Birthweight of children of immigrants by maternal duration of residence in the United States.

A large literature on immigrant health in the U.S. has shown that immigrants tend to be healthier and live longer than both individuals who remain in their countries of origin and natives of their host countries who are of the same race or ethnicity. However, this immigrant health advantage appears to diminish with duration of residence in the U.S. Few studies of the effects of immigrants' exposure to the U.S. have focused on perinatal health. This study used three contemporary national datasets to describe patterns in infant birthweight by maternal duration of residence in the U.S. For both immigrants overall and Hispanic immigrants in particular, rates of low birthweight appeared to decline over the first few years in the U.S. and increase thereafter. This curvilinear association was robust across the three datasets and deviates somewhat from the prevailing notion that immigrant health declines monotonically over time. Additionally, we found no evidence that prenatal substance use increased with duration of residence in the U.S.