Differences in low-birthweight among documented and undocumented foreign-born and US-born Latinas.

In the USA foreign-born women tend to have fewer low-birthweight births than US-born women from the same ethnicity. This "healthy migrant" effect could be caused by immigration of the fittest or by healthy people being deliberately selected in the immigration process. This study tests these hypotheses by comparing self-reported history of low-birth-weight among foreign-born documented and undocumented Latinas and US-born Latinas. The sample includes 2398 (57.5%) documented foreign-born Latinas, 782 (18.7%) undocumented foreign-born Latinas, and 993 (23.4%) US-born Latinas who initiated prenatal care at MIC-Women's Health Services/MHRA in New York City during 1996-1997. Only women who reported previous live births were included in the sample. Documented foreign-born Latinas were less likely than US-born Latinas to have low-birth-weight babies taking into account parity, age, risk, and education. There were no significant differences between rates of low-birthweight for undocumented foreign-born Latinas and US-born Latinas, or documented foreign-born Latinas. There was, however, a significant trend for rates of low-birthweight to increase from documented foreign-born to undocumented foreign-born to US-born women. This suggests that both official screening and migration of the fittest play a role in lower rates of low-birthweight among foreign-born Latinas compared to US-born Latinas.