title: Letter: Progestogen-only contraception and tubal pregnancies.
mesh_terms: D000328:Adult; D003276:Contraceptives, Oral / Q000009:adverse effects*; D004717:Endometrium / Q000187:drug effects; D005260:Female; D006801:Humans; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000453:epidemiology*; D011372:Progestins / Q000009:adverse effects*
chemical_list: D003276:Contraceptives, Oral; D011372:Progestins