title: Problems in the comparison of clinical performance of IUDs.
authors.forename: S
authors.initials: S
authors.lastname: Jarvela
mesh_terms: D000367:Age Factors; D003267:Contraception; D005069:Evaluation Studies as Topic; D005193:Family Planning Services; D005387:Finland; D005500:Follow-Up Studies; D007434:Intrauterine Devices; D010298:Parity; D012015:Reference Standards; D012106:Research; D012107:Research Design
keywords: Age Factors; Contraception; Contraceptive Methods; Data Adjustment; Evaluation; Family Planning; Finland; Follow-up Studies; Iud; Parity; Research Methodology; Standardization; Studies