[Main household occupation and mean birth weight in Japan 1984]

By using the 1984 vital statistics released on magnet tapes by the Japanese government, we observed in the present study how the mean birth weight (MBW) varies from one group of mothers who fall under the same category of "main household job" to another. In so doing, we compared the MBWs among different job categories in terms of mother's age, baby's sex, and parity. The obtained results are summarized as follows: 1) The MBW of primiparae and male babies was found to be significantly different among the job categories in the age range of 20-39. In the group of multiparae and male babies, however, all the age ranges older that twenty showed significant differences in the MBW among the job categories. In the group of female babies, the significant difference was found in the age range of 20-39 and all the ranges older than twenty for primiparae and multiparae, respectively. 2) The above results were considered to be caused mainly by the low MBW in the category of "other" for primiparae, and by the high MBW in "part-time farming" and the low MBW in "other" for multiparae.