Rationale and design of a prospective cohort study and biobank of the offspring born to mothers with a solid organ transplant: protocol for the TransplantLines Next Generation study.

introductionSuccessful pregnancies with healthy newborns have been reported after all types of solid organ transplantation (SOT). Limited data in young children suggest similar development and health compared with the general population. However, fetal development may be influenced by factors such as immunosuppressive medication and the increased incidence of pregnancy complications, and forthcoming health problems may only become apparent later in the life of the offspring. To allow for better investigation of the long-term health of offspring born after SOT, we designed the Transplantlines Next Generation biobank and cohort study. This study will be the first with detailed data on overall health status at later age in offspring born to mothers after kidney, liver, pancreas (including pancreas islet), heart and lung transplantation (KTx, LiTx, PTx, HTx and LuTx, respectively). METHODS AND ANALYSIS: Transplantlines Next Generation is a descriptive, prospective cohort study and biobank. It includes offspring aged≥16 years born after KTx or LiTx. Because of the scarcity of pregnancies after (solo) PTx, HTx and LuTx worldwide, and as a consequence the lack of information about these pregnancies, we want to include all offspring, at any age, born after (solo) PTx, HTx and/or LuTx in the Netherlands. Participants will attend a one-time visit for questionnaires, physical tests (for participants≥16 years including kidney ultrasound and 24-hour ambulatory blood pressure) and biological sample collection (urine, blood, faeces) for participants≥16 years of age for biobanking. Reference values and values from existing birth cohorts will serve as controls. Primary endpoints are cardiovascular and kidney health, assessed through growth charts, physical tests (eg, body composition, blood pressure, kidney ultrasound) and metabolic and kidney function biomarkers. Secondary aims include immunological status, microbiome analysis, quality of life and overall development. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the local medical ethical committee; the Institutional Review Board METc UMC Groningen (METc 2023/610). The study will be conducted according to the Declaration of Helsinki and in accordance with the Medical Research Involving Human Subjects Act and other guidelines, regulations and Acts including the General Data Protection Regulation (GDPR). All participants will give written informed consent upon enrolment. TransplantLines Next Generation is designed to deliver pioneering insights into the health of offspring born after SOT. This knowledge will help optimise care and available information for families with a pregnancy wish after SOT and provide a rationale for future studies. The results of this study are planned to be submitted for publication in relevant peer-reviewed journals and will be presented at national and international conferences. TRIAL REGISTRATION NUMBER: NCT07291258.