title: Research on infertility: which definition should we use?
abstract: OBJECTIVE
  Different definitions of infertility are used in clinical practice as well as in epidemiological and demographic research. This study assessed whether the definition makes a difference for estimates of the prevalence and sociodemographic differentials of infertility and whether one definition would be applicable in both research and clinical practice.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Moshi town in northern Tanzania.
  
  
  METHODS
  Community-based sample of 1,125 women, ages 20 to 44 years, in first union.
  
  
  METHODS
  Six definitions of infertility.
  
  
  RESULTS
  Similar levels and sociodemographic characteristics of infertile women were obtained from asking the question "How long have you tried to get pregnant?" and from secondary data collected in a birth history that included date of marriage, date of last birth, current contraceptive use, and whether the woman wants another child.
  
  
  CONCLUSIONS
  The infertility definition made a difference. The World Health Organization definition based on 24 months of trying to get pregnant is recommended as the definition that is useful in clinical practice and research among different disciplines.
authors.affiliation: Department of Population and International Health, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA. ularsen@hsph.harvard.edu
authors.forename: Ulla
authors.initials: U
authors.lastname: Larsen
mesh_terms: D000328:Adult; D003142:Communication; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000208:ethnology* / Q000523:psychology*; D015995:Prevalence; D018456:Reproductive Medicine / Q000706:statistics & numerical data*; D012923:Social Class; D013636:Tanzania / Q000453:epidemiology; D009626:Terminology as Topic; D016387:Women's Health; D014944:World Health Organization