BACKGROUND: Although prevalence of low birth weight has increased in the last 3 decades in Japan, no studies in Japanese women have investigated whether birth weight is associated with the risk of pregnancy complications, such as pregnancy-induced hypertension (PIH) and gestational diabetes mellitus (GDM).
METHODS: We used data from the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT), a population-based cohort study in Japan that launched in 2011. In the main analysis, we included 46,365 women who had been pregnant at least once, for whom information on birth weight and events during their pregnancy was obtained using a self-administered questionnaire. Women were divided into five categories according to their birth weight, and the relationship between birth weight and risk of PIH and GDM was examined using multilevel logistic regression analyses with place of residence as a random effect.
RESULTS: Compared to women born with birth weight of 3,000-3,999 grams, the risk of PIH was significantly higher among women born <1,500 grams (adjusted odd ratio [aOR] 1.60; 95% confidence interval [CI], 1.17-2.21), 1,500-2,499 grams (aOR 1.16; 95% CI, 1.03-1.30), and 2,500-2,999 grams (aOR 1.13; 95% CI, 1.04-1.22). The risk of GDM was significantly higher among women born 1,500-2,499 grams (aOR 1.20; 95% CI, 1.02-1.42), albeit non-significant association among women in other birthweight categories.
CONCLUSIONS: We observed an increased risk of PIH among women born with lower birth weight albeit non-significant increased risk of GDM among Japanese women.