IUD users may have higher risk of contracting PID, studies find; pill may have protective effect.
D000293:Adolescent; D000328:Adult; D003276:Contraceptives, Oral / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007434:Intrauterine Devices / Q000009:adverse effects*; D000292:Pelvic Inflammatory Disease / Q000209:etiology / Q000517:prevention & control*; D011247:Pregnancy; D012306:Risk
D003276:Contraceptives, Oral