Oakley D, Sereika S, Bogue E L
Center for Nursing Research, University of Michigan School of Nursing.
Fam Plann Perspect. 1991 Jul-Aug;23(4):150-4.
A retrospective study of 1,311 women making initial family planning visits to metropolitan-area health department clinics found that many women switch methods or discontinue use in the first year following the clinic visits. Among a subgroup of women, most of whom selected the pill as their primary method and who used the pill for at least one of the months in the study period, almost half either changed methods or used no method at some point during a follow-up period averaging eight months. This includes 13 percent of women who made two or more changes. In addition, only 42 percent said they took a pill every day, and only half of these said they always took their pill at about the same time every day. Despite such irregularities, pill users were approximately one-third as likely to get pregnant during the study period as women making an initial family planning visit to a health department clinic who did not use the pill at all.
一项对1311名首次前往大都市地区卫生部门诊所进行计划生育咨询的女性的回顾性研究发现，许多女性在诊所就诊后的第一年就更换了避孕方法或停止使用。在一个子群体的女性中，她们大多数选择口服避孕药作为主要避孕方法，并且在研究期间至少有一个月使用了口服避孕药，在平均为期八个月的随访期内，几乎有一半的女性在某些时候更换了避孕方法或停止使用。这其中包括13%更换了两种或更多避孕方法的女性。此外，只有42%的女性表示她们每天都服用避孕药，而这些女性中只有一半表示她们每天总是在大致相同的时间服药。尽管存在这些不规律情况，但在研究期间，口服避孕药的使用者怀孕的可能性大约只有那些首次前往卫生部门诊所进行计划生育咨询但根本未使用口服避孕药的女性的三分之一。
