Adverse perinatal outcomes associated with respiratory distress syndrome in preterm infants: a retrospective analysis

With the development of perinatal medicine and the continuous improvement of neonatal treatment technology, the birth rate of preterm infants is increasing. Respiratory distress syndrome (RDS) is one of the most prevalent complications with a high mortality rate among preterm infants. It is associated with short and long-term adverse outcomes for newborns, and seriously affects their survival rate and long-term quality of life. The aim of the present study was to investigate the perinatal risk factors for RDS, and the major complications and mortality rate associated with RDS in preterm infants, thereby providing a basis for preventing the occurrence of RDS and improving the prognosis of preterm infants.

A retrospective cohort study was conducted by selecting all preterm infants who were admitted to the Neonatal Intensive Care Unit (NICU) of Qilu Hospital, Shandong University (Qingdao) after obstetric delivery from January 2018 to December of 2021. According to whether preterm infants suffered from RDS, they were divided into RDS group (n = 319) and Non- RDS group (n = 366).

A total of 685 preterm infants were included. In the RDS group, the mothers of preterm infants with RDS were older (P < 0.001) and more of advanced maternal age (≥ 35 years, P < 0.005), tended to have a higher rate of cesarean section (P = 0.033), and were more likely to be complicated with pregnancy diabetes and hypertensive disorders during pregnancy (all P < 0.001). Preterm infants with RDS were more prevalent in males (P = 0.025), with smaller gestational age, lighter weight and a higher risk of asphyxia at birth (all P < 0.001). Preterm infants with RDS after birth had a higher rate of pneumonia, sepsis, hypoxic-ischemic encephalopathy (HIE), bronchopulmonary dysplasia (BPD), and had longer anti-infection times (duration of antimicrobial use) and hospitalization times (all P < 0.001), as well as a higher mortality rate of 6.0%, while none died in Non-RDS group (P < 0.001). Among preterm infants who had died, most of them were males, with a mortality rate 8.5 times higher than that of females. Multivariate logistic regression analysis indicated that gestational diabetes (OR = 2.283, 95% CI 1.483-3.513), hypertensive disorders during pregnancy (OR = 2.201, 95% CI 1.215-3.988), gestational age < 32 weeks (OR = 3.914, 95% CI 2.972-5.155), birth weight < 1500 g (OR = 6.610, 95% CI 2.777-13.735), and asphyxia (OR = 5.239, 95% CI 2.602-10.551) were independent risk factors for the occurrence of RDS in preterm infants. Through further analysis, we found that the incidence rate of asphyxia in preterm infants with RDS who used corticosteroids before delivery was decreased (P = 0.02), while the incidence rate of hyperbilirubinemia was increased (P = 0.004), and the hospitalization time was prolonged (P = 0.043), however the mortality rate was not significantly different between the two groups (P > 0.05). With different ventilation modes, the incidence rates of sepsis, BPD and mortality of RDS in preterm infants were significantly increased, and the anti-infection times and the hospitalization time was prolonged in mechanical ventilation group compared with the nasal continuous positive airway pressure ventilation (NCPAP) group (all P < 0.001).

RDS is associated with a higher risk of adverse perinatal outcomes and adverse neonatal outcomes in preterm infants. Reasonable use of corticosteroid before birth and standardized use of ventilators after birth can prevent the occurrence of RDS and improve the prognosis of RDS in preterm infants.