16 - Trends in Late Preterm Infants in the Neonatal Intensive Care Unit

Poster Number: 16
Publication Number: 16.337

Chelsea O. Lockyear, Duke University School of Medicine, Durham, NC, United States; Kristi L. Coe, Duke University School of Nursing, Haw River, NC, United States; Rachel G. Greenberg, Duke Clinical Research Institute, Durham, NC, United States; Reese H. Clark, MEDNAX, Myrtle Beach, SC, United States; Samia Aleem, Duke University School of Medicine, Durham, NC, United States

Background: Late preterm births have increased over time, accounting for 7.5% of deliveries in 2019. These infants are at risk for significant morbidities such as hypoglycemia, hyperbilirubinemia, respiratory distress, and feeding difficulties. Late preterm infants are a unique target for study, with opportunities for decreased lengths of stay (LOS) through innovative care.

Objective: Characterize demographics and trends in LOS, morbidities, and mortality in late preterm infants.

Design/Methods: We performed a cohort study of infants born at 34 0/7 – 36 6/7 weeks of gestation between 1999-2018 at Pediatrix Medical Group neonatal intensive care units (NICUs). We excluded infants with major congenital anomalies, outborn infants, or those transferred to a higher level of care. We divided infants into 2 eras (1999-2008 and 2009-2018) based on year of hospital discharge, and evaluated trends in LOS. We used chi-square tests to compare demographics and common morbidities in the eras. Morbidities of interest included use of respiratory support, infections, and other laboratory values.

Results: 307,967 infants from 413 NICUs met the inclusion criteria. The median (25th-75th percentile range) for gestational age (GA), birth weight and LOS were 35 (34 – 36) weeks, 2355 (2070 – 2671) grams, and 11 (8 – 16) days in the entire period, respectively. The percentage of late preterm infants was relatively stable through the study period (Figure 1). Postmenstrual age at discharge increased over time for all GAs (p < 0.001, Table 1). Between the two eras, receipt of antenatal steroids increased from 23 to 34% (p < 0.001), whereas receipt of anti-reflux medications decreased significantly (p < 0.001) (Table 2). While overall use of respiratory support remained consistent between the two eras, there was a significant increase in less invasive ventilation; use of high flow nasal cannula increased from 7 to 14% and non-invasive positive pressure ventilation increased tenfold (0.2 to 2%, p< 0.001, Table 2).Conclusion(s): In this large cohort, late preterm infants experienced significant morbidities with increased postmenstrual age at discharge in the recent era. Antenatal steroid use increased between the two eras, which may account for the rise in number of infants supported with less invasive ventilation. The many complications experienced by the late preterm cohort offer opportunities to decrease hospital stays.
Table 1Demographics by time period, 1999-2018
Table 2Morbidities by time period, 1999-2018