title: Socioeconomic variations in female fertility impairment: a study in a cohort of Portuguese mothers.
abstract: OBJECTIVE
  This study aimed to assess the association of socioeconomic conditions with female fertility impairment among women who delivered a live birth.
  
  
  METHODS
  Cross-sectional analysis.
  
  
  METHODS
  Population-based birth cohort (Generation XXI) assembled in 2005/2006 from five public maternity units in Porto Metropolitan Region, Northern Portugal.
  
  
  METHODS
  7472 women aged 18 or more with spontaneous conception and no male diagnosis of infertility were recruited and interviewed immediately after birth with structured questionnaires.
  Maternal education, occupation and income were recorded as proxy indicators of social conditions.
  
  
  RESULTS
  Impaired female fertility, defined as women who had unsuccessfully tried to conceive for over a year.
  
  
  METHODS
  Multivariate logistic regression models were fitted to estimate the association between each socioeconomic indicator and impaired female fertility, stratified by previous pregnancy experience and adjusted for age, pregnancy planning and behavioural characteristics.
  
  
  RESULTS
  Among primigravidae, 7.7% (95% CI 6.8% to 8.6%) presented impaired fertility and the prevalence was 9.6% (95% CI 8.7% to 10.6%) in multigravidae. In crude analysis, we found women with impaired fertility to be older, less educated, more likely to have planned the current pregnancy and to be overweight/obese; they had similar levels of income or occupation. In multivariate models, a significant independent association between educational level and female fertility impairment remained among primigravidae (OR (95% CI) vs ≤6 schooling years: 7-9: 0.85 (0.54 to 1.34); 10-12: 0.34 (0.21 to 0.54); >12: 0.24 (0.14 to 0.40), ptrend<0.001) but not in multigravidae.
  
  
  CONCLUSIONS
  This study shows that education might be important in understanding female fertility impairment, particularly among first-time pregnant women. It also points out that the association is not totally explained by other sociodemographic and lifestyle characteristics that have been previously found to be important to disclose this relation.
authors.affiliation: Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal.
authors.forename: Sofia
authors.initials: S
authors.lastname: Correia
authors.forename: Teresa
authors.initials: T
authors.lastname: Rodrigues
authors.forename: Henrique
authors.initials: H
authors.lastname: Barros
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000453:epidemiology*; D050498:Live Birth; D011174:Portugal / Q000453:epidemiology; D012959:Socioeconomic Factors
keywords: Epidemiology; Social Medicine