A systematic review of severe morbidity in infants born late preterm

OBJECTIVE: Late-preterm infants (34 weeks 0/7 days-36 weeks 6/7 days' gestation) represent the largest proportion of singleton preterm births. A systematic review was performed to access the short-and/or long-term morbidity of late-preterm infants. STUDY DESIGN: An electronic search was conducted for cohort studies published from January 2000 through July 2010. RESULTS: We identified 22 studies studying 29,375,675 infants. Compared with infants born at term, infants born late preterm were more likely to suffer poorer short-term outcomes such as respiratory distress syndrome (relative risk [RR], 17.3), intraventricular hemorrhage (RR, 4.9), and death <28 days (RR, 5.9). Beyond the neonatal period, late-preterm infants were more likely to die in the first year (RR, 3.7) and to suffer from cerebral palsy (RR, 3.1). CONCLUSION: Although the absolute incidence of neonatal mortality and morbidity in infants born late preterm is low, its incidence is significantly increased as compared with infants born at term.