PMC

Schematic depiction of the survival analysis (obstetric) model for perinatal death or serious neonatal morbidity. Schematic depiction of survival analysis model for perinatal death or serious neonatal morbidity with censoring at death or birth (whichever occurs earlier). Perinatal death and serious neonatal morbidity are assigned to the point of birth. In the first risk period, there are 16 fetuses at risk of perinatal death or serious neonatal morbidity, 3 births, 1 stillbirth, 1 neonatal death and 1 case of serious neonatal morbidity. In the second risk period, there are 7 fetuses at risk, 6 births, 1 stillbirth and 1 case of severe neonatal morbidity. Under the conventional calculation, with perinatal mortality defined as the number of perinatal deaths within any period divided by the number of total births in that period, the perinatal mortality/morbidity rate is 3/3 in the first risk period and 2/6 in the second. Note increase in denominator and decrease in rate from the first risk period to the second risk period (from 100% to 33%). Under the fetuses at risk formulation, with perinatal mortality defined as the number of perinatal deaths in any period divided by the number of fetuses at risk of perinatal death in that period, the perinatal mortality/morbidity rate is 3/16 in the first risk period and 2/7 in the second risk period. Note decrease in denominator and increase in rate from the first to the second risk period (from 19% to 29%).

Risk of adverse perinatal outcomes by time of day. a Risk of perinatal death by hour of decision making. The risk of perinatal death was significantly higher than average for neonates where the decision to deliver by emergency cesarean section was made at night (20:00–02:00) and significantly lower than average where the decision was made in the morning (08:00–12:00), p < 0.01. b Risk of perinatal death by hour of delivery. The risk of perinatal death was significantly higher than average for neonates delivered at night (24:00–08:00) and significantly lower than average where delivery was in the afternoon (14:00–18:00), p < 0.05. c) Risk of neonatal death by hour of decision making. The risk of neonatal death was significantly higher than average for neonates where the decision to deliver by emergency cesarean section was made at night (24:00–02:00) and significantly lower than average where the decision was made in the morning (06:00–12:00), p < 0.05. d) Risk of neonatal death by hour of delivery. The risk of neonatal death was not significantly higher than average for neonates delivered at night, however, was significantly lower than average where delivery was in the afternoon (13:00–17:00), p < 0.05

Most relevant condition of death in 109 cases of perinatal death in late−/postterm pregnancy with an incidence of > 1%

Estimated excess relative risk (●) of major congenital malformations, perinatal death within 7 days, and perinatal death within 14 days among children of atomic bomb survivors, Hiroshima and Nagasaki, Japan, 1948–1953. Solid lines represent the fitted linear dose-response (see ) for the dose-category–specific (<0.05, 0.05–0.49, 0.50–0.99, or ≥1.00 Gy) excess relative risk. A) Major malformations by paternal dose; B) major malformations by maternal dose; C) 7-day perinatal deaths by paternal dose; D) 7-day perinatal deaths by maternal dose; E) 14-day perinatal deaths by paternal dose; F) 14-day perinatal deaths by maternal dose. Bars, 95% confidence intervals.