title: IUDs and ectopic pregnancy.
authors.forename: I
authors.initials: I
authors.lastname: Sivin
mesh_terms: D016022:Case-Control Studies; D003271:Contraceptive Agents, Female / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007435:Intrauterine Devices, Copper / Q000009:adverse effects*; D007436:Intrauterine Devices, Medicated / Q000009:adverse effects*; D016912:Levonorgestrel / Q000009:adverse effects*; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000453:epidemiology / Q000209:etiology*; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors
chemical_list: D003271:Contraceptive Agents, Female; D016912:Levonorgestrel