title: A study of four antigon models and factors in the use-effectiveness of the IUD.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007433:Intrauterine Device Expulsion / Q000009:adverse effects; D007434:Intrauterine Devices / Q000009:adverse effects; D010298:Parity; D014592:Uterine Hemorrhage / Q000209:etiology