Switching pills.
D003276:Contraceptives, Oral / Q000009:adverse effects*; D004967:Estrogens / Q000009:adverse effects*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011372:Progestins
D003276:Contraceptives, Oral; D004967:Estrogens; D011372:Progestins