title: Reappraising the relationship between maternal age and postpartum depression according to the evolutionary theory: Empirical evidence from a survey in primary health services.
abstract: BACKGROUND
  Postpartum depression (PPD) is a widespread worldwide phenomenon, but its etiology remains unclear. This study reappraised how evolutionary theory could explain PPD as an adaptation through investigating the relationship between maternal age and PPD, and if this relationship is modified according to the number of children at home.
  
  
  METHODS
  A cross-sectional study carried out in five primary health care units included 811 participants randomly selected among mothers of children up to five postpartum months in Rio de Janeiro, Brazil. Postpartum depression was defined by scores above 11 on Edinburgh Postnatal Depression Scale (EPDS), and statistical analysis was based on multivariate logistic regression models.
  
  
  RESULTS
  One hundred and ninety-seven (24.3%, CI 95% 21.3-27.2) participants were classified as PPD positives. Maternal age was significantly associated to PPD (OR=0.96, p-value=0.019) independently of socioeconomic and reproductive characteristics, conjugal status or substance consumption by the couple. Thus, for each additional year, a reduction of 4% in the chance of developing PPD could be anticipated, effect which was not modified by the number of children at home (p-value=0.602).
  
  
  CONCLUSIONS
  Information on social support was not included in this analysis since its relationship with maternal mental health would be better evaluated in a prospective fashion.
  
  
  CONCLUSIONS
  These findings suggest that adaptive mechanisms shaped through human generations persist contributing to the development of PPD in contemporary societies. According to this evolutionary approach, as maternal age advances the reproductive potential diminishes and, consequently, mothers are less prone to develop PPD and reduce investment in new offspring.
authors: Institute of Social Medicine, State University of Rio de Janeiro (UERJ), Rio de Janeiro, Brazil.
authors: Marcela N
authors: MN
authors: Bottino
authors: Paulo
authors: P
authors: Nadanovsky
authors: Claudia L
authors: CL
authors: Moraes
authors: Michael E
authors: ME
authors: Reichenheim
authors: Gustavo
authors: G
authors: Lobato
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000453:epidemiology; D001938:Brazil / Q000453:epidemiology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D019052:Depression, Postpartum / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D011320:Primary Health Care / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012923:Social Class; D012944:Social Support; D013179:Spouse Abuse / Q000706:statistics & numerical data; D019966:Substance-Related Disorders / Q000453:epidemiology; D014932:Women's Health Services / Q000706:statistics & numerical data*; D055815:Young Adult