title: Differences between women who begin pill use before and after first intercourse: Ontario, Canada.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data; D002170:Canada; D003075:Coitus; D003276:Contraceptives, Oral / Q000008:administration & dosage*; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006306:Health Surveys; D006801:Humans; D012725:Sexual Behavior
chemical_list: D003276:Contraceptives, Oral