450: A systematic review for severe morbidity in infants born late preterm

Abstract

Late preterm infants (34 0/7 to 36 6/7 weeks gestation) are the largest proportion of singleton preterm births. They are usually considered to be functionally and developmentally as mature as term newborns, and therefore of little concern for medical research. As a consequence, the morbidity among late preterm infants has not been assessed systematically. We therefore performed a systematic review on the subject. We performed an electronic search of PubMed, Medline, Embase and Cochrane trials databases (from January 2000 to June 2010) for cohort studies that reported on short-term and/or long-term outcomes of infants born late preterm. When the study also reported on the outcome of infants born at term (≥ 37 weeks), we compared outcomes by calculating odds ratios (OR) with 95% confidence intervals (95% CI). We identified 33 articles. Compared to infants born at term, infants born late preterm were more likely to have a 5 minute Apgar score <7 (OR 4.1, 95% CI 3.8 to 4.4), more likely to need mechanical ventilation (OR 2.8, 95% CI 2.6 to 3.1), to suffer from transient tachypnea (OR 6.7, 95% CI 6 to 7.4), respiratory distress syndrome (OR 4.7, 95% CI 4.2 to 5.3), hypothermia (OR 13, 95% CI 5.6 to 31), hypoglycaemia (OR 6.5, 95% CI 5.6 to 7.5), jaundice requiring phototherapy (OR 3.8, 95% 3.5 to 4.1), sepsis work-up (OR 1.9, 95% CI 1.8 to 2.0), convulsions (OR 1.5, 95% CI 0.94 to 2.4), intraventricular haemorrhages (OR 3.6, 95% CI 2.8 to 4.7), necrotizing enterocolitis (OR 9.2, 95% CI 3.9 to 21) or death before 28 days (OR 9.3, 95% CI 8.8 to 9.4). Regarding long-term outcomes, late preterm infants were more likely to die in the first year (OR 3.3, 95% CI 3.2 to 3.3), to suffer from cerebral palsy (OR 3.0, 95% CI 2.5 to 3.5), and less likely to complete high school (OR 0.83, 95% CI 0.81 to 0.84). Although the absolute incidence of neonatal mortality and morbidity in infants born late preterm is low, its incidence is significantly increased as compared to term delivery.