Anesthesia in early childhood is associated with adverse neurodevelopmental outcome; however, it is not known if age at exposure affects the risk of adverse outcome. Our objective was to evaluate the association of the number and timing of anesthetic exposures for surgery with cognitive outcome in a cohort of premature newborns.A cohort study of exposure to anesthesia for surgery in premature newborns (<33 wk gestation) prospectively evaluated with neonatal magnetic resonance imaging (MRI) and neurodevelopmental testing at 3-6 y was employed. Exposure to anesthesia for surgery was classified as before term-equivalent age (TEA, <42 wk postmenstrual age) or after (≥42 wk). Multivariate regression was performed to analyze the association of composite IQ scores with the number of surgeries before and after TEA.Among 137 newborns, 25 (18.2%) had one surgery before TEA and 18 (13.1%) had ≥2 surgeries. Two or more surgeries before TEA were associated with significantly reduced composite IQ scores at 4.6 ± 0.6 y after adjusting for gestational age and illness severity. Neither the number of surgeries after TEA nor sedation for MRI was associated with cognitive outcome.More than one surgery prior to TEA is independently associated with impaired cognitive performance in premature newborns
