Division of Clinical Research, Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine, St. Louis, Missouri.
Obstet Gynecol. 2013 Mar;121(3):585-592. doi: 10.1097/AOG.0b013e31828317cc.
To estimate weather contraceptive failure rates among combined oral contraceptive pill (OCP), patch, and vaginal ring users was associated with increasing body mass index (BMI).
Females enrolled in a large contraceptive study offering the reversible method of their choice at no cost were followed-up for 2-3 years. We compared the failure rates (pregnancy) among users of the OCP, transdermal patch, and contraceptive vaginal ring stratified by BMI.
Among the 7,486 participants available for this analysis, 1,523 chose OCPs, patch, or ring at enrollment. Of the 334 unintended pregnancies, 128 were found to be a result of OCP, patch, or ring failure. Three-year failure rates were not different across BMI categories (BMI less than 25 8.44%, 95% confidence interval [CI] 6.1-11.5; BMI 25-30 11.03%, 95% CI 7.5-16.0; BMI more than 30 8.92%, 95% confidence interval 7.6-11.5). Increasing parity (hazard ratio [HR] 3.06, CI 1.31-7.18) and history of a previous unintended pregnancy (HR 2.82, CI 1.63-4.87), but not BMI, were significant risk factors for unintended pregnancy.
Overweight and obese females do not appear to be at increased risk for contraceptive failure when using the OCP, patch, or vaginal ring.
评估体重指数（BMI）升高与复方口服避孕药（OCP）、贴剂和阴道环使用者的避孕失败率之间的关系。
在一项大型避孕研究中，选择了可免费提供的可逆避孕方法的女性入组，并随访 2-3 年。我们比较了 OCP、经皮贴剂和避孕阴道环使用者的避孕失败率（妊娠），并按 BMI 分层。
在可用于此分析的 7486 名参与者中，有 1523 名在入组时选择了 OCP、贴剂或环。在 334 例意外妊娠中，有 128 例是由于 OCP、贴剂或环失败所致。三年失败率在 BMI 类别之间没有差异（BMI<25 为 8.44%，95%置信区间[CI]为 6.1-11.5；BMI 25-30 为 11.03%，95%CI 为 7.5-16.0；BMI>30 为 8.92%，95%CI 为 7.6-11.5）。增加的产次（危险比[HR]3.06，95%CI 1.31-7.18）和既往意外妊娠史（HR 2.82，95%CI 1.63-4.87）是意外妊娠的显著危险因素，但 BMI 不是。
超重和肥胖女性使用 OCP、贴剂或阴道环时，似乎不会增加避孕失败的风险。
