Background Pregnancy after all types of solid organ transplantation (SOT) is possible, although these have higher risk of pregnancy complications for mother and child, such as preeclampsia and preterm birth. Thus, the development of the unborn child seems to be affected by the transplant and its consequences such as the immunosuppressive medication use. Worldwide data regarding follow-up after birth is scarce. The very limited existing data existing only in young children are reassuring. However, the investigators hypothesize that there are health risks for the children. Given the side effects of the immunosuppressive medication on patients and limited knowledge from animal studies, the investigators particularly expect cardiovascular effects such as hypertension and kidney damage. These develop over a long time-period and lead late to symptoms. Aims Aim of this study is to gain more insight into the overall health of offspring born after SOT. Primary aim is to assess the cardiovascular health and the presence of kidney disease, and compare these with reference values from the general population or birth cohorts. Secondary aims are the immunological status including the microbiome of the child given the maternal immunosuppressive medication use, and the overall development of the offspring, including qualitative research regarding the quality of life. Third aim is to assess if there are differences in health between offspring born to mothers with a kidney, liver, pancreas (including pancreas islet), heart and lung transplantation (KTx, LiTx, PTx, HTx, LuTx resp.). The investigators also want to establish a biobank for later follow-up research. Study design This will be a cross-sectional monocenter cohort study. All offspring ≥16 years of age born after KTx or LiTx and all offspring born at any age after PTx, HTx and LuTx in the Netherlands will be eligible for inclusion. The investigators estimate that there will be about 150(-220) participants. Before the study visit, participants will be asked to complete a questionnaire. Participants will be invited for a one-time study visit consisting of physical tests (including ultrasound of the kidneys and a 24-hour ambulatory blood pressure measurement) and biological sample (urine, blood and feces) collection, including sample collection for biobanking. Information about the growth and development of the offspring and, if present, diseases and medication use will be collected from the medical files of the general practitioner and pharmacy (LSP) and from data from the youth healthcare check-ups. As a control group pseudoanonymized data from the Lifelines cohort will be used. Deliverables To the best of our knowledge, this will be the first study worldwide that will gather and analyze detailed information about the cardiovascular, kidney and immunological health at a later age (≥16 years) in the offspring born to mothers after KTx, LiTx, PTx, HTx and LuTx. This information will be important for the preconceptional counseling of families with a pregnancy wish after transplantation and thereby contribute to the health of women with a SOT. Next to that, find adverse effects of the pregnancy after transplantation on the offspring are found, the investigators expect there will be modifiable factors and/or early screening/interventions that can reduce these risks and thereby contribute to the health of the offspring.