Contraceptive implants

Abstract
Norplant contains levonorgestrel, a synthetic progestogen prescribed to millions of women over two decades; 15 preparations are currently licensed for contraception and hormone replacement in Britain. Daily dosages of 75-250 µg occur in combined oral contraceptive pills and 30-75 µg in progestogen only pills. Users achieve peak blood concentrations in excess of 2.5 nmol/l.4 …