Birth weight among singletons born to foreign-born mothers in Taiwan: A population-based birth register study

Abstract

Background: We compared the birth weight of newborns born to foreign-born mothers (FBMs) and Taiwan-born mothers (TBMs), using data from the 2005-2006 Taiwan Birth Registry of singleton live births. Methods: The Wilcox-Russell method, data restriction, and multiple linear regression were used to analyze the data. The rates of low birth weight (<2500 g) with 95% confidence intervals were computed for TBMs, and for each of the nationalities of FBMs. Results: The mean birth weight of newborns of FBMs was 3157 g, which was higher than that of newborns of TBMs (3109 g). On analysis using the Wilcox-Russell method, both the rate and residual proportion of low-birthweight (LBW) births were lower among newborns of FBMs (4.1% and 1.1%, respectively) than among newborns of TBMs (5.9% and 1.7%, respectively). After adjusting for sex, mode of delivery, maternal age, smoking status, predisposing maternal risk factors, and condition during pregnancy, the newborns of FBMs weighed 72.9 g (95% CI, 68.8 g to 77.0 g) more than the newborns of TBMs. When data were restricted to mothers without any adverse conditions and adjusted for maternal age, the differences in birth weight between the 2 groups remained unchanged. The rates of LBW deliveries among FBMs in Taiwan were significantly lower than those in their respective countries of origin. Conclusions: In Taiwan, newborns of FBMs had a higher birth weight than those of TBMs, even after accounting for potential confounding factors, and had lower rates of LBW deliveries than did mothers in their respective countries of origin. © 2009 by the Japan Epidemiological Association.