Influence of immigration on prematurity in the context of a free healthcare system with universal coverage.

We assessed the risk of preterm birth according to the mother's place of origin in the context of a free and universal healthcare system. We analysed 75,292 newborn infants born between 2008-2011 in Alicante (Spain). The outcomes were: 1) very preterm (gestational age ≤ 32 weeks) and 2) moderate-to-late preterm (gestational age 33-37 weeks). Other variables: infant's gender, maternal age and origin. We estimated adjusted odds ratios to analyse the relationship between the outcomes and the other variables. The distribution of the gestational age groups in our sample was: very preterm, 812; moderate-to-late preterm, 5,295; full-term, 69,997. There were no statistically significant differences between the mother's place of origin and the outcomes in this free universal healthcare system, which is experiencing the recent phenomenon of immigration. This equality should be maintained throughout the time the immigrants remain in the country.