title: Correspondence (letter to the editor): methodological problems.
authors.forename: Wolf
authors.initials: W
authors.lastname: Kirschner
authors.forename: Klaus
authors.initials: K
authors.lastname: Friese
authors.forename: Albrecht
authors.initials: A
authors.lastname: Scheffler
mesh_terms: D059026:Diagnostic Self Evaluation; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D047928:Premature Birth / Q000517:prevention & control*; D016585:Vaginosis, Bacterial / Q000175:diagnosis* / Q000517:prevention & control*