BACKGROUND:Young breast cancer survivors (YBCS) have unmet needs for managing hot flashes, fertility-related concerns, sexual health, and contraception. PURPOSE:Describe the design and participant characteristics of a randomized controlled trial testing the efficacy of the survivorship care plan on reproductive health (SCP-R) intervention on improving hot flashes, fertility-related concerns, sexual health, and contraception in YBCS. METHODS:SCP-R is a web-based intervention with text message support encompassing evidence- based practices on four reproductive health issues. YBCS with ≥1 reproductive health issue are randomized to intervention (full SCP-R access) or attention control (access to list of online resources) arms with 24-week follow-up. The primary outcome will be improvement of at least one reproductive health issue measured by validated self-report instruments. Each YBCS nominated one healthcare provider (HCP), who can access the same materials as their patient. HCP outcomes are preparedness and confidence in discussing each issue. RESULTS:Among 318 YBCS screened, 57.2% underwent randomization. Mean age was 40.0 (SD 5.9), and mean age at cancer diagnosis was 35.6 (SD 5.4). Significant hot flashes, fertility-related concerns, vaginal symptoms, and inadequate contraception were reported by 50.5%, 50%, 46.7%, 62.1% of YBCS, respectively; 70.9% had multiple issues. Among 165 nominated HCPs, 32.7% enrolled. The majority of HCPs reported preparedness (68.5-90.7%) and confidence (50.0-74.1%) in discussing reproductive health issues with YBCS. HCPs were least likely to report preparedness or confidence in discussing fertility-related concerns. CONCLUSION:Conducting a trial for improving YBCS reproductive health online is feasible, providing a mechanism to disseminate evidence-based management.