From: Factors associated with birthweight decline in Japan (1980–2004)
variables | units | 1980 | 2004 | ||||||
---|---|---|---|---|---|---|---|---|---|
Preterm (n = 63,821) | non-Preterm (n = 1,505,946) | Preterm (n = 62,935) | non-Preterm (n = 1,047,338) | ||||||
mean | SD | mean | SD | mean | SD | mean | SD | ||
Birthweight | grams | 2396 | 608 | 3223 | 402 | 2191 | 590 | 3063 | 377 |
Gestational age | weeks | 34.27 | 2.46 | 39.47 | 1.23 | 34.28 | 2.73 | 39.11 | 1.17 |
Father age | years of age | 30.70 | 4.78 | 30.31 | 4.19 | 32.49 | 5.95 | 31.63 | 5.59 |
Mother age | years of age | 28.10 | 4.37 | 27.60 | 3.71 | 30.43 | 5.00 | 29.65 | 4.69 |
Delivery number | including present birth | 1.93 | 1.01 | 1.79 | 0.83 | 1.82 | 0.92 | 1.69 | 0.81 |
Multiple gestation | 1 = singleton 2 = multiple birth | 1.03 | 0.18 | 1.01 | 0.09 | 1.22 | 0.41 | 1.01 | 0.10 |
live birth number | 1.89 | 0.98 | 1.78 | 0.82 | 1.80 | 0.91 | 1.68 | 0.80 | |
Neonatal gender | 1 = male 2 = female | 1.43 | 0.50 | 1.49 | 0.50 | 1.44 | 0.50 | 1.49 | 0.50 |