Letter: Vitamin A, pregnancy, and oral contraceptives.
D002338:Carotenoids / Q000097:blood; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008722:Methods; D011247:Pregnancy; D014801:Vitamin A / Q000097:blood*
D003276:Contraceptives, Oral; D014801:Vitamin A; D002338:Carotenoids