title: Socioeconomic position early in adolescence and mode of delivery later in life: findings from a Portuguese birth cohort.
abstract: OBJECTIVE
  This study assessed the influence of socioeconomic position at 12 years of age (SEP-12) on the variability in cesarean rates later in life.
  
  
  METHODS
  As part of the Portuguese Generation XXI birth cohort we evaluated 7358 women with a singleton pregnancy who delivered at five Portuguese public hospitals serving the region of Porto (April/2005-September/2006). Based on the twelve items that described socioeconomic circumstances at age 12, a latent class analysis was used to classify women's SEP-12 as high, intermediate and low. Multiple Poisson regression was used to estimate adjusted risk ratio (RR) and respective 95% confidence interval (95% CI).
  
  
  RESULTS
  The cesarean rates in high, intermediate and low SEP-12 were, respectively, 40.9%, 37.5% and 40.5% (p = 0.100) among primiparous women; 14.2%, 11.6% and 15.5% (p = 0.04) among multiparous women with no previous cesarean and 78.6%, 72.2% and 70.0% (p = 0.08) among women with a previous cesarean. A low to moderate association between SEP-12 and cesarean rates was observed among multiparous women with a previous cesarean, illustrating that women from higher SEP-12 were more likely to have a surgical delivery (RR = 1.12;95%CI:1.01-1.24 comparing high with low SEP-12 and RR = 1.03:95%CI:0.94-1.14 comparing intermediate with low SEP-12) not explained by potential mediating factors. No such association was found either in primiparous or in multiparous women without a previous cesarean.
  
  
  CONCLUSIONS
  The association between SEP-12 and cesarean rates suggests the effect of past socioeconomic context on the decision concerning the mode of delivery, but only among women who experienced a previous cesarean. Accordingly, it appears that early-life socioeconomic circumstances drive cesarean rates but the effect can be modified by lived experiences concerning childbirth.
authors: Institute of Public Health, University of Porto, Porto, Portugal; Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal; Polytechnic Institute of Bragança, Bragança, Portugal.
authors: Cristina
authors: C
authors: Teixeira
authors: Institute of Public Health, University of Porto, Porto, Portugal; Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal.
authors: Susana
authors: S
authors: Silva
authors: Institute of Public Health, University of Porto, Porto, Portugal; Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal.
authors: Milton
authors: M
authors: Severo
authors: Institute of Public Health, University of Porto, Porto, Portugal; Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal.
authors: Henrique
authors: H
authors: Barros
mesh_terms: D000293:Adolescent; D000328:Adult; D001294:Attitude to Health; D002585:Cesarean Section / Q000523:psychology* / Q000706:statistics & numerical data*; D002648:Child; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000523:psychology* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D010298:Parity; D011159:Population Surveillance; D011174:Portugal; D011247:Pregnancy; D012307:Risk Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D055815:Young Adult