Letter: Vitamin A, pregnancy, and oral contraceptives.
D000014:Abnormalities, Drug-Induced; D003276:Contraceptives, Oral / Q000009:adverse effects / Q000494:pharmacology*; D005260:Female; D006801:Humans; D011247:Pregnancy; D013997:Time Factors; D014801:Vitamin A / Q000009:adverse effects / Q000097:blood*
D003276:Contraceptives, Oral; D014801:Vitamin A