The pill, chlamydia and PID.
D002690:Chlamydia Infections / Q000209:etiology*; D002692:Chlamydia trachomatis; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000209:etiology; D000292:Pelvic Inflammatory Disease / Q000209:etiology*
D003276:Contraceptives, Oral