Every week counts in fetal respiratory development

Being born even a few weeks early increases the risk for respiratory distress syndrome (RDS) and other respiratory morbidities, according to findings from a recent multicenter study conducted by the Consortium on Safe Labor. The study is perhaps the largest to date on the subject using recent medical record data and controlling for multiple factors that influence neonatal respiratory outcomes, including maternal medical condition, labor and mode of delivery, and birth weight.

Researchers calculated that of almost 20,000 late preterm births (between 34 and 37 weeks' gestation), 7,055 (36.5%) were admitted to a neonatal intensive care unit and 2,032 had respiratory compromise compared with 11,980 (7.2%) and 1,874, respectively, of 165,993 term infants.

The incidence of RDS was 10.5% for infants born at 34 weeks' gestation versus 0.3% at 38 weeks. Similarly, incidences of transient tachypnea of the newborn, pneumonia, and respiratory failure for those born at 34 weeks versus at 38 weeks were, respectively, 6.4% versus 0.4%, 1.5% versus 0.1%, and 1.6% versus 0.2%. Similar patterns existed for standard and oscillatory ventilator support.

Similar patterns were noted for transient tachypnea of the newborn, pneumonia, and respiratory failure.

Consortium for Safe Labor; Hibbard JU, Wilkins I, Sun L, et al. Respiratory morbidity in late preterm births. JAMA. 2010;304(4):419-425.