title: Sri Lanka pill and vitamin trial produces important data.
mesh_terms: D001208:Asia; D003267:Contraception; D003270:Contraceptive Agents; D003271:Contraceptive Agents, Female; D003276:Contraceptives, Oral; D003277:Contraceptives, Oral, Combined; D003278:Contraceptives, Oral, Hormonal; D003906:Developing Countries; D004311:Double-Blind Method; D005193:Family Planning Services; D005500:Follow-Up Studies; D008656:Mestranol; D009640:Norethindrone; D009641:Norethynodrel; D012106:Research; D013188:Sri Lanka
chemical_list: D003270:Contraceptive Agents; D003271:Contraceptive Agents, Female; D003276:Contraceptives, Oral; D003277:Contraceptives, Oral, Combined; D003278:Contraceptives, Oral, Hormonal; D009641:Norethynodrel; D008656:Mestranol; D009640:Norethindrone
keywords: Asia; Clinical Research; Comparative Studies; Contraception; Contraception Continuation; Contraceptive Agents; Contraceptive Agents, Estrogen; Contraceptive Agents, Female; Contraceptive Agents, Progestin; Contraceptive Methods--side effects; Developing Countries; Double-blind Studies; Family Planning; Follow-up Studies; Mestranol; Norethindrone; Norethynodrel; Oral Contraceptives, Combined; Oral Contraceptives--side effects; Research Methodology; Southern Asia; Sri Lanka; Studies