Same-day start removes barriers to contraceptive initiation and may reduce the risk of unintended pregnancy. It may be appropriate for all contraceptive methods, but we lack data comparing methods. This study aimed to assess the frequency of same-day start with 6 contraceptive methods among new contraceptive users and describe the efficacy of same-day start in terms of first-cycle pregnancy risk overall and by each method. Using prospective data from the HER Salt Lake Contraceptive Initiative, we identified and assessed outcomes for participants initiating a new method of contraception beyond the first 7 days of their menstrual cycle (same-day start). Enrolled participants at 4 family planning clinics in Salt Lake County, Utah between September 2015 and March 2017 received their method of choice regardless of their cycle day or recent unprotected intercourse. All participants self-reported last menstrual period data and unprotected intercourse events in the previous 2 weeks. We excluded participants who received care immediately after or within 2 weeks of abortion care. Clinical electronic health records provided information on contraceptive method initiation and use of oral emergency contraception. Participants reported pregnancy outcomes in 1-, 3-, and 6-month follow-up surveys with clinic verification to identify any pregnancy resulting from same-day initiation. The primary outcomes report the frequency of same-day start use and first-cycle pregnancy risk among same-day start users of all contraceptive methods. The secondary outcomes include frequency of and pregnancy risk in the first cycle of use among same-day start contraception users by method. We also report the frequency of unprotected intercourse within 5 days and 6 to 14 days of contraception initiation, frequency of concomitant receipt of oral emergency contraception with initiation of ongoing contraception, and pregnancy risk with these exposures. We analyzed pregnancy risk for each contraceptive method initiated on the same day and assessed the simultaneous use of oral emergency contraception. Of the 3568 individuals enrolled, we identified most as same-day start users (n=2575/3568; 72.2%), with 1 in 8 of those reporting unprotected intercourse in the previous 5 days (n=322/2575; 12.5%) and 1 in 10 reporting unprotected intercourse 6 to 14 days before contraceptive method initiation (n=254/2575; 9.9%). We identified 11 pregnancies among same-day start users (0.4%; 95% confidence interval, 0.2–0.7), as opposed to 1 (0.1%; 95% confidence interval, 0.002–0.6) among those who initiated contraception within 7 days from the last menstrual period. Users of oral hormonal contraception and vaginal hormonal methods reported the highest first-cycle pregnancy rates (1.0–1.2). Among same-day start users, 174 (6.8%) received oral emergency contraception at enrollment in conjunction with another method. Among the same-day start users who received emergency contraception at initiation, 4 (2.3%) pregnancies were reported. Same-day start is common and associated with a low pregnancy risk. Using the “any method, any-time” approach better meets contraceptive clients’ needs and maintains a low risk of pregnancy.

中文翻译：

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当日开始避孕的频率、近期无保护性交和怀孕风险：多种避孕方法的前瞻性队列研究

当天开始消除了开始避孕的障碍，并可能降低意外怀孕的风险。它可能适用于所有避孕方法，但我们缺乏数据比较方法。本研究旨在评估新避孕药使用者当天开始使用 6 种避孕方法的频率，并描述当天开始使用每种方法对第一周期妊娠风险的总体效果。利用来自 HER 盐湖避孕计划的前瞻性数据，我们确定并评估了在月经周期前 7 天（当天开始）之后开始采用新避孕方法的参与者的结果。2015 年 9 月至 2017 年 3 月期间，在犹他州盐湖县 4 个计划生育诊所登记的参与者收到了他们选择的方法，无论其周期日或最近无保护性行为。所有参与者均自我报告末次月经数据和前两周无保护性交事件。我们排除了在堕胎护理后立即或两周内接受护理的参与者。临床电子健康记录提供了有关避孕方法启动和口服紧急避孕药使用的信息。参与者在 1、3 和 6 个月的跟踪调查中报告了妊娠结果，并进行了临床验证，以确定当天开始是否怀孕。主要结果报告了所有避孕方法的当日开始使用者的当日开始使用频率和第一周期妊娠风险。次要结果包括按方法划分的当日开始避孕使用者在第一个周期使用的频率和怀孕风险。我们还报告了开始避孕后 5 天内和 6 至 14 天内无保护性交的频率、开始持续避孕同时接受口服紧急避孕药的频率，以及这些暴露的怀孕风险。我们分析了当天开始的每种避孕方法的妊娠风险，并评估了同时使用口服紧急避孕药的情况。在注册的 3568 名个人中，我们确定大多数为当天开始使用者（n=2575/3568；72.2%），其中八分之一的人报告在过去 5 天内发生过无保护性行为（n=322/2575；12.5%）十分之一的人报告在开始避孕方法前 6 至 14 天进行了无保护性交（n=254/2575；9.9%）。我们在当天开始避孕的使用者中发现了 11 例怀孕（0.4%；95% 置信区间，0.2–0.7），而在 7 天内开始避孕的使用者中，只有 1 例（0.1%；95% 置信区间，0.002–0.6）。最后一次月经。口服激素避孕药和阴道激素避孕法的使用者报告第一周期妊娠率最高（1.0-1.2）。在当天开始使用的人中，174 人（6.8%）在入组时接受了口服紧急避孕药与另一种方法的结合。在开始时接受紧急避孕的当天开始使用者中，4（2. 3%）报告怀孕。当天开始很常见，并且怀孕风险较低。采用“任何方法、任何时间”的方式，更好地满足避孕客户的需求，保持较低的怀孕风险。