Context: For more than 30 years, guidelines for perinatal regionalization have recommended that very low-birth-weight (VLBW) infants be born at highly specialized hospitals, most commonly designated as level III hospitals. Despite these recommendations, some regions continue to have large percentages of VLBW infants born in lower-level hospitals.
Objective: To evaluate published data on associations between hospital level at birth and neonatal or predischarge mortality for VLBW and very preterm (VPT) infants.
Data sources: Systematic search of published literature (1976-May 2010) in MEDLINE, CINAHL, EMBASE, and PubMed databases and manual searches of reference lists.
Study selection and data extraction: Forty-one publications met a priori inclusion criteria (randomized controlled trial, cohort, and case-control studies measuring neonatal or predischarge mortality among live-born infants < or = 1500 g or < or = 32 weeks' gestation delivered at a level III vs lower-level facility). Paired reviewers independently assessed publications for inclusion and extracted data using standardized forms. Discrepancies were decided by a third reviewer. Publications were reviewed for quality by 3 authors based on 2 content areas: adjustment for confounding and description of hospital levels. We calculated weighted, combined odds ratios (ORs) using a random-effects model and comparative unadjusted pooled mortality rates.
Data synthesis: We observed increased odds of death for VLBW infants (38% vs 23%; adjusted OR, 1.62; 95% confidence interval [CI], 1.44-1.83) and VPT infants (15% vs 17%; adjusted OR, 1.55; 95% CI, 1.21-1.98) born outside of level III hospitals. Consistent results were obtained when restricted to higher-quality evidence (mortality in VLBW infants, 36% vs 21%; adjusted OR, 1.60; 95% CI, 1.33-1.92 and in VPT infants, 7% vs 12%; adjusted OR, 1.42; 95% CI, 1.06-1.88) and infants weighing less than 1000 g (59% vs 32%; adjusted OR, 1.80; 95% CI, 1.31-2.46). No significant differences were found through subgroup analysis of study characteristics. Meta-regression by year of publication did not reveal a change over time (slope, 0.00; P = .87).
Conclusion: For VLBW and VPT infants, birth outside of a level III hospital is significantly associated with increased likelihood of neonatal or predischarge death.