Abstract Objective: To examine the impact of a Patient and Public Involvement exercise on the development of British Congenital Cardiac Association Fetal Cardiology Standards 2021. Design: Open-ended, semi-structured interviews were undertaken to inform the design of a study to improve the quality of parents’ experiences during antenatal and perinatal care of their child with CHD. This Patient and Public Involvement exercise was used to inform the final version of the drafted ‘Standards’. Setting: One-on-one interviews with parents who responded to a request on the closed Facebook page of the user group “Little Hearts Matter”: “Would you be interested in helping us to design a study about parents’ experience on learning that their child had CHD”? Patients: Parents of children with single ventricle CHD. Results: Twenty-one parents (18 mothers, 3 fathers) participated. Parents responses were reported to have variably reinforced, augmented, and added specificity in the later stages of drafting to six of the seven subsections of Section C Information and Support for Parents including: “At the time of the Scan”; “Counselling following the identification of an abnormality”; “Written information/resources”; “Parent support”; “Communication with other teams and ongoing care”; and “Bereavement support”. Conclusions: This Patient and Public Involvement exercise successfully informed the development of Standards after the initial drafting. It contributed to the establishment of face validity of the ‘Standards’, especially when consistent with what is reported in the literature. Further research is needed to explore approaches to involving and standardising Patient and Public Involvement in the development of clinical standards.