Yet fatigue, reduced out-of-hours PI3K activation resources and more limited access to senior obstetric support are factors that prevail when performing OVDs at night. Several studies have reported higher levels of morbidity and mortality in relation to operative interventions performed outside routine working hours.13–15 Few studies to date have addressed OVD outcomes in relation to time of birth. The purpose of this study was to evaluate maternal and neonatal outcomes associated with OVDs performed by day and at night. The findings will contribute to the debate on safe obstetric care and workforce planning and have important implications for all surgical specialties where emergency care is required at

night. Methods The Coombe Women and Infants University Hospital, Dublin is a consultant-led university teaching hospital with between

8500 and 9000 deliveries annually. The OVD rate in 2012 was 15% (30% in nulliparae) and the CS rate was 27%. Maternal and neonatal care is provided by an interdisciplinary team of midwives, obstetricians, anaesthetists and paediatricians. Routine care on the labour ward is provided by midwives with medical rounds taking place twice daily at 08:00 and 17:00. Obstetricians in training are allocated to the labour ward and receive direct or indirect supervision depending on their level of experience and expertise. Consultant support is readily available between the hours of 08:00 and 20:00 when consultants are usually on-site. Consultants are likely to be off-site between the hours of 20:00 and 08:00 and provide an on-call service to the labour ward. In addition, consultants attend the delivery of private patients (approximately 15% of the overall caseload),16 and any consultant who is on the premises at the time of an emergency will provide immediate assistance. At night, there are either one or two obstetric trainees resident on-call, depending on experience, and one on-call consultant who is non-resident. Labour ward protocols for OVDs are in accordance with the RCOG Guidelines.3 The on-call consultant is expected to attend for all second stage CSs, all OVDs conducted in an operating theatre (complex procedures usually involving

a malposition or mid-cavity station) and whenever the obstetric trainee (or senior midwife) requests support. Cohort All women who required an OVD were eligible for inclusion in the Carfilzomib study if they were nulliparous (no previous delivery ≥24 weeks of gestation), with a live singleton pregnancy and a cephalic presentation at term (gestation of ≥37 weeks). A team of research midwives and obstetricians identified participants from daily labour ward records and the electronic maternity database. The recruitment period took place from 1 February 2013 to 19 November 2013. We recorded detailed data on each mother and baby up until the time of hospital discharge. The study was non-interventional and required no direct patient contact, and no request for follow-up information.