Oral contraceptives and health:  encouraging evidence in large prospective study.
D003267:Contraception; D003276:Contraceptives, Oral; D005193:Family Planning Services; D011446:Prospective Studies; D012107:Research Design
D003276:Contraceptives, Oral
Contraception; Contraceptive Methods; Family Planning; Matched Groups; Oral Contraceptives; Prospective Studies; Research Report