Increased adverse perinatal outcome of hospital delivery at night JP de Graaf, a ACJ Ravelli, b GHA Visser, c C Hukkelhoven, d WH Tong, a GJ Bonsel, e EAP Steegers a a Division of Obstetrics and Prenatal Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, b Department of Medical Informatics, Academic Medical Centre, University of Amsterdam, Amsterdam, c Department of Obstetrics and Gynaecology, University Medical Centre Utrecht, Utrecht, d The Netherlands Perinatal Registry, Utrecht and e Department of Health Policy and Management, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands Correspondence: Dr EAP Steegers, Division of Obstetrics and Prenatal Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Centre Rotterdam, PO Box 2040, 3000 CA, Rotterdam, the Netherlands. Email e.a.p.steegers@erasmusmc.nl Accepted 14 April 2010. Published Online 25 May 2010. Objective To determine whether delivery in the evening or at night and some organisational features of maternity units are related to perinatal adverse outcome. Design A 7-year national registry-based cohort study. Setting All 99 Dutch hospitals. Population From nontertiary hospitals (n = 88), 655 961 singleton deliveries from 32 gestational weeks onwards, and, from tertiary centres (n = 10), 108 445 singleton deliveries from 22 gestational weeks onwards. Methods Multiple logistic regression analysis of national perinatal registration data over the period 2000–2006. In addition, multilevel analysis was applied to investigate whether the effects of time of delivery and other variables systematically vary across different hospitals. Main outcome measures Delivery-related perinatal mortality (intrapartum or early neonatal mortality) and combined delivery-related perinatal adverse outcome (any of the following: intrapartum or early neonatal mortality, 5-minute Apgar score below 7, or admission to neonatal intensive care). Results After case mix adjustment, relative to daytime, increased perinatal mortality was found in nontertiary hospitals during the evening (OR, 1.32; 95% CI, 1.15–1.52) and at night (OR, 1.47; 95% CI, 1.28–1.69) and, in tertiary centres, at night only (OR, 1.20; 95% CI, 1.06–1.37). Similar significant effects were observed using the combined perinatal adverse outcome measure. Multilevel analysis was unsuccessful; extending the initial analysis with nominal hospital effects and hospital–delivery time interaction effects confirmed the significant effect of night in nontertiary hospitals, whereas other organisational effects (nontertiary, tertiary) were taken up by the hospital terms. Conclusion Hospital deliveries at night are associated with increased perinatal mortality and adverse perinatal outcome. The time of delivery and other organisational features representing experience (seniority of staff, volume) explain hospital-to-hospital variation. Keywords Adverse perinatal outcome, early neonatal mortality, intrapartum mortality, organisation of maternity units, seniority of staff, timing of hospital delivery, volume of deliveries. Please cite this paper as: de Graaf J, Ravelli A, Visser G, Hukkelhoven C, Tong W, Bonsel G, Steegers E. Increased adverse perinatal outcome of hospital delivery at night. BJOG 2010;117:1098–1107. Introduction Over 70% of Dutch women deliver at hospital. 1 At the time of delivery, care is focused on risk surveillance and intervention, if indicated, including assisted delivery and neonatal intensive care. This requires the ready availability of experienced professionals and supportive facilities. High- care facilities and multiple expert competences cannot be represented at all hospitals on a 24-hour/7-day basis, however, because of issues of cost-effectiveness. In the Netherlands, 9% of deliveries are scheduled, but the major- ity of nonscheduled deliveries occur around the clock, with a biphasic pattern, including a peak – under natural condi- tions – in the early morning. 2 Heterogeneity with respect to facility and personnel cov- erage around the clock is the rule rather than the exception for most clinical care, even in surgery and intensive care. Studies have shown moderate to strong associations between patient outcomes and organisational features, both with regard to the volume of care and care that is daytime dependent, such as physician staffing and the immediate availability of anaesthesiological services. 3–7 1098 ª 2010 The Authors Journal compilation ª RCOG 2010 BJOG An International Journal of Obstetrics and Gynaecology DOI: 10.1111/j.1471-0528.2010.02611.x www.bjog.org General obstetrics