title: [Why are babies born at night at increased risk of early neonatal mortality?].
abstract: BACKGROUND
  Increased perinatal and neonatal mortality rates have been previously reported in night-time births compared with births during the day. This effect has been attributed to decreased quality of medical care during the night. However, alternative explanations exist such as decreased birth-weight of night births. The objective of this study was to further investigate this relationship.
  
  
  METHODS
  Data from 590,332 low risk births (singleton births, > or = 2500 g birth-weight, no major congenital anomaly) were obtained from the perinatal birth register of Hesse, Germany, 1990-2000. Outcome was defined as either death during labour or within 7 days of life. Night-time births were defined as births between 9.00 p.m. and 6.59 a.m., otherwise day-time births were assumed. Subgroup analyses and logistic regression analyses were performed to assess whether the excess mortality of night-births might be explained by other factors.
  
  
  RESULTS
  Mortality rates were increased in night-time births (RR = 1.26; 95% CI = 0.94-1.70). This relationship was more pronounced in spontaneous births (RR = 1.58; 95% CI = 0.96-2.61) and emergency cesarean sections (RR = 1.76; 95% CI = 1.10-2.82). Significance persisted after adjusting for numerous potential confounders.
  
  
  CONCLUSIONS
  Our results confirm an increased mortality risk for night-time births which could not be explained by other accessible risk factors. This suggests that the increased risk at night might be attributable to a reduced availability to provide appropriate medical care in delivery units at night.
  
  
  CONCLUSIONS
  As mainly the presence of staff is decreased during the night, introduction of better designed shifts can be expected to reduce neonatal mortality.
authors.affiliation: Klinik für Geburtshilfe und Perinatologie, Zentrum für Gynäkologie und Geburtshilfe, Universität Marburg.
authors.forename: G
authors.initials: G
authors.lastname: Heller
authors.forename: R
authors.initials: R
authors.lastname: Schnell
authors.forename: B
authors.initials: B
authors.lastname: Misselwitz
authors.forename: S
authors.initials: S
authors.lastname: Schmidt
mesh_terms: D002585:Cesarean Section / Q000706:statistics & numerical data; D002940:Circadian Rhythm / Q000502:physiology*; D004630:Emergencies / Q000453:epidemiology; D005260:Female; D005313:Fetal Death / Q000453:epidemiology* / Q000209:etiology; D005858:Germany; D017052:Hospital Mortality; D006801:Humans; D007231:Infant, Newborn; D009551:Night Care / Q000706:statistics & numerical data*; D007744:Obstetric Labor Complications / Q000453:epidemiology; D010561:Personnel Staffing and Scheduling / Q000706:statistics & numerical data; D011247:Pregnancy; D011785:Quality Assurance, Health Care / Q000706:statistics & numerical data; D012044:Regression Analysis; D012306:Risk