title: Use of matched pairs in evaluation of a birth control program.
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D003267:Contraception; D003270:Contraceptive Agents; D003273:Contraceptive Devices; D003276:Contraceptives, Oral; D003710:Demography; D004219:District of Columbia; D005193:Family Planning Services; D005260:Female; D006801:Humans; D011247:Pregnancy; D012959:Socioeconomic Factors
chemical_list: D003270:Contraceptive Agents; D003276:Contraceptives, Oral