TABLE 5.

Infant Mortality Rates by Birth Weight Groups for the United States, Australia, Canada, and the United Kingdom (United States as Reference)

United States 199839Victoria 199941*Canada 199640England and Wales 199826
Crude mortality
 Rate per 1000 births7.14.35.35.5
 RR1.000.610.760.80
 (95% CI)(0.54, 0.69)(0.72, 0.80)(0.77, 0.82)
Birth weight <500 g
 Rate per 1000 births868.2915.5920.6880.7
 RR1.001.051.061.01
 (95% CI)(0.75, 1.47)(0.86, 1.30)(0.86, 1.20)
Birth weight 500–999 g
 Rate per 1000 births316.6336.1357.6404.6
 RR1.001.061.121.24
 (95% CI)(0.82, 1.36)(0.98, 1.29)(1.16, 1.32)
Birth weight 1000–1499 g
 Rate per 1000 births59.949.576.370.1
 RR1.000.831.261.14
 (95% CI)(0.52, 1.32)(1.02, 1.56)(1.03, 1.27)
Birth weight 1500–1999 g
 Rate per 1000 births28.719.330.923.5
 RR1.000.671.070.84
 (95% CI)(0.41, 1.12)(0.86, 1.35)(0.74, 0.95)
Birth weight 2000–2499 g
 Rate per 1000 births12.56.713.010.2
 RR1.000.531.030.84
 (95% CI)(0.33, 0.85)(0.86, 1.25)(0.76, 0.93)
Birth weight >2500 g
 Rate per 1000 births2.61.32.32.1
 RR1.000.490.870.84
 (95% CI)(0.39, 0.61)(0.79, 0.95)(0.80, 0.88)
  • * Data for entire Australia not available, and these data do not include live births <400 g. Australia has a total IMR for 1999 of 5.0, whereas Victoria has IMR of 4.7.

  • P value < .05.

  • P value < .001.