty was calculated. The registry specifies the primary outcome definition, the per-protocol population, and the group summaries, but it does not report the investigator's full statistical methods. The recalculated comparison is a simple unadjusted analysis of the posted summaries; it should not be confused with an analysis plan authored for the trial. No interim analyses, missing-data method, or detailed model specification is reported in the registry record.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data estimate the difference between groups. The primary mean difference is 2.5 hours, with a 95% confidence interval from -11.98 to 16.98 hours. The interval extends in both directions from zero, so the posted results are compatible with a range of possible group differences rather than pinpointing a single value. The point estimate is the center of the reported comparison, but it is not by itself a complete account of uncertainty.

The arm-specific standard deviations are 25.1 hours for Delivery Room Insertion and 35.8 hours for Postpartum Insertion. These values describe variation among observed times within each group; they are not confidence intervals around the group means. The primary outcome has 35 participants per arm. The registry does not provide arm-specific confidence intervals for the means, and the posted record does not explain the interval calculation in detail.

For general interpretation, a confidence interval is a range generated by a statistical procedure that reflects sampling uncertainty under its assumptions. A broad interval can result when the estimate is uncertain relative to the variability and amount of data. It should not be read as proving that every value inside the interval is plausible to the same degree, or that values outside it are impossible. The primary interval's inclusion of zero means that the posted comparison does not precisely distinguish a positive from a negative mean difference. It also does not establish equivalence, since an equivalence conclusion requires a prespecified acceptable range and an analysis designed for that question; such a range is not reported in the registry record.

Other posted outcomes also have uncertainty intervals, and their denominators differ. The registry record does not report a common missing-data approach or a complete analysis plan that would clarify the precision of all outcomes together. Statistical precision is distinct from practical importance: the registry does not state a threshold for a meaningful difference in time to lactogenesis.

12. Planning a Similar Trial: Sample Size

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

The sample-size figures are planning illustrations based on the observed effect, not the trial's original design justification. For the continuous primary outcome, the figures are participants per arm. The record's planning assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; each row uses the stated fraction of the observed effect as the effect to detect. For time-to-event planning, figures would refer to total events using the Schoenfeld method, while other outcomes are expressed as participants per arm. The primary endpoint reported in this trial is a continuous mean, so its planning figures are participants per arm.

The 80% power column describes a planning target under which the assumed study design would have an 80% probability of detecting the specified effect if that effect were the true effect and the planning assumptions held. The 90% power column describes the corresponding 90% target. These are design calculations, not guarantees about a future study's result. Smaller assumed effects require more participants to reach the same power target, which is why the planning rows based on smaller fractions of the observed effect require larger sample sizes.

The figures use the observed estimate, which is uncertain and may not represent the effect in another study. They should not be treated as an estimate of the number needed for a definitive study without considering the intended effect, outcome variability, analysis plan, and other design choices. The registry record does not report the trial's own sample-size justification or original design assumptions. These calculations are not observed power.

13. How the Sample Size Is Derived

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

Formula

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

Worked calculation for this trial

1. Observed difference Δ = 2.500; pooled standard deviation σ = 30.916.
2. n = 2 × (1.96 + 0.842)² × 30.916² / 2.500² = 2,400.7, rounded up to 2,401 participants per arm for 80% power.

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

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 2.5                      # observed difference in means
sigma <- 30.9164195857153                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

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

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2866643)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 2,401 (80% power), 3,214 (90% power)
 75% of observed effect: n per arm = 4,268 (80% power), 5,714 (90% power)
 50% of observed effect: n per arm = 9,603 (80% power), 12,856 (90% power)
power.t.test: 2401.7 
Simulated power at n = 2,401 per arm: 0.804 (20000 replicates)

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

14. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple outcomes spanning lactogenesis, breastfeeding, implant continuation, satisfaction, pregnancy, and postpartum care. When several outcomes or comparisons are assessed, multiplicity becomes relevant: the more questions examined, the greater the opportunity for a chance finding among them. Statistical plans can address this by identifying a primary outcome, specifying an order of testing, adjusting significance thresholds, or clearly labeling additional analyses as exploratory. The primary outcome is identified in the registry, but a multiplicity strategy is not reported in the registry record.

The registry record lists no reported analyses for the secondary outcomes. The posted unadjusted comparisons therefore should not be interpreted as though they were protected by a documented family-wise testing plan. The primary result remains the designated primary endpoint, but the record does not provide enough information to determine how the investigators handled all planned analyses or whether the posted outcome set captures every analysis conducted.

Missing-data handling is also not reported. The secondary denominators differ across outcomes, and the record does not explain why. It does not state how unanswered questionnaires, unavailable follow-up, or other missing outcome information were treated. This absence does not establish that data were missing; it means the registry record does not report their status or management. Without those details, readers cannot assess whether missingness could have affected the comparisons.

The primary population is described as per protocol, defined by receipt of the implant at the specified time point. The registry does not report how many randomized participants were excluded from this population, the reasons for any exclusions, or results from an analysis of all randomized participants. It also does not report an intention-to-treat analysis. These omissions limit assessment of how closely the primary comparison preserves the advantages of random allocation.

The record does not report the original sample-size justification, interim analyses, or a detailed statistical analysis plan. Such information would clarify how the outcomes and analysis populations were selected and how uncertainty and multiple testing were addressed. Their absence from the registry record limits what can be concluded about prespecification, but does not by itself show that the study lacked such procedures.

15. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry reports serious adverse event figures for 48 participants at risk in Delivery Room Insertion and 47 at risk in Postpartum Insertion. No serious adverse events are reported as affecting participants in either group, and deaths are reported as zero in both groups. The record also reports no other adverse events affecting participants in either group.

