Mortality and pulmonary outcomes of extremely preterm infants exposed to antenatal corticosteroids

Abstract

Background: Antenatal corticosteroids are given primarily to induce fetal lung maturation but results from meta-analyses of randomized controlled trials have not shown mortality or pulmonary benefits for extremely preterm infants although these are the infants most at risk of mortality and pulmonary disease.

Objective: We sought to determine if exposure to antenatal corticosteroids is associated with a lower rate of death and pulmonary morbidities by 36 weeks' postmenstrual age.

Study design: Prospectively collected data on 11,022 infants 22 0/7 to 28 6/7 weeks' gestational age with a birthweight of ≥401 g born from Jan. 1, 2006, through Dec. 31, 2014, were analyzed. The rate of death and the rate of physiologic bronchopulmonary dysplasia by 36 weeks' postmenstrual age were analyzed by level of exposure to antenatal corticosteroids using models adjusted for maternal variables, infant variables, center, and epoch.

Results: Infants exposed to any antenatal corticosteroids had a lower rate of death (2193/9670 [22.7%]) compared to infants without exposure (540/1302 [41.5%]) (adjusted relative risk, 0.71; 95% confidence interval, 0.65-0.76; P < .0001). Infants exposed to a partial course of antenatal corticosteroids also had a lower rate of death (654/2520 [26.0%]) compared to infants without exposure (540/1302 [41.5%]); (adjusted relative risk, 0.77; 95% confidence interval, 0.70-0.85; P < .0001). In an analysis by each week of gestation, infants exposed to a complete course of antenatal corticosteroids had lower mortality before discharge compared to infants without exposure at each week from 23-27 weeks' gestation and infants exposed to a partial course of antenatal corticosteroids had lower mortality at 23, 24, and 26 weeks' gestation. Rates of bronchopulmonary dysplasia in survivors did not differ by antenatal corticosteroid exposure. The rate of death due to respiratory distress syndrome, the rate of surfactant use, and the rate of mechanical ventilation were lower in infants exposed to any antenatal corticosteroids compared to infants without exposure.

Conclusion: Among infants 22-28 weeks' gestational age, any or partial antenatal exposure to corticosteroids compared to no exposure is associated with a lower rate of death while the rate of bronchopulmonary dysplasia in survivors did not differ.

Keywords: antenatal corticosteroids; bronchopulmonary dysplasia; infant; intracranial hemorrhage; mechanical ventilation; morbidity; mortality; necrotizing enterocolitis; neonatal; newborn; patent ductus arteriosus; periventricular leukomalacia; pneumothorax; preterm; pulmonary; pulmonary hemorrhage; respiratory distress syndrome; respiratory support; sepsis; surfactant.

Figure 1

Frequency of exposure to antenatal corticosteroids (ANS) by gestational age and year of birth. The administration of antenatal corticosteroids increased over the study period but remained lower at the lower gestational ages.

Figure 2

Death before discharge of infants 22 to 28 weeks’ gestation by antenatal corticosteroid (ANS) exposure. Infants exposed to a course of antenatal corticosteroids had a lower rate of death before discharge compared to infants who were not exposed to antenatal corticosteroids at each gestational age from 23 to 27 weeks. Infants exposed to a partial course of antenatal corticosteroids had lower mortality at 23, 24, and 26 weeks’ gestation.