mode of action

Last reviewed 03/2021

  • like other hormonal contraceptives, levonorgestrel might work by altering tubal motility, interfering with fertilisation, disrupting ovulation or via inhibition of the implantation of the fertilised ovum (1)
  • no specific mode of action for levonorgestrel has been defined for its role in post-coital contraception (2)


  1. Glasier A. Emergency postoital contraception. NEJM 1997; 337: 1058-64.
  2. Drug and Therapeutics Bulletin 2000; 38 (10): 75-77.