Potter L S
Family Health International, Research Triangle Park, North Carolina, USA.
Obstet Gynecol. 1996 Sep;88(3 Suppl):13S-23S. doi: 10.1016/0029-7844(96)00246-3.
To provide an overview of contraceptive effectiveness and its determinants as well as reasons for the gap between the actual and expected number of unplanned pregnancies for various categories of users; to provide some guidelines for more precise, consistent terminology and measurements for use in future research; and to provide specific counseling guidelines; using combined oral contraceptives (OCs) as the example.
Fifty-three articles on contraceptive effectiveness were reviewed, with a particular focus on pregnancy rates among OC users and the quality of use contributing to those rates. Definitions and measurement of contraceptive effectiveness, its components, and its determinants were examined and discrepancies explored.
Papers discussed were selected because they had special relevance. Only a few of the papers discussed in this article were quantitative studies of contraceptive behavior and effectiveness. Others were review articles, discussions of the appropriate measurement of various components of effectiveness. Others provided conceptual frameworks for studying method effectiveness. All published studies of OC compliance were reviewed.
TABULATION, INTEGRATION, AND RESULTS: Comparing the definitions and measurement of both compliance and effectiveness revealed important inconsistencies. However, some trends did emerge, and these papers did provide a framework for the following discussion. The findings were used to develop a more coherent set of definitions, measurement approaches, and counseling strategies. Characteristics of the user, the method, and the service delivery system all play a role in contraceptive effectiveness. However, it is the quality of use, ie, the user's own behavior, that is the immediate determinant of the effectiveness of any short-term contraceptive method. The mean pregnancy rate for better-than-average users is 4%; for poorer-than-average users, it is 8%.
The range of contraceptive effectiveness rates is closely associated with user characteristics. Oral contraceptive users need to know that their own chance of becoming pregnant will vary with their fecundability, when and how frequently they have sexual intercourse, and, especially, how consistently and correctly they take their pills. The likelihood that any one user will take OCs correctly and consistently also is associated with her life-style, socioeconomic status, age, and other factors. Further research is needed to determine how forgiving OCs are of various pill-taking errors, to determine the impact of dual method use (eg, OCs and condoms), and to assess the effects of user, method, and programmatic characteristics on correct and consistent use and, in turn, on effectiveness.
概述避孕效果及其决定因素，以及各类使用者意外怀孕实际数量与预期数量之间存在差距的原因；为未来研究中使用更精确、一致的术语和测量方法提供一些指导方针；并以复方口服避孕药（OCs）为例提供具体的咨询指导方针。
对53篇关于避孕效果的文章进行了综述，特别关注口服避孕药使用者的怀孕率以及导致这些比率的使用质量。研究了避孕效果的定义、测量方法、其组成部分及其决定因素，并探讨了差异。
所讨论的论文因其具有特殊相关性而被选中。本文讨论的论文中只有少数是关于避孕行为和效果的定量研究。其他的是综述文章，讨论了效果各组成部分的适当测量方法。还有一些为研究方法效果提供了概念框架。对所有已发表的口服避孕药依从性研究进行了综述。
制表、整合与结果：比较依从性和效果的定义及测量方法，发现了重要的不一致之处。然而，确实出现了一些趋势，这些论文确实为后续讨论提供了一个框架。研究结果被用于制定一套更连贯的定义、测量方法和咨询策略。使用者、方法和服务提供系统的特征都对避孕效果有影响。然而，使用质量，即使用者自身的行为，才是任何短期避孕方法效果的直接决定因素。使用情况高于平均水平的使用者的平均怀孕率为4%；使用情况低于平均水平的使用者为8%。
避孕有效率的范围与使用者特征密切相关。口服避孕药使用者需要知道，他们怀孕的几率会因生育能力、性行为的时间和频率，尤其是服药的持续程度和正确性而有所不同。任何一位使用者正确、持续服用口服避孕药的可能性也与她的生活方式、社会经济地位、年龄及其他因素有关。需要进一步研究以确定口服避孕药对各种服药错误的宽容程度，确定同时使用两种方法（如口服避孕药和避孕套）的影响，并评估使用者、方法和项目特征对正确、持续使用以及进而对效果的影响。
