title: A report of the correlation between the pregnancy rates of low estrogen formulations and pill-taking habits of females studied.
mesh_terms: D003276:Contraceptives, Oral / Q000008:administration & dosage*; D003299:Cooperative Behavior; D004967:Estrogens / Q000008:administration & dosage*; D004997:Ethinyl Estradiol / Q000008:administration & dosage; D005260:Female; D006801:Humans; D009640:Norethindrone / Q000008:administration & dosage; D011247:Pregnancy; D011372:Progestins / Q000008:administration & dosage; D013223:Statistics as Topic
chemical_list: D003276:Contraceptives, Oral; D004967:Estrogens; D011372:Progestins; D004997:Ethinyl Estradiol; D009640:Norethindrone