Review articleEmergency contraception: clinical outcomes
Introduction
Emergency contraception (EC) is used after intercourse to prevent unintended pregnancy either when no contraceptive method has been used or when an error in contraceptive use has been recognized — resulting, either way, in unprotected sexual intercourse. A number of methods of EC exist. Because each raises slightly different issues to do with effectiveness, accessibility and ease of use, this paper will discuss the clinical outcomes of the most commonly used oral method [levonorgestrel (LNG)], the newest oral method [ulipristal acetate (UPA)] and the most effective method [the copper intrauterine device (Cu-IUD)].
For treatment modalities for all conditions, the key questions relate to safety and efficacy, and one without the other is worthless. Side effects of any treatment are important for its acceptability but arguably much less important for a drug used as a one-off medication by someone highly motivated to prevent an unintended pregnancy with no other options for doing so at this time.
Section snippets
Safety and side effects
All methods of EC appear to be extremely safe.
Efficacy
There has never been a placebo-controlled trial of the efficacy of EC. Efficacy is estimated based on comparing the actual number of pregnancies occurring in a cohort of women using a method of EC with the number that might have been expected without EC use [11]. The expected number of pregnancies can only be a rough guess because it is based on estimating the risk of conception for each woman in the cohort on the reported cycle day of exposure (i.e., unprotected intercourse) related to her
Pregnancy rates with EC use
Whatever the exact number of pregnancies prevented, there can be little doubt that both oral LNG-EC and UPA and the Cu-IUD prevent some pregnancies in individual women. What has yet to be demonstrated, however, is the public health benefit of EC in reducing the number and rates of unintended pregnancies and induced abortions, and this is even harder to do. Paradoxically, indirect measurements of the effect of EC use on unintended pregnancy rates so far suggest a lack of effect. In many
Effect on risk-taking behavior and subsequent contraceptive use
In the discussions in the UK, which led eventually to deregulation of EC, those against the concept argued that giving women easier access to EC would increase its use at the expense of other methods of contraception [26]. It was suggested that the decrease in use of more effective methods would result in an increase, rather than a fall, in unintended pregnancies and abortions, Furthermore, the expected decline in condom use would, it was argued, increase the prevalence of STI. Such
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