Contents The effects of glucocorticoids on both foetal canine lung and endogenous serum cortisol concentration have not been clearly delineated. Therefore, we aimed to investigate whether maternal corticosteroid treatment can alter maternal and neonatal cortisol profile and improve neonatal vitality. We allocated six bitches of different breeds and their neonates into two groups: control group (CONT) – maternal administration of saline solution at 55 days post‐ovulation (n = 3); and betamethasone group (BETA) – administration of a single dose of 0.5 mg/kg betamethasone (Celestone Soluspan®) at 55 days post‐ovulation (n = 3). Caesarean sections were scheduled for day 63 after ovulation. However, BETA group dams showed precocious signs of labour, and c‐sections were performed at 58 days post‐ovulation. Maternal and neonatal evaluations were performed periodically between betamethasone administration and birth, respectively. Neonates from both groups presented unsatisfactory (<5) Apgar score at birth. However, in spite of an earlier improvement on vitality found on CONT group and the premature delivery on BETA group, both groups showed acceptable Apgar score 120 min after birth. Neonatal cortisol concentrations were higher on CONT group compared to BETA group at birth. In addition, a gradual decrease on maternal cortisol concentrations was observed in the BETA group from treatment until parturition. These findings suggest that despite the down‐regulation on the hypothalamic‐pituitary‐adrenal axis and the induction of premature delivery, betamethasone treatment was able to provide similar vitality when compared to the untreated neonates born at term.