Prospective study of women using different methods of contraception.
D000022:Abortion, Spontaneous / Q000209:etiology; D003273:Contraceptive Devices; D003276:Contraceptives, Oral; D005260:Female; D006801:Humans; D007434:Intrauterine Devices / Q000009:adverse effects; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000209:etiology; D011446:Prospective Studies
D003276:Contraceptives, Oral