Impact of Smoking during Pregnancy on Peripheral Tissue Oxygenation in Term Neonates

Abstract

Background: Smoking during pregnancy is associated with higher blood pressure in neonates. Objective: To analyze whether smoking during pregnancy has an influence on peripheral tissue oxygenation in healthy term neonates within the first days after delivery. Methods: In a prospective cohort study, 15 healthy term neonates of mothers who had smoked during pregnancy (smoking group) were matched for gestational age, actual weight and postnatal age to 15 healthy term neonates of mothers who had not smoked during pregnancy (non-smoking group). Peripheral oxygenation was measured by near-infrared spectroscopy in combination with the venous occlusion method on the left forearm. Measurements were performed within the first 2 days after delivery. Tissue oxygenation index (TOI), fractional oxygen extraction (FOE), oxygen delivery (DO₂) and oxygen consumption (VO₂) were analyzed. Results: In neonates measured within the first day after delivery, TOI was significantly lower and FOE was significantly higher (63.5 ± 5.5; 0.37 ± 0.04) in the smoking group compared to the non-smoking group (69.2 ± 2.9; 0.30 ± 0.04). DO₂ tended to be lower and VO₂ tended to be higher in the smoking group. In neonates measured on the second day after delivery, no significant differences were observed between the groups. Conclusions: Smoking during pregnancy reduced TOI and increased FOE in otherwise healthy neonates on the first day of life with normalization on the second day of life.