Do time of birth, unit volume, and staff seniority affect neonatal outcome in deliveries at ≥34+0 weeks of gestation?

OBJECTIVE: weeks of gestation. DESIGN: Population-based prospective cohort study. SETTING: Ten public hospitals in the Austrian province of Styria. SAMPLE: A total of 87 065 neonates delivered in the period 2004-2015. METHODS: Based on short-term outcome data, generalised linear mixed models were used to calculate the risk for adverse and severely adverse neonatal outcomes according to time of birth, unit volume, and staff seniority. MAIN OUTCOME MEASURES: Neonatal composite adverse and severely adverse outcome measures. RESULTS: The odds ratio for severely adverse events during the night-time (22:01-07:29 hours) compared with the daytime (07:30-15:00 hours) was 1.35 (95% confidence interval, 95% CI 1.13-1.61). There were no significant differences in neonatal outcome comparing weekdays and weekends, and comparing office hours and shifts. Units with 500-1000 deliveries per year had the lowest risk for adverse events. Adverse and severely adverse neonatal outcomes were least common for midwife-guided deliveries, and became more frequent with the level of experience of the doctors attending the delivery. With increasing pregnancy risks, senior staff attending delivery and delivering in a tertiary centre reduce the odds ratio for adverse events. CONCLUSIONS: Different times of delivery were associated with increased adverse neonatal outcomes. The management of uncomplicated deliveries by less experienced staff showed no negative impact on perinatal outcome. In contrast, riskier pregnancies delivered by senior staff in a tertiary centre favour a better outcome. Achieving a better balance in the total number of labour ward staff during the day and the night appears to be a greater priority than increasing the continuous presence of senior obstetrical staff on the labour ward during the out-of-hours period. TWEETABLE ABSTRACT: Deliveries during night time lead to a greater number of neonates experiencing severely adverse events.