Radiation exposure in extremely low birth weight infants during their neonatal intensive care unit stay.

BACKGROUND Extremely low birth weight (ELBW <1000 g) infants may have increased sensitivity to radiation exposure. Our objective was to estimate the radiation exposure in survivors of ELBW infants during their neonatal intensive care unit (NICU) stay. METHODS In this retrospective cohort study, medical records of all ELBW infants who had been admitted to our NICU between May 1999 and October 2009 were reviewed. The infants' total entrance skin exposure [ESE in micro-Gray (μGy)] was estimated. RESULTS Among 450 survivors, the mean gestational age (GA) was 26.3±2.1 weeks, and the mean birth weight (BW) was 774.2±144.4 g. Infants received a median of 32 (range: 1-159) X-rays, with an estimated ESE of 1471 μGy (range: 28-9264). Total ESE was inversely proportional to GA (r=-0.34; P<0.01), and BW (r=-0.39; P=0.01) and proportional to the severity of illness [score for neonatal acute physiology-perinatal extension (SNAPPE), r=0.39; P=0.01]. In a linear regression analysis, GA, SNAPPE and necrotizing enterocolitis were associated with radiation exposure (ESE) in ELBW infants (r2=0.133; P<0.001). CONCLUSIONS During their NICU stay, ELBW infants were subjected to a significant number of diagnostic X-ray procedures. Our data highlight the need to closely monitor the number of X-ray procedures ordered to ELBW infants to avoid unnecessary radiation exposure.