title: Etiological aspects of ectopic pregnancy in nulliparous women.
mesh_terms: D000328:Adult; D004715:Endometriosis / Q000150:complications; D005187:Fallopian Tubes / Q000002:abnormalities; D005260:Female; D006801:Humans; D010298:Parity; D000292:Pelvic Inflammatory Disease / Q000150:complications; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000209:etiology*; D012189:Retrospective Studies