Background: Maternal obesity during pregnancy is associated with poorer cardiovascular health (CVH) in children. A strategy to improve CVH in children could be to address preconception maternal obesity by means of a lifestyle intervention. We determined if a preconception lifestyle intervention in women with obesity improved offspring’s CVH, assessed by magnetic resonance imaging (MRI). Methods: We invited children born to women who participated in a randomised controlled trial assessing the effect of a preconception lifestyle intervention in women with obesity. We assessed cardiac structure, function and geometric shape, pulse wave velocity and abdominal fat tissue by MRI. Results: We included 49 of 243 (20.2%) eligible children, 24 girls ...