title: Demonstration of gonadotropin during the second half of the cycle in women using intrauterine contraception.
abstract: A highly sensitive pregnancy test based upon partial purification of urinary gonadotropins by Sephadex gel filtration and concentration of the gonadotropin-containing fraction by lyophilization has been developed. Values over 100 I.U. per liter after Day 22 are considered to indicate conception. They are verified by radioimmunoassay (RIA) of the beta-subunit of human chorionic gonadotropin (HCG) in plasma. Urine samples from users of intrauterine contraception were examined at random. Among samples collected after Day 21, 14 contained more than 100 I.U. per liter. In three of these cases, RIA of the beta-subunit HCG in plasma was employed and verified the results. The results support the hypothesis that intrauterine contraception interferes with implantation and establishment of pregnancy but not with fertilization and blastocyst formation.
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood / Q000652:urine; D005260:Female; D006062:Gonadotropins / Q000652:urine*; D006801:Humans; D007434:Intrauterine Devices; D007986:Luteinizing Hormone / Q000652:urine; D008598:Menstruation; D011247:Pregnancy; D011863:Radioimmunoassay
chemical_list: D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D007986:Luteinizing Hormone