NIDA CTN Protocol 0080 Medication treatment for Opioid use disorder in expectant Mothers (MOMs): a pragmatic randomized trial comparing extended-release and daily buprenorphine formulations 1.1 Study Objectives CTN?0080 includes four objectives: * Primary Objective: To evaluate the impact of treating opioid use disorder (OUD) in pregnant women with extended-release (XR) buprenorphine (BUP), compared to sublingual (SL) BUP, on mother and infant outcomes. Hypothesized outcomes are that the BUP-XR, relative to the BUP-SL, group will: 1) not have greater illicit opioid use during pregnancy (primary, non-inferiority); 2) have lower infant neonatal opioid withdrawal syndrome (NOWS) severity (key secondary, superiority); and 3) not have greater postpartum illicit opioid use (key secondary, non-inferiority). * Secondary Objective: To test conceptual models of the mechanisms by which BUP-XR may improve mother-infant outcomes, relative to BUP-SL. * Tertiary Objective: To determine the economic value of utilizing BUP-XR, relative to BUP- SL, to treat pregnant women. * Quaternary Objective: To evaluate the impact of BUP-XR, relative to BUP-SL, on infant neurodevelopment. 1.2 Study Design This is an intent-to-treat, two-arm, open-label, pragmatic randomized controlled trial. Eligible participants will be randomized in a 1:1 ratio to BUP-XR or BUP-SL, balancing on site, estimated gestational age (EGA) at time of randomization (6 weeks-18 weeks vs. 19 weeks-30 weeks), and whether they are on BUP-SL at the time of randomization (yes vs. no). Participants will be provided with study medication and attend weekly medication visits through 12 months postpartum. Participants will be invited to participate in the conceptual model assessment (CMA) sub-study, which will be used to evaluate the MOMs conceptual models. Infant caregivers will be invited to participate in the infant neurodevelopmental outcomes (INO) sub-study, which will include a 24-month child assessment. The INO data will be locked separately from the rest of the CTN?0080 database to allow CTN?0080 database lock following collection of the final (non-INO) CTN-0080 data point. 1.3 Study Population Approximately 200 pregnant women, recruited from approximately 10 sites, will be randomized into the trial. Sites that provide BUP to pregnant women in an office-based setting, offer BUP treatment following delivery for ≥12 months, and admit enough potentially eligible women to meet the target randomization rate (1.25 per month) are eligible. The study population will include pregnant women who have an EGA of 6-30 weeks at randomization, and, in the judgment of the treating provider, are good candidates for BUP-maintenance treatment. All randomized participants will be encouraged to participate in the CMA and INO sub-studies. 1.4 Treatments Participants randomized to BUP-XR will receive a weekly formulation of CAM2038 during pregnancy. During the 12-month postpartum phase, women who are breastfeedi...