<p><strong>OBJECTIVE: </strong>Examine the effect of off-label surfactant on mortality and morbidity in more mature and larger premature infants diagnosed with respiratory distress syndrome (RDS).</p>

<p><strong>STUDY DESIGN: </strong>Cohort study of premature infants born at 30-36 weeks, birth weight &gt; 2 kg, and a diagnosis of RDS. We compared the odds of mortality and morbidity between infants who were exposed vs unexposed to surfactant. We used a treatment effects model to balance covariates between groups.</p>

<p><strong>RESULTS: </strong>Of 54,964 included infants, 25,278 (46%) were exposed to surfactant. The frequency of mortality and morbidities were higher in the exposed group in unadjusted analyses. Following adjustment with a doubly robust treatment effects model, we found no significant treatment effect of surfactant on mortality or morbidity.</p>

<p><strong>CONCLUSION: </strong>Surfactant exposure is not associated with reduced or increased mortality or morbidity in more mature premature infants with RDS.</p>