Abstract: Objective To explore the effect of antenatal corticosteroids on respiratory diseases in late-preterm infants. Methods The clinical data of late-preterm infants delivered from January 2016 to June 2020 and their mothers were retrospectively analyzed. According to prenatal application of dexamethasone, the infants were divided into hormone group and control group, and the incidence of respiratory diseases in late preterm infants with different gestational ages was compared. Multivariate logistic regression analysis was used to analyze the risk factors of post-natal respiratory diseases in late preterm infants. Results In the gestational age group of 36 ~ 36+ 6 weeks, the rate of cesarean section in the hormone group was higher than that in the control group. In the gestational age group of 35 ~ 35+ 6 weeks and 36 ~ 36+ 6 weeks, the rate of premature rupture of membranes in the hormone group was lower than that in the control group, and the differences were statistically significant (P

Key words: respiratory diseases; antenatal corticosteroids; late-preterm infant