Time at birth and short-term outcomes among extremely preterm infants in Spain: a multicenter cohort study

The first hours after birth entail a window of opportunity to decrease morbidity and mortality among extremely preterm infants. The availability of staff and its tiredness vary depending on the timing and day of the week. We hypothesized that these circumstances may impact neonatal outcomes. We have conducted a multicenter cohort study with data obtained from the Spanish neonatal network database SEN1500, where staff doctors are in the house 24/7. The main study exposure was the time of birth; secondary exposures were cumulative work hours from the medical and nurses' shifts and day of the week. The primary outcome was survival to hospital discharge. Secondary outcomes included common preterm infants' in-hospital complications. Univariate and multivariate analysis adjusting for potential confounders was performed. All extremely preterm infants (N = 8798) born between 2011 and 2019 were eligible; 35.7% of them were admitted during the night shift. No differences were found between day and night births regarding survival or morbidity. No differences were found between weekdays and weekends or when considering cumulative worked hours in the shifts. Infants born during the night shift were more likely to be intubated at birth (OR 1.20, CI95% 1.06-1.37), receive surfactant (OR 1.24, CI95% 1.08-1.44), and having anemia requiring transfusion (OR 1.23, CI 95% 1.08-1.42).Conclusion: the time of birth did not seem to affect mortality and morbidity of extremely preterm infants. What is Known: • The first hours after birth in extremely preterm infants are a very valuable opportunity to decrease mortality and morbidity. • Time and day of birth have long been linked to outcomes in preterm infants, with night shifts and weekends classically having higher rates of mortality and morbidity. What is New: • In this study, no differences were found between day and night births regarding survival or major morbidity. • Infants born during the night shift were more likely to be intubated at birth, receive surfactant and having anemia requiring transfusion.