Respiratory morbidity in late preterm infants.

BACKGROUND: Late preterm delivery (74% of all preterm births) increases the incidence of respiratory pathology, namely respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN) and the need of ventilator support when compared to term delivery. The aim is to evaluate the respiratory morbimortality in late preterm infants and the risk factors associated with RDS and TTN.

METHODS: Descriptive retrospective study of all newborns of 34+0 to 36+6 weeks of gestational age, born at our center between September 1, 2012 and August 31, 2015. Those with major malformations, chromosomopathies, hydrops fetalis and congenital TORCH infection were excluded.

RESULTS: A total of 498 newborns were studied, 44 (8.83%) of them with either RDS or TTN. Respiratory morbidity was significantly associated with lower gestational age, male gender, caesarean section, exposure to peripartum antibiotics, overweighed and nulliparous mothers. RDS newborns had a significantly higher need for resuscitation, endotracheal intubation, oxygen therapy, early invasive ventilation, parenteral nutrition and a longer NICU stay when compared to newborns with TTN. 55% of the patients with RDS had 35+0 to 36+6 weeks of gestational age, moderate or severe RDS and required mechanical ventilation; six needed surfactant. Caesarean section and resuscitation with ETT were independent risk factors for respiratory morbidity.

CONCLUSIONS: Late preterm remain at risk for adverse respiratory outcomes, particularly newborns delivered after 35 weeks, whose mothers are not given ACS and still have considerable morbidity. Growing evidence supports the possibility of extending the management window further into the LPT period. Caesarean section was an independent risk factor for respiratory morbidity and efforts should be undertaken to reduce the procedure rate.