title: Long-term contraception by steroid releasing implants. VI. Serum concentrations of norethindrone in women bearing a single silastic implant releasing norethindrone acetate.
mesh_terms: D000328:Adult; D001682:Biological Availability; D004343:Drug Implants; D005260:Female; D006801:Humans; D009640:Norethindrone / Q000031:analogs & derivatives / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D004343:Drug Implants; D009640:Norethindrone