title: Stillbirth risk by maternal socio-economic status and country of origin: a population-based observational study in Spain, 2007-08.
abstract: BACKGROUND
  Socio-economic differences are a major determinant of perinatal outcomes. The impact of low socio-economic status on the risk of stillbirth, and the association between socio-economic status and stillbirth by maternal country of origin at a national level in Spain are unknown. We aimed to analyse the effect of maternal socio-economic status on the risk of stillbirth by maternal country of origin in Spain for the years 2007 and 2008.
  
  
  METHODS
  We designed a population-based observational study that included 970,740 live births and 2464 stillbirths from 2007 to 2008. Univariate risk ratios (RRs) of stillbirth were calculated by maternal education, country of origin, age, parity, and gestational age. Adjusted stillbirth RRs were calculated using a generalized linear model with the Poisson family. Then, adjusted attributable risks and aetiological fractions in the population were calculated as measures of impact.
  
  
  RESULTS
  Stillbirth rate ranged from 1.0 to 4.7 deaths per 1000 births. The stillbirth risk among mothers having secondary or lower education was double than that of mothers with a tertiary education with an adjusted RR of 2.13 [95% confidence interval (CI): 1.74-2.60]. African mothers, compared with mothers from Spain, showed an adjusted stillbirth RR of 1.75 (95% CI: 1.54-2.00).
  
  
  CONCLUSIONS
  This study confirms the differences of stillbirth risk by maternal socio-economic status. Regardless of socio-economic status, African mothers had the highest risk of stillbirth. These results point out the necessity to reduce factors related to social and health inequalities in perinatal mortality in Spain, and more specifically, to take into consideration the special vulnerability of African mothers.
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, University of Cape Town, Cape Town, South Africa. miguel.luquefernandez@uct.ac.za
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: Luque-Fernández
authors.forename: Nazir Iftikhar
authors.initials: NI
authors.lastname: Lone
authors.forename: Ignacio
authors.initials: I
authors.lastname: Gutiérrez-Garitano
authors.forename: Aurora
authors.initials: A
authors.lastname: Bueno-Cavanillas
mesh_terms: D000293:Adolescent; D000328:Adult; D004522:Educational Status; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D009035:Mothers; D016017:Odds Ratio; D010298:Parity; D011159:Population Surveillance; D011247:Pregnancy; D044469:Racial Groups / Q000208:ethnology*; D012042:Registries; D012307:Risk Factors; D012923:Social Class; D012959:Socioeconomic Factors; D013030:Spain / Q000453:epidemiology; D050497:Stillbirth / Q000453:epidemiology* / Q000208:ethnology; D055815:Young Adult