Objective: To report the effect of antenatal corticosteroids (ANS) on mortality, intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD) and the duration of ventilation according to sex in extremely preterm infants.
Methods: All extremely preterm infants admitted to any neonatal unit in England between 2014 and 2019.
Results: Eleven thousand seven hundred and fourteen infants (54% male) were included with a median (IQR) gestational age of 26 + 1 (24 + 6 - 27 + 1) weeks, birth weight of 809 (670 - 960) grams and birth weight z-score of -0.38 (-0.88 to 0.07). ANS were administered in 10,449 infants (89%); equally in males and females. Infants who received ANS compared to those who did not, had a lower mortality before discharge (18.7 versus 32.3%, p < .001), a lower incidence of IVH grade III-IV (14.5 versus 25.5%, p < .001) and a shorter median (IQR) duration of mechanical ventilation [10 (3-27) versus 13 (5-31) days, p < .001]. Female compared to male infants had a lower mortality (18.7 versus 21.7%, p < .001), a lower incidence of IVH grade III-IV (10.9 versus 13.9%, p < .001), a lower incidence of bronchopulmonary dysplasia (61.6 versus 68.2%, p= <.001) and a shorter median (IQR) duration of mechanical ventilation days [9 (3-26) versus 13 (4-29) days, p= <.001]. In females, the risk of dying before discharge from hospital was greater in those who did not receive ANS (odds ratio (OR) 1.81, 95% CI 1.35-2.44) than in those who did (OR 0.55, 95% CI 0.41-0.74). In males the risk of dying was also greater in those that did not receive ANS (OR 1.36, 95% CI 1.03-1.77) compared to those who did (OR 0.74, 95% CI 0.57-0.96).
Conclusion: Antenatal corticosteroids had a greater beneficial effect in female compared to male extremely prematurely born infants in reducing death before discharge.
Keywords: BPD; IVH; Prematurely born infants; antenatal corticosteroids; mortality.