Impact of Asian ethnicity and national origin on infant birth weight.

To investigate the relation between Asian ethnicity/national origin and low birth weight (< 2,500 g), the authors analyzed singleton live births among 50,044 Asian and 221,866 white women who delivered in California during 1992. Ethnic and subgroup differences in prenatal characteristics and birth weight outcomes were found between Asian and white women and between Asian subgroups. In unadjusted comparisons, very low birth weight (500-1,499 g) was more likely among Filipino women and less likely among Chinese women, relative to whites. Moderately low birth weight (1,500-2,499 g) was more likely among Cambodian, Filipino, Indian, Japanese, Laotian, and Thai women and was less likely among Koreans, relative to whites. In multivariate analyses, Filipino women remained at increased risk of both very low and moderately low birth weight, while Cambodian, Indian, and Laotian women had elevated odds of moderately low birth weight. Chinese women were less likely to have very low birth weight infants than were whites. Utilization of prenatal care was also associated with low birth weight. Perinatal outcomes among Asians vary by national origin, and accepted risk factors that were studied only partially explain this variation.