BDNF and Cognitive impairment: Previous studies within the ELGAN cohort have highlighted the associations between differential methylation in placenta of hypothalamic-pituitary-adrenal (HPA) axis genes, such as nuclear receptor subfamily group 3CMember 1 (NR3C1), FK506 binding protein 5 (FKPB5), and brain-derived neurotrophic Factor (BDNF), and cognitive impairment in the offspring (Meakin et al., 2018).