Importance: Parents who receive a prenatal diagnosis of congenital heart disease may experience more short- and long-term stress than those who receive a postnatal diagnosis. To identify potential interventions to ameliorate that stress, the longitudinal emotional experience of parents must first be understood. Objective: To better understand parents' accounts of their own prenatal experience, particularly aspects they found to be stressful or challenging, and to identify strategies to improve support. Design, Setting, and Participants: This qualitative study included analysis of transcripts of audio recorded telephone interviews with pregnant mothers and their support persons, as applicable, who were referred to and seen at the Fetal Cardiology Clinic at Vanderbilt Children's Hospital from May 2019 to August 2019 with an initial likely diagnosis of complex congenital heart disease at any gestational age. Data analysis was conducted from August 2019 to November 2019. Main Outcomes and Measures: An applied thematic analysis approach was used to code and analyze professionally transcribed interviews. Coding and codebook revisions occurred iteratively; intercoder reliability was assessed and confirmed routinely. One author coded all transcripts; a second author independently reviewed one-fifth of the transcripts at fixed intervals to ensure that interrater reliability remained greater than 80%. Results: Twenty-seven individuals from 17 families participated in 42 phone interviews during pregnancy, 27 conducted at the first time point after the initial prenatal cardiology consultation and 15 at the second time point after a follow-up prenatal cardiology visit. Most interviewees were mothers (16 interviewees [59%]; median [interquartile range] age, 30.0 [27.3-34.8] years) or fathers (8 interviewees [30%)], with a few support individuals (3 interviewees [11%]) (median [interquartile range] age of family member or support individual, 30.0 [26.0-42.0] years). Initial fetal diagnoses included a range of severe congenital heart disease. Uncertainty was identified as a pervasive central theme and was related both to concrete questions on scheduling, logistics, or next steps, and long-term unknown variables concerning the definitiveness of the diagnosis or overall prognosis. Practitioners helped families through their framing of uncertainty at various time points including before, during, and after the clinic visit. Conclusions and Relevance: Families walk an uncertain path following a fetal diagnosis of severe congenital heart disease. The challenges faced by the cardiologists caring for them overlap in many ways with those experienced by pediatric palliative care practitioners. Potential future interventions to improve parental support were identified in the areas of expectation setting before the referral visit, communication in clinic, and identity formation after the new diagnosis.