Levine Marc, Soon Judith A
Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver BC; Department of Pharmacy, Children's and Women's Hospitals of British Columbia, Vancouver BC.
Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver BC.
J Obstet Gynaecol Can. 2006 Oct;28(10):879-883. doi: 10.1016/S1701-2163(16)32276-9.
Recent revision of the method used to estimate risk of pregnancy among women requesting medication for emergency contraception (EC) suggests that the effectiveness of EC may be lower than is generally believed. We undertook a population-based study to estimate the risk of pregnancy among women requesting EC from pharmacists in British Columbia under conditions of routine care.
We obtained data on time since unprotected intercourse and medication provided for women in British Columbia requesting EC from January 1, 2001 to December 31, 2002.
More women obtained levonorgestrel (60.7%) than the Yuzpe regimen (39.3%) for EC, and of those reporting contraceptive failure, 90% requested EC because of condom failure. Overall, the estimated risk of pregnancy among the 11 795 women who obtained EC was 4.12 % (95% confidence interval 3.77-4.49).
Under routine conditions, the population-based predicted risk of pregnancy is lower than has previously been estimated. This suggests that the relative reduction in pregnancies achieved with EC is lower than is currently assumed by clinicians and patients.
近期对用于评估寻求紧急避孕（EC）药物的女性怀孕风险的方法进行的修订表明，紧急避孕的有效性可能低于普遍认为的水平。我们开展了一项基于人群的研究，以评估在常规护理条件下，不列颠哥伦比亚省向药剂师寻求紧急避孕的女性的怀孕风险。
我们获取了2001年1月1日至2002年12月31日期间，不列颠哥伦比亚省寻求紧急避孕的女性自无保护性交后的时间以及所提供药物的数据。
在使用紧急避孕的女性中，获得左炔诺孕酮的女性（60.7%）多于使用Yuzpe方案的女性（39.3%），在那些报告避孕失败的女性中，90%是因为避孕套失败而寻求紧急避孕。总体而言，在11795名获得紧急避孕的女性中，估计的怀孕风险为4.12%（95%置信区间3.77 - 4.49）。
在常规条件下，基于人群预测的怀孕风险低于先前的估计。这表明，紧急避孕实现的怀孕相对减少率低于临床医生和患者目前的假设。
