Perinatal opioid use disorder is increasing. Integrated obstetric/addiction care models likely optimize parent-infant dyad outcomes, but the ideal combination of services is unknown. This study (1) describes pregnancy-to-postpartum service utilization by people receiving buprenorphine at an integrated Obstetric/Addiction Clinic and (2) explores the association between service utilization and postpartum buprenorphine continuation. This retrospective medical record review study uses research registry data from an outpatient Obstetric/Addiction Clinic. All patients are invited to participate in the research registry. For patients who consent, monthly medical record abstractions are conducted beginning with their first clinic visit to collect demographic, obstetric, and substance use disorder treatment variables. Present analyses included patients who delivered an infant between June 2019 and June 2021, started buprenorphine during pregnancy, and were receiving buprenorphine at delivery. Overall service utilization was the number of services (range 0-12) used between 28-weeks gestation and 12-weeks postpartum. Bivariate analyses and multivariable logistic regression assessed associations between service utilization and buprenorphine continuation. Participants (n = 42) were primarily non-Latinx White (67%) with comorbid psychiatric diagnoses (95%). On average, participants used 6 services; prenatal care, mental health care, and postpartum contraception were most utilized. Overall, 69% of participants continued buprenorphine at 6 months postpartum. This did not differ by level of service utilization (bivariate [ P = 0.07], multivariable [ P = 0.16]). Integrated care with a harm reduction focus supports pregnancy-to-postpartum service utilization and buprenorphine continuation in a patient sample at high risk for medication for opioid use disorder discontinuation. Further work is needed to identify evidence-based methods to individualize integrated obstetric/addiction care.