Background: Although treatment for opioid use disorder (OUD) often yields high adherence during pregnancy, the risk of returning to opioid misuse during postpartum is high. There are currently no relapse prevention programs tailored to this unique time period. Objectives: Using a prospective cohort study, we seek to identify hormones and/or infant caregiving approaches as predictors of postpartum opioid misuse. As a first step in dissemination of results, this report contains a detailed account of the protocol, as well as recruitment, retention, compliance, and participant satisfaction. Population: Participants were individuals with OUD (OUD+) and those without (OUD-) who were followed from late pregnancy (≥gestational week 36) to postpartum month five. Methods: From childbirth to postpartum week 12, participants completed daily surveys (capturing use, craving, interactions with infant) and weekly face-to-face visits (including collection of biological samples for hormone assays). Follow-up visits using the same procedures occurred at postpartum month four and five. Preliminary Results: A total of 50 OUD+ and 21 OUD- participants enrolled, 93% notified the study staff of childbirth, 87% completed at least one postpartum clinic visit, and 73% completed through postpartum month five. Compliance with procedures ranged from 66% for saliva samples and daily surveys to 78% for weekly surveys, generally with lower compliance among OUD+ and at later study time points. Participants, regardless of group and time point, reported high study satisfaction (e.g., on a scale where 0 is not at all and 3 is extremely, on average participants reported 2.9+/-0.4 for their willingness to complete this study again). Conclusions: This prospective cohort study was well tolerated despite the challenging postpartum period. Data collected will provide ample opportunities to identify novel risk/protective factors to inform the development of new relapse prevention intervention programs specific to the needs of those with OUD during early postpartum.

The authors have declared no competing interest.

This study was funded by National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health & Human Development (DP2HD105541) and National Center for Advancing Translational Sciences (UL1TR000445).

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Institutional Review Board at the University of Arizona gave ethical approval for this work.

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

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All data produced in the present study are available upon reasonable request to the authors.