A systematic review of severe morbidity in infants born late preterm

Am J Obstet Gynecol. 2011 Oct;205(4):374.e1-9. doi: 10.1016/j.ajog.2011.07.015. Epub 2011 Jul 20.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Cohort Studies
  • Gestational Age
  • Humans
  • Infant, Newborn
  • Infant, Premature, Diseases / epidemiology*
  • Severity of Illness Index