Trends in morbidities of late preterm infants in the neonatal intensive care unit

To characterize demographics and trends in length of stay (LOS), morbidities, and mortality in late preterm infants.

Cohort study of infants born between 34 ^0/7 and 36 ^6/7 weeks gestation between 1999 and 2018 without major congenital anomalies at Pediatrix Medical Group neonatal intensive care units (NICUs).

307,967 infants from 410 NICUs met inclusion criteria. The median (25^th-75^th percentile) LOS was 11 (8-16) days in the entire period. Postmenstrual age (PMA) at discharge increased during the cohort for all gestational ages (p < 0.001). There was a decrease in invasive ventilation, receipt of phototherapy, and reflux medications observed (p < 0.001).

In this large cohort, given 20 years of time for medical advancement, there was no significant improvement in the LOS of late preterm infants. All infants had an increased PMA at discharge, despite multiple practice changes that were observed.