These figures describe the entries in the registry record; they do not establish that no events occurred outside the reported scope or follow-up. The safety denominators differ from the 35 participants per arm in the primary per-protocol outcome. The registry record does not explain the relationship between these denominators or describe the safety ascertainment period in detail. No serious adverse event terms are listed. The figures should therefore be read as reported counts and denominators, not as a complete independent assessment of safety or as a comparison designed to rule out uncommon events.

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

The result answers a focused statistical question about the mean time to maternal perception of lactogenesis stage II under two implant insertion schedules. The posted means were 65.0 hours for delivery-room insertion and 67.5 hours for postpartum-ward insertion. The estimated difference was 2.5 hours, with a confidence interval extending from -11.98 to 16.98 hours. These values describe the observed per-protocol data and the uncertainty around the unadjusted comparison.

The results do not establish that the schedules have identical effects. A failure to distinguish a difference in this sample is not the same as evidence of equivalence; equivalence requires a prespecified margin and a design and analysis directed at that question. Nor do the results show that either schedule causes a particular change in lactogenesis. The groups were randomized, but the primary result is reported for a per-protocol population and the record does not report an all-randomized analysis.

The endpoint is maternal perception of copious milk secretion, collected through questions and daily monitoring beginning 24 hours after delivery. It is not described as an objective laboratory measurement. The findings consequently concern the endpoint as measured, not every dimension of breastfeeding or milk production. Although the study description includes other breastfeeding and postpartum topics, results for all listed outcomes are not reported in the registry record.

The registry's secondary outcomes offer additional descriptive information, but they involve different endpoints and denominators and are unadjusted. The registry does not report a multiplicity plan or the full missing-data and analysis methods. This limits the strength of conclusions that can be drawn across those outcomes. The meaning of the posted results is therefore bounded: they estimate a between-group difference in the specified primary measure, with substantial uncertainty, in the stated analysis population. They do not settle broader questions about all postpartum outcomes or establish that one approach is preferable.

17. Why This Trial Matters Statistically

This trial is statistically interesting because it separates the question of implant use from the question of insertion timing. Both randomized arms received an implant; the contrast was immediate insertion in the delivery room versus insertion later in the postpartum ward before discharge. That design makes the timing contrast central to interpretation, while leaving other comparisons outside the trial's randomized question.

The primary measure also illustrates how an outcome definition shapes an estimate. Lactogenesis stage II was defined by maternal perception of copious milk secretion, elicited through questions and related to delivery time. This makes the endpoint relevant to the study's stated concern, while also making clear that the statistical result pertains to perceived onset as measured by the study.

Another useful statistical lesson is the difference between an estimate and its precision. The reported mean difference is 2.5 hours, but its confidence interval spans values on either side of zero. A point estimate alone can sound more definite than the data warrant; interval estimates show the uncertainty that should accompany it. The unadjusted p-value does not replace that uncertainty description and does not prove equality.

The record also illustrates why analysis populations, outcome-specific denominators, and reporting plans matter. The primary outcome is per protocol, secondary denominators vary, and the registry lists no reported secondary analyses or multiplicity strategy. These details affect how readers weigh comparisons, even when the numerical summaries are straightforward. The planning calculations further show that sample-size illustrations based on an observed effect are distinct from the original design rationale and from evidence about the results actually observed.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The primary outcome is based on participants' perception of copious milk secretion. Although the registry describes specific validated questions, perception is not an objective measurement of milk volume, and the finding applies to the endpoint as defined. Monitoring was described as daily, beginning at 24 hours postpartum and continuing through the first seven days or until lactogenesis was reported. A daily assessment schedule may not identify the exact moment an event began; the record does not describe more detailed timing procedures.

The primary analysis population was per protocol. The registry does not report the number of participants excluded from that population, reasons for exclusion, or an analysis of all randomized participants. This limits assessment of whether post-randomization exclusions could have influenced the comparison. The registry also reports 95 enrolled, while the study description says 82 women were planned for randomization; the record does not explain that difference.

Secondary outcome denominators differ, and the reasons are not reported. The registry lists several secondary outcomes for which results are not posted, leaving the reported secondary findings incomplete relative to the outcomes described. It also lists no reported analyses for the posted secondary outcomes. A multiplicity plan, missing-data approach, interim analyses, original sample-size justification, and detailed statistical analysis plan are not reported in the registry record.

The trial was unmasked. The primary endpoint relies on participant report, and the registry does not describe whether or how awareness of insertion timing was addressed in outcome collection. The posted primary interval is broad, so the estimate is not highly precise. These limitations concern interpretation of the registry results; the record does not establish that any one of them changed the findings.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Labor and Delivery Implant Insertion: A Randomized Controlled Trial — NCT02866643.
• Registry record last updated 2022-07-25; status last verified 2022-06.
• Results first posted 2020-09-29.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

NCT02866643 is a completed, randomized, parallel-group phase 3 trial sponsored by Stanford University. It compared etonogestrel implant insertion in the delivery room 0-2 hours after delivery with insertion in a postpartum room 24-48 hours after delivery, before discharge. The trial was unmasked and enrolled 95 participants; the study description states that 82 consenting women were planned for randomization.

The primary endpoint was time to lactogenesis stage II, defined by maternal perception of copious milk secretion and reported as a mean in hours. The primary results are for a per-protocol population, with 35 participants in each arm. The estimated mean difference was 2.5 hours, with a 95% confidence interval of -11.98 to 16.98 hours and an unadjusted p-value of 0.735. The registry also posts selected implant, satisfaction, and pregnancy outcomes. Further details on the original sample-size rationale, missing-data handling, multiplicity, and full analysis plan are not reported in the registry record.