BACKGROUND AND OBJECTIVE: Entonox is an odorless, tasteless gas and the first anesthesia agent used in obstetrics. To date, no studies have evaluated the effects of Entonox on oxidative stress. This study aimed to investigate the association between infant oxidative stress indices in mothers exposed to Entonox gas during vaginal delivery. 

METHODS: This cohort study was conducted on 120 pregnant women undergoing natural labor. Subjects were divided into two groups of delivery with and without exposure to analgesic Entonox (N=60). After delivery, 5 ml of arterial blood was obtained from the umbilical cords of all infants, and indicators such as malondialdehyde, thiols and total antioxidant capacity were measured and evaluated in each group.

FINDINGS: In this study, there were no significant differences in the indicators of oxidative stress between the study groups. Values obtained in groups with and without Entonox exposure were respectively as follows: total antioxidant capacity (1.33±1.21 vs. 1.59±1.3, p=0.84), thiols (0.363±0.313 vs. 0.238±0.225, p=0.07), lipid peroxidation (4.60±2.76 vs. 5.31±3.19, p=1).