History of respiratory problems in prior infant and respiratory morbidity in subsequent pregnancy

Respiratory distress syndrome (RDS) is a common cause of morbidity in preterm neonates. Late preterm births (34 0/7 to 36 6/7 weeks of gestation) account for three-quarters of preterm births. Delivery in the late preterm period is a well-established risk factor for RDS.¹ Whether history of a neonate with respiratory morbidity at birth relates to respiratory morbidity in a subsequent pregnancy is not well characterized. In this research letter, we have described how maternally reported respiratory morbidity in a neonate in a previous pregnancy is associated with respiratory morbidity in a neonate in a subsequent pregnancy.

This was a secondary analysis of a randomized controlled study of antenatal corticosteroids in the late preterm period (antenatal betamethasone for women at risk for late preterm delivery).² Multiparous patients with a singleton pregnancy were included. The institutional review board at The University of Chicago (approval number IRB 21-0141) deemed this study exempt. Respiratory morbidity of a previous infant was maternally reported in a questionnaire specifying any "respiratory problems at birth" in their live neonates (yes or no). Major respiratory morbidity (MRM) in the current pregnancy was defined as any of the following: continuous positive airway pressure or high-flow nasal cannula for ≥12 hours in the first 72 hours of life, ventilator use in the first 72 hours of life, extracorporeal membrane oxygenation, oxygen requirement of FiO2 of ≥0.3 for ≥24 total hours in the first 72 hours of life, or stillbirth or neonatal death at <72 hours of age. This was abstracted from maternal and neonatal medical records. The presence of any respiratory morbidity (MRM, RDS, or transient tachypnea of the newborn [TTN]) was compared by history of a previous infant with any respiratory morbidity. Chi-square and Wilcoxon rank-sum tests were used for bivariable analyses, and logistic regression was performed to adjust for confounders. The analysis was repeated, stratified by any betamethasone use.

We included 1412 multiparous patients, 195 with a previous infant with maternally reported respiratory morbidity and 1217 without. RDS, MRM, and a composite of RDS, TTN, and apnea were more likely among those who had a sibling with respiratory morbidity, per maternal report (adjusted odds ratio [aOR] of RDS, 2.17 [95% confidence interval (CI), 1.28-3.70]; aOR of MRM, 1.9 [95% CI, 1.20-3.02]; aOR of RDS, TTN, and apnea, 1.85 [95% CI, 1.22-2.70]). When stratified by administration of betamethasone, the risk of MRM was only persistent in those without betamethasone use (aOR, 1.84; 95% CI, 1.00-3.39). Similarly, the risk of RDS and a composite risk of RDS, TTN, and apnea were only persistent in those without betamethasone use (aOR, 2.37 [95% CI, 1.16-4.84]; aOR, 1.82 [95% CI, 1.05-3.17]) Tables 1 and 2.

A maternally reported history of respiratory morbidity in a previous late preterm or term infant was independently associated with respiratory morbidity, including RDS, in a subsequent infant. When stratified by betamethasone use, the risk of respiratory morbidity was only persistent in those neonates without betamethasone exposure during the late preterm period.