陣痛発来から児娩出に要する所要時間の検討 : 助産所2施設における42年間の記録から  [in Japanese] Trend of average duration of labor in pregnant Japanese women : Long-range 42-year study at two midwifery centers  [in Japanese]

分娩所用時間は,今から100年以上も以前に出版された文献に報告されているものと,現行のものとの間に大差を認めない。しかし,その間,妊婦の生活は大きく変化しており,日常生活の変化が,女性の生理的な分娩進行に与える影響は大きいと考えられるが,分娩所要時間に関する報告は乏しい。本研究は,現行の分娩所要時間の妥当性を検討することを目的に,助産院で出産した妊娠37週以後の産婦に自然陣痛が発来した2,742例をデータとして収集した。さらにデータを3群(1群;1961〜1974年,2群;1975〜1984年,3群;1985〜2003年)に分類した結果,時代が推移するごとに,所要時間は短縮していた。そして3群(1985〜2003)の陣痛発釆から児娩出に要した平均所要時間は,初産婦14時間38分,経産婦7時間59分であった。

The average time required for normal childbirth among Japanese women has generally been considered to have remained the same for over 100 years since first reported in 1903. Since we anticipated that considerable changes in daily lifestyles of pregnant women would have some influence on the physiological process of the childbirth, we investigated the duration of labor in a total of 2,756 pregnant women who had natural childbirths in the 37th week or later of gestation at two midwifery centers. These cases spanned a period of 42 years (1961〜2003), and we grouped them into three separate periods. As results, the respective average duration of labor of primiparas and multiparas in Group 1 (1961〜1974) was 19.35hr and 9.55hr, in Group 2 (1975〜1984) was 16.08hr and 8.17hr, and in Group 3 (1985〜2003) was 14.38hr and 7.59hr, a significant reduction of labor duration over the course of years (p<0.01). Although the reported durations of labor in text books are nearly unchanged over the past 100 years (i. e., 15hr for primipara and 7hr for multipara in 1902, versus 12〜16hr for primipara and 5〜8hr for multipara in 2003), we presume the increase and decrease of the hours in the past suggest nutritional changes before / after World War II, which influenced obesity, as opposed to recent education on weight-control in both pregnant women and fetuses for smooth delivery.