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Recent trend of increase in proportion of low birthweight infants in Japan

H Ohmi1, K Hirooka, A Hata

  • 1Health and Disease Prevention Division, Department of Health and Welfare, Hokkaido Government, N3-W6, Chuo-ku, Sapporo, Hokkaido 060-8588, Japan. hiroki.oomi@pref.hokkaido.jp

International Journal of Epidemiology
|February 1, 2002
PubMed

Insights

Since the 1970s, rising smoking rates and declining body mass index in young Japanese women, particularly those in their thirties, have driven an increase in low birthweight babies. This trend highlights critical public health concerns for maternal and infant health.

Area of Science:

  • Reproductive Health
  • Public Health
  • Pediatrics

Background:

  • The incidence of low birthweight babies (LBW) in Japan declined until the 1970s but has since shown a consistent increase.
  • The underlying causes for this rise in LBW have not been extensively investigated.

Purpose of the Study:

  • To analyze the trends in birthweight and identify key contributing factors to the rise in low birthweight babies since the 1970s in Japan.

Main Methods:

  • Utilized vital statistics, national nutritional surveys, and smoking prevalence data.
  • Analyzed trends in birthweight, maternal smoking, and pre-pregnancy body mass index.

Main Results:

  • Increased term LBW, linked to intrauterine growth retardation, is a primary driver of the overall rise.
  • Maternal smoking prevalence increased in the 1970s (thirties) and 1960s (twenties).
  • Decreased maternal body mass index (BMI) trends mirrored smoking prevalence, starting in the 1970s (thirties) and 1960s (twenties).
  • The proportion of deliveries to mothers in their thirties increased significantly, more than threefold since the late 1970s.

Conclusions:

  • Increased smoking prevalence and decreased BMI among young women, especially those in their thirties, are identified as major factors contributing to the rise in LBW babies since the 1970s.
  • These demographic and lifestyle changes represent significant public health challenges impacting infant birthweight.
Abstract

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