title: How do levonorgestrel-only emergency contraceptive pills prevent pregnancy? Some considerations.
abstract: Controversial opinions exist about the possible mechanisms throughout emergency contraception prevents pregnancy. Recently, the International Federation of Gynaecology and Obstetrics and the International Consortium for Emergency Contraception released a Joint Statement declaring that 'inhibition or delay of ovulation should be their primary and possibly only mechanism of action'. They still added that 'Review of the evidence suggests that LNG-ECPs cannot prevent implantation'. Concerning levonorgestrel-only emergency contraceptive pills effects on ovulation, the Statement based on seven reference papers which considered a total of only 142 patients, divided into still different subgroups. Basing on their same references we got quite different conclusions.
authors.affiliation: Department of Gynecological and Human Reproductive Sciences, University of Padua, Italy. bruno.mozzanega@unipd.it
authors.forename: Bruno
authors.initials: B
authors.lastname: Mozzanega
authors.forename: Erich
authors.initials: E
authors.lastname: Cosmi
mesh_terms: D044363:Contraception, Postcoital / Q000379:methods*; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000494:pharmacology; D003281:Contraceptives, Postcoital / Q000008:administration & dosage / Q000494:pharmacology; D010064:Embryo Implantation / Q000187:drug effects; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000008:administration & dosage* / Q000494:pharmacology*; D010060:Ovulation / Q000187:drug effects; D011247:Pregnancy / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects; D013607:Tablets
chemical_list: D003271:Contraceptive Agents, Female; D003281:Contraceptives, Postcoital; D013607:Tablets; D016912:Levonorgestrel