Socioeconomic Inequalities in Small-for-Gestational-Age Births Before and During the Economic Crisis: An Ecologic Study of Trends in 13 Spanish Cities

Economic recessions can increase socioeconomic inequalities in health. The objective of this study was to analyze socioeconomic inequalities in small-for-gestational-age (SGA) births before and during the Spanish economic crisis. We conducted an ecological study of trends based on 2 periods before the crisis (1999–2003 and 2004–2008) and another during the crisis (2009–2013). The study population was Spanish women resident in 13 cities who had given birth during 1999–2013. The prevalence of SGA was calculated for each census tract. A hierarchical Bayesian model was used to obtain the prevalence ratio (PR) and 95% credible intervals (CI). We analyzed the association between SGA and socioeconomic deprivation in each period for each city and for 3 age groups. The PR was above 1 and statistically significant for all 3 time periods in most of the 13 cities. The differences in PR between periods were only statistically significant for Madrid (PR = 1.56, 95% CI 1.48–1.65 for 1999–2003; PR = 1.28, 95% CI 1.19–1.38 for 2004–2008) and Barcelona (PR = 0.99, 95% CI 0.87–1.12 for 2004–2008; PR = 1.20, 95% CI 1.05–1.36 for 2009–2013). Socioeconomic inequalities in SGA births in small areas (census tracts) of most Spanish cities studied remained stable before and during the economic crisis.