Nighttime birth raises mortality risk

Nighttime delivery increases risk

Higher mortality rates among inborn infants admitted to neonatal intensive-care units at night. Lee SK; Lee DS, Andrews WL, et al. J Pediatr 2003: 143;592-597

“Risk-adjusted analysis showed that the added risk incurred by nighttime admission was equivalent to 29 excess deaths per 1000 infants. In-house availability of experienced physicians at night substantially lowered the mortality risk.” (emphasis ours: mortality risk was reduced by 40%)

  • 5192 infants 24-32 weeks gestation
  • Born in 17 Canadian NICUs over a 22 month period
  • Compared risk-adjusted early neonatal deaths (within 7 days of NICU admission) in infants admitted during the day and at night
  • Birth weight, gestational age, and 5-minute APGAR scores were similar for the 2 cohorts, as were other factors.
  • 60% of admissions happened overnight

Increased risk at night

Timing of birth and infant and early neonatal mortality in Sweden 1973-95: longitudinal birth register study. Luo AC, Karlberg J, BMJ (323) 1-5, 8 Dec 2001

“Infants born during the night have a greater risk of infant and early neonatal mortality…than those born during the day…the problem is much more serious for preterm infants…”

  • Objective to assess the time of birth on infant mortality and early neonatal mortality in full term and preterm births
  • Post-hoc analysis of data from Swedish birth register 1973-1995
  • 2,102,324 births without congenital malformation

Measured absolute and relative risk of infant mortality and early neonatal mortality

Coverage by experienced physicians at night helps reduce risk

Low 5-minute Apgar score: a population-based register study of 1 million term births. Thorngren-Jerneck K, Herbst A. Obstetrics & Gynecology 2001; 98:65-70

“The risk of low Apgar score was higher in infants born during “non-office hours” (5:00 pm-6:59 am) as compared with infants born during office hours (8:30 am-3:59 pm)”

  • Objective to study the influence of obstetric risk factors on low 5-minute Apgar scores
  • 1,028,705 Swedish newborns, from 1988-1997
  • Concluded that several obstetric risk factors were associated with low 5-minute Apgar score in term infants, including maternal smoking, breech delivery, and multiple births, as well as nighttime delivery

Declining Severity Adjusted Mortality: Evidence of Improving Neonatal Intensive Care. Richardson DY, Gray JE, Gortmaker SL, et al. Pediatrics 1998:102;893-9

“Another potential contributor to improved neonatal survival is the escalation to 24-hour attending level coverage”

  • Compared 2 cohorts in the same 2 hospitals 5 years apart (1989-1990 and 1994-1995) of infants <1500 grams
  • NICU mortality declined from 17.1% to 9.5% and total mortality declined from 31.6% to 18.4%
  • One third of the decline is attributable to improved condition on admission; two thirds of the decline is attributable to more effective newborn intensive care