BDNF and infection: In ADHD mothers, the BDNF gene’s percentage of methylation correlates negatively with newborn birth weight (tau di Kendall = −0.387 and p = 0.008) and positively with threatened miscarriage (tau di Kendall = 0.409 and p = 0.017) and infections (tau di Kendall = 0.356 and p = 0.038) during pregnancy (Table 3).