Matsuda S, Hiroshige Y, Furuta M, Doi T, Sone T, Kahyo H
Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Hum Biol. 1995 Aug;67(4):641-56.
Seasonal variation of mean birth weight (MBW), mean gestational period (MGP), and MBW at 40 weeks of gestation (MBW40) in the 15 different prefectures of Japan were analyzed using vital statistics from 1974 to 1983. MBW generally shows a bimodal pattern with two peaks in spring and autumn and two troughs in summer and winter. Seasonality exhibits a general geographic trend: The autumn peak loses its height and the spring peak increases its amplitude as one moves from north to south. This trend suggests that environmental factors are associated with the creation of seasonality in MBW. For MGP the pattern is relatively unimodal with a deep trough in winter; however, a late summer small dip is observed in most cases. According to an analysis of coincidence between the two time series (MBW and MGP) and correlation analysis, the seasonal variation in birth weight basically depends on the gestational period. For MBW40, which represents the fetal growth rate, the seasonality shows a pattern similar to that of MBW. A statistically significant coincidence and a correlation are observed between the time series of MBW and MBW40. These results suggest that the two processes of fetal growth (gestational period and fetal growth rate) are associated with the creation of seasonality in MBW.
利用1974年至1983年的人口动态统计数据，分析了日本15个不同辖区平均出生体重（MBW）、平均妊娠期（MGP）以及妊娠40周时的平均出生体重（MBW40）的季节性变化。MBW通常呈现双峰模式，在春季和秋季有两个峰值，在夏季和冬季有两个低谷。季节性呈现出一般的地理趋势：随着从北向南移动，秋季峰值变低，春季峰值幅度增大。这种趋势表明环境因素与MBW季节性的形成有关。对于MGP，模式相对单峰，冬季有一个深谷；然而，在大多数情况下，夏末会出现一个小低谷。根据对两个时间序列（MBW和MGP）的重合分析和相关性分析，出生体重的季节性变化基本上取决于妊娠期。对于代表胎儿生长速率的MBW40，季节性呈现出与MBW相似的模式。在MBW和MBW40的时间序列之间观察到具有统计学意义的重合和相关性。这些结果表明，胎儿生长的两个过程（妊娠期和胎儿生长速率）与MBW季节性的形成有关。
