title: Emergency contraception.
abstract: This review summarises the development of emergency contraception (EC) methods, and provides an overview on the currently available options of EC which are effective and safe back-up methods in case of non-use or failure of the regular contraception. The copper intrauterine contraceptive device is currently the most effective method. In most countries, a single dose of levonorgestrel 1.5 mg is the first-line hormonal EC given within 72 h of unprotected intercourse. The oral anti-progestogens such as mifepristone and ulipristal acetate are promising alternatives with better efficacies and a wider treatment window of up to 120 h post coitus, probably resulting from more diverse ancillary mechanisms of actions. Education on EC should be part of any contraceptive counselling. Improving access to EC by providing it over the counter or in advance would not promote its abuse nor encourage risky sexual behaviours, but may further facilitate the timely use so as to achieve the best efficacy.
authors.affiliation: Department of Obstetrics and Gynaecology, The University of Hong Kong, Queen Mary Hospital, Hong Kong; The Family Planning Association of Hong Kong, Hong Kong.
authors.forename: Hang-Wun Raymond
authors.initials: HW
authors.lastname: Li
authors.affiliation: The Family Planning Association of Hong Kong, Hong Kong.
authors.forename: Sue Seen Tsing
authors.initials: SS
authors.lastname: Lo
authors.affiliation: Department of Obstetrics and Gynaecology, The University of Hong Kong, Queen Mary Hospital, Hong Kong; The Family Planning Association of Hong Kong, Hong Kong. Electronic address: pcho@hku.hk.
authors.forename: Pak-Chung
authors.initials: PC
authors.lastname: Ho
mesh_terms: D044363:Contraception, Postcoital / Q000295:instrumentation / Q000379:methods; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D003280:Contraceptives, Oral, Synthetic / Q000008:administration & dosage; D004334:Drug Administration Schedule; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007435:Intrauterine Devices, Copper; D016912:Levonorgestrel / Q000008:administration & dosage*; D015735:Mifepristone / Q000008:administration & dosage; D009649:Norpregnadienes / Q000008:administration & dosage; D013997:Time Factors
chemical_list: D003271:Contraceptive Agents, Female; D003280:Contraceptives, Oral, Synthetic; D009649:Norpregnadienes; D015735:Mifepristone; D016912:Levonorgestrel; C555622:ulipristal acetate
keywords: copper intrauterine device; emergency contraception; levonorgestrel; mifepristone; ulipristal acetate