title: Natural family planning effectiveness: evaluating published reports.
abstract: OBJECTIVE
  To equip the reader with the tools necessary to evaluate studies of natural family planning (NFP) effectiveness found in the literature and to make recommendations for future NFP effectiveness studies.
  
  
  METHODS
  Current standards to evaluate contraceptive method effectiveness are reviewed. A framework for evaluating reports on NFP is presented.
  
  
  RESULTS
  Most NFP studies found in the literature are flawed in design and do not calculate pregnancy rates correctly. The results from the few well-designed studies are presented.
  
  
  CONCLUSIONS
  Many factors influence NFP effectiveness, and these factors must be considered when evaluating published studies and designing future studies.
authors.affiliation: Institute for Reproductive Health, Georgetown University, Washington, DC 20007, USA.
authors.forename: V
authors.initials: V
authors.lastname: Lamprecht
authors.forename: J
authors.initials: J
authors.lastname: Trussell
mesh_terms: D003267:Contraception; D005069:Evaluation Studies as Topic; D005193:Family Planning Services; D005260:Female; D006801:Humans; D008297:Male; D012252:Natural Family Planning Methods; D011247:Pregnancy