ABSTRACT
OBJECTIVE: To evaluate the mortality and long-term morbidity rates of extremely low birth weight (ELBW) infants admitted to neonatal intensive care units (NICUs). STUDY DESIGN: This was a longitudinal cohort study of all admissions born between 1983 and 2003 with birth weight ≤ 800 g at a single tertiary NICU. Trends in survival and neurodevelopmental outcome rates at school entry in four 5-year epochs were analyzed. RESULTS: Of 917 admissions, 552 survived to NICU discharge, with significantly increasing survival rates from 46% in epoch 1 to 71% in epoch 4 (P < .0001). Although the overall impairment rate of 30% did not change, the pattern of impairments did. Cognitive (P = .017) and hearing (P = .014) impairment rates increased. Visual impairment rates decreased (P = .042), with a trend toward decreasing cerebral palsy from 20% to 12% (P = .061). CONCLUSIONS: Improved survival of low birth weight preterm infants has been associated with different types of neurodevelopmental impairments, including increased cognitive impairment rates.
Subject(s)
Developmental Disabilities/epidemiology , Infant, Extremely Low Birth Weight , Age Factors , Female , Follow-Up Studies , Humans , Infant, Newborn , Male , Survival RateABSTRACT
OBJECTIVE: Little is known about the developmental trajectory of cortisol levels in preterm infants after hospital discharge. STUDY DESIGN: In a cohort of 225 infants (gestational age at birth <33 weeks) basal salivary cortisol levels were compared in infants born at extremely low gestational age (ELGA, 23-28 weeks), very low gestational age (29-32 weeks), and term (37-42 weeks) at 3, 6, 8, and 18 months corrected age (CA). Infants with major neurosensory or motor impairment were excluded. RESULTS: At 3 months CA, salivary cortisol levels were lower in both preterm groups compared with the term infants (P = .003). Conversely, at 8 and 18 months CA, the ELGA infants had significantly higher basal cortisol levels than the very low gestational age and term infants (P = .016 and P = .006, respectively). CONCLUSIONS: In ELGA infants, the shift from low basal cortisol levels at 3 months to significantly high levels at 8 and 18 months CA suggests long-term "resetting" of endocrine stress systems. Multiple factors may contribute to these higher cortisol levels in the ELGA infants, including physiological immaturity at birth, cumulative stress related to multiple procedures, and mechanical ventilation during lengthy hospitalization. Prolonged elevation of the cortisol "set-point" may have negative implications for neurodevelopment and later health.