Racial/Ethnic and nativity differences in birth outcomes among mothers in New York City: the role of social ties and social support.

Immigrants have lower rates of low birth weight (LBW) and to some extent preterm birth (PTB), than their US-born counterparts. This pattern has been termed the 'immigrant health paradox'. Social ties and support are one proposed explanation for this phenomenon. We examined the contribution of social ties and social support to LBW and PTB by race/ethnicity and nativity among women in New York City (NYC). The NYC Pregnancy Risk Assessment Monitoring System survey (2004-2007) data, linked with the selected items from birth certificates, were used to examine LBW and PTB by race/ethnicity and nativity status and the role of social ties and social support to adverse birth outcomes using bivariate and multivariable analyses. SUDAAN software was used to adjust for complex survey design and sampling weights. US- and foreign-born Blacks had significantly increased odds of PTB [adjusted odds ratio (AOR) = 2.43, 95 % CI 1.56, 3.77 and AOR = 2.6, 95 % CI 1.66, 4.24, respectively] compared to US-born Whites. Odds of PTB among foreign-born Other Latinas, Island-born Puerto Ricans' and foreign-born Asians' were not significantly different from US-born Whites, while odds of PTB for foreign-born Whites were significantly lower (AOR = 0.47, 95 % CI 0.26, 0.84). US and foreign-born Blacks' odds of LBW were 2.5 fold that of US-born Whites. Fewer social ties were associated with 32-39 % lower odds of PTB. Lower social support was associated with decreased odds of LBW (AOR 0.69, 95 % CI 0.50, 0.96). We found stronger evidence of the immigrant health paradox across racial/ethnic groups for PTB than for LBW. Results also point to the importance of accurately assessing social ties and social support during pregnancy and to considering the potential downside of social ties.