title: An epidemiological study on ectopic pregnancy associated with IUD. A matched case-control study.
mesh_terms: D000328:Adult; D002681:China; D005260:Female; D006801:Humans; D007434:Intrauterine Devices / Q000009:adverse effects*; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000453:epidemiology* / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors