title: Spanish women's attitudes towards post-fertilization effects of birth control methods.
abstract: OBJECTIVE
  Some methods of family planning, such as oral contraceptives, emergency pill or intrauterine device, may occasionally work after fertilization. These effects may be important to some women. We explored Spanish women's attitudes towards contraceptive choices that may have occasional post-fertilization mechanisms of action.
  
  
  METHODS
  Cross-sectional study in a Spanish representative sample of 848 potentially fertile women, aged 18-49. Data were collected using a 30-item questionnaire about family planning. Logistic regression was used to identify variables associated with women's attitudes towards post-fertilization effects.
  
  
  RESULTS
  The majority of women were married, had completed high school and had at least one child. Forty-five percent of women would not consider using a method that may work after fertilization and 57% would not consider using one that may work after implantation. Forty-eight percent of the sample would stop using a method if they learned that it sometimes works after fertilization, increasing to 63% when referring to a method that sometimes works after implantation. Women who believe that human life begins at fertilization, those who believe it is important to distinguish between spontaneous and induced embryo losses and women who report having a religion were less likely to consider the use of a method with some post-fertilization effects.
  
  
  CONCLUSIONS
  The possibility of post-fertilization effects may influence Spanish women's choice of a family planning method. Information about mechanisms of action of birth control methods should be disclosed to women so that they can make informed choices.
authors.affiliation: Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra, Irunlarrea 1, 31008 Pamplona, Navarra, Spain. cldelburgo@unav.es
authors.forename: Cristina
authors.initials: C
authors.lastname: Lopez-del Burgo
authors.forename: Carmen Marina
authors.initials: CM
authors.lastname: Lopez-de Fez
authors.forename: Alfonso
authors.initials: A
authors.lastname: Osorio
authors.forename: José Lopez
authors.initials: JL
authors.lastname: Guzmán
authors.forename: Jokin
authors.initials: J
authors.lastname: de Irala
mesh_terms: D000293:Adolescent; D000328:Adult; D003267:Contraception / Q000379:methods / Q000523:psychology*; D003268:Contraception Behavior / Q000523:psychology*; D003430:Cross-Sectional Studies; D010064:Embryo Implantation; D005193:Family Planning Services; D005260:Female; D005306:Fertilization; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008875:Middle Aged; D013030:Spain