A potential explanation for the finding that the risk of AF was highest for the combination of preterm birth and LGA may be that maternal medical conditions, such as diabetes and/or obesity during pregnancy lead to preterm birth, and together induce lasting physiological alterations, such as insulin resistance, vascular endothelial dysfunction, and cardiac damage, that lead to AF. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.