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Objectives: To determine the prevalence of autism spectrum disorders (ASD) across gestational age, examine the risk of ASD by gestational age controlling for other risk factors, and identify potential risk factors in the neonatal intensive care unit. Study design: A retrospective cohort of infants born at ≥24 weeks between January 1, 2000, and December 31, 2007 at 11 Kaiser Permanente Northern California hospitals (n = 195 021). ASD cases were defined by a diagnosis made at a Kaiser Permanente ASD evaluation center, by a clinical specialist, or by a pediatrician. Cox proportional hazards regression models were used to evaluate the association between gestational age and ASD as well as potential risk factors in the neonatal intensive care unit and ASD. Results: The prevalence of ASD in infants <37 weeks was 1.78% compared with 1.22% in infants born ≥37 weeks (P < .001). Compared with term infants, infants born at 24-26 weeks had an adjusted hazard ratio (HR) for a diagnosis of ASD of 2.7 (95% CI 1.5-5.0). Infants born at 27-33 weeks (adjusted HR 1.4, 95% CI 1.1-1.8) and 34-36 weeks (adjusted HR 1.3, 95% CI 1.1-1.4) were also at increased risk. High frequency ventilation and intracranial hemorrhage were associated with ASD in infants < 34 weeks. Conclusions: ASD was ∼3 times more prevalent in infants <27 weeks compared with term infants. Each week of shorter gestation was associated with an increased risk of ASD. High frequency ventilation and intracranial hemorrhage were associated with ASD among infants <34 weeks. [Copyright &y& Elsevier]

Objective: To estimate the effect of phototherapy and other predictors on the risk of total serum bilirubin (TSB) ≥ 25 mg/dL in infants with a TSB of 17 to 22.9 mg/dL at age ≥ 48 hours. Study design: From a cohort of 285295 infants ≥ 34 weeks gestation and ≥ 2000 g born between 1995 and 2004 in northern California Kaiser hospitals, we identified 17986 with a TSB of 17 to 22.9 mg/dL at age ≥ 48 hours. All infants exhibiting a TSB ≥ 25 mg/dL were selected as cases for the study. Four randomly selected controls were matched to each case based on the difference between their qualifying TSB and the American Academy of Pediatrics'' phototherapy threshold. Results: A total of 62 cases were identified (0.4%). Six of these (10%) received inpatient phototherapy within 8 hours, along with 101 controls (41%) (adjusted odds ratio [AOR] 0.15; 95% confidence interval [CI] 0.06 to 0.40). Cases more often had lower gestational age (AOR 3.24; 95% CI 1.24 to 8.47 for 38 to 39 weeks and AOR = 3.70; 95% CI 0.61 to 22.4 for 34 to 37 weeks compared with ≥ 40-week infants), bruising, (AOR 2.52; 95% CI 1.16 to 5.50), exclusive breast-feeding (AOR 2.09; 95% CI 1.05 to 4.03), and TSB increase of ≥ 6 mg/dL/day (AOR 2.39; 95% CI 1.18 to 4.85). Conclusions: Phototherapy was 85% effective in preventing TSB ≥ 25 mg/dL. The strongest predictors of TSB ≥ 25 mg/dL were gestational age, bruising, family history, and rapid rise in TSB. [Copyright &y& Elsevier]