Race and neonatal respiratory morbidity in the late preterm period: Race and late term respiratory morbidity.

BACKGROUND: Prematurity is one of the leading causes of perinatal morbidity and mortality. Some studies suggest that respiratory disease may differ by race in early preterm infants. However, the role of race in late term neonatal morbidity is not yet established.

OBJECTIVE: The objective of our study was to determine whether neonatal respiratory morbidity differs by race in neonates born late preterm.

STUDY DESIGN: This is a secondary analysis of a randomized trial of women at high risk for late preterm delivery (Antenatal Late Preterm Steroids, ALPS). Our study was limited to women with non-anomalous, singleton gestations delivering between 34+0 to 36+6 weeks. Women were categorized into four groups by race: Black, White, Asian, or other/mixed. Primary outcome was a neonatal composite of treatment in the first 72 hours (CPAP or high flow nasal cannula >2 hours, oxygen >4 hours, ECMO or mechanical ventilation) or stillbirth or neonatal death before 72 hours. Secondary outcomes include severe respiratory morbidity (SRM, the primary outcome extending CPAP or high-flow nasal cannula to >12 continuous hours and oxygen to at least 24 continuous hours), respiratory distress syndrome, transient tachypnea of the newborn, apnea, neonatal intensive care unit admission, bronchopulmonary dysplasia and surfactant administration. The primary and secondary outcomes were assessed in the active (steroid) and placebo groups separately. We fit a logistic regression model to adjust for confounders related to respiratory morbidity.

RESULTS: Of a total of 2,331 included women, 26.9% (n= 627) were Black/African American, 57.1% White (n=1333), 3.56% Asian (n=83) and 12.36% (n=288) were other/mixed. In the placebo group the rate of the primary outcome was significantly higher in Whites (18.6%) and Asians (22.8%) compared to the African American/Black group (12.3%) (p=0.03). Adjusting for confounders, the primary outcome was not significant between the groups. The primary predictor for respiratory morbidity was a prior pregnancy with neonatal respiratory morbidity. Findings were similar in the steroid group, but severe respiratory morbidity was less common in Black infants compared with White infants, (aOR 0.45, 95%CI 0.24, 0.83). However, a prior pregnancy with neonatal respiratory complications was no longer associated with respiratory morbidity after receipt of betamethasone.

CONCLUSION: Late term respiratory morbidity was similar between racial groups. While history of pregnancy with previous neonatal respiratory disease is the strongest risk factor for recurrence, this risk factor is mitigated by receipt of steroids.