Abstract: Background　The post-abortion care（PAC） service facilitates women's choice of high-efficiency contraceptive measures after induced abortion for ending unintended pregnancy. However，some of these women have been reported to abandon high-efficiency contraceptive measures that are first used after induced abortion in follow-up studies. Objective　To investigate the prevalence，causes and associated factors of abandoning high-efficiency contraceptive measures first used after induced abortion in women with unintended pregnancy. Methods　Participants were women who underwent induced abortion to end an unintended pregnancy in Zhejiang Provincial People's Hospital from January to December 2019. All of them received normal PAC services，and took combined oral contraception（COC） formulations or long-acting reversible contraception（LARC） after the surgery. Follow-ups were carried out at 1，3，6，9 and 12 months after menstruation recovery，including return visits，telephone follow-ups，WeChat follow-ups，and so on，to collect data for examining the prevalence，causes，and associated factors of abandoning the use of COC formulations or LARC during follow-up period，and the use of other contraceptive measures as well as unintended pregnancy incidence after the abandoning. Multivariate Logistic regression analysis was used to analyze the influencing factors of abandoning the use of COC formulations or LARC. Results　Altogether，346 cases who completed the study were finally included，and 259 of them（74.9%） used COC，and other 87（25.1%） used LARC for postoperative contraception. The prevalence of abandoning COC during the follow-ups after menstruation recovery was 14.3%-83.4%，showing an increasing trend（P<0.05）. The prevalence of abandoning LARC in the follow-ups after menstruation recovery was 0-19.5%. In those abandoning COC，80.3%（208/259） turned to non-high-efficiency contraceptive measures，and 3.1%（8/259） turned to LARC. In those abandoning LARC，11.5%（10/87） turned to non-high-efficiency contraceptive measures，and 8.0%（7/87） turned to COC. At the 12th month after menstruation recovery，the rate of abandoning COC in those using COC was higher than the rate of abandoning LARC in those using LARC（P<0.05）. And the rate of turning to non-high-efficiency contraception measures was also higher in those using COC（P<0.05）. The main reasons for abandoning COC were：difficulties taking the medicine regularly every day，adverse drug reactions and worrying about the impact on future fertility. The main reasons for abandoning LARC were：adverse drug reactions and complications ，and worrying about the impact on future fertility. Multivariate Logistic regression analysis showed that having reproductive history〔OR=0.492，95%CI（0.304，0.712）〕，repeated abortion〔OR=0.591，95%CI（0.315，0.893）〕 and positive contraceptive attitude〔OR=0.543，95%CI（0.246，0.912）〕were associated with reduced possibility of abandoning high-efficiency contraceptive measures after induced abortion for ending an unintended pregnancy，while younger age〔OR=1.782，95%CI（1.562，3.671）〕was associated with increased possibility（P<0.05）. Conclusion　In this group，the rate of abandoning COC first used after the induced abortion was high，while that of abandoning LARC was low. The major reasons for abandoning COC or LARC were poor adherence，adverse drug reactions，drug-related complications and concerns on future fertility. Age，reproductive history，repeated abortion and contraceptive attitude may be associated factors for the abandoning. So it is suggested to deliver postoperative follow-up services according to personal characteristics related to the abandoning to reduce the possibility of abandoning.

Key words: Abortion, induced；Pregnancy, unplanned；Contraceptives, oral, synthetic；Contraceptive devices, female；Contraceptive effectiveness；Root cause analysis

摘要： 背景　流产后关爱（PAC）服务促进意外妊娠女性人工流产术后（简称术后）高效避孕措施的选择，但随访发现部分患者后期会弃用原有的高效避孕措施。目的　了解意外妊娠术后高效避孕措施弃用状况，探究弃用原因及其相关影响因素。方法　选择2019年1—12月于浙江省人民医院因意外妊娠行人工流产术且术后选择复方口服避孕药（COC）或长效可逆避孕方法（LARC）两种高效避孕措施的女性为研究对象，均给予常规PAC宣教服务。分别于术后月经来潮后第1、3、6、9、12个月进行随访，随访形式包括返诊、电话、微信等。收集意外妊娠术后高效避孕措施弃用情况及原因、弃用后的避孕措施、意外妊娠情况，并采用多因素Logistic回归分析探究意外妊娠术后弃用高效避孕措施的影响因素。结果　共346例意外妊娠女性术后接受PAC服务后落实高效避孕措施并完成随访，其中选择COC 259例（74.9%），LARC 87例（25.1%）。意外妊娠术后月经来潮后第1、3、6、9、12个月COC弃用率为14.3%~83.4%、LARC弃用率为0~19.5%；术后各随访时间点COC弃用率随时间变化呈升高趋势（P<0.05）。弃用COC后，80.3%（208/259）的女性更换为非高效避孕措施，3.1%（8/259）的女性更换为LARC。弃用LARC后，11.5%（10/87）的女性更换为非高效避孕措施，8.0%（7/87）的女性更换为COC。术后月经来潮后第12个月，COC弃用率及更换非高效避孕措施率均高于LARC弃用率及更换非高效避孕措施率（P<0.05）。术后COC弃用的主要原因是难以坚持每天定时服药、药物不良反应及担心影响日后生育；LARC弃用的主要原因集中在放置后导致的不良反应和并发症，其次也有女性担心影响日后生育而弃用。多因素Logistic回归分析结果显示，生育史〔OR=0.492，95%CI（0.304，0.712）〕、重复流产〔OR=0.591，95%CI（0.315，0.893）〕及避孕态度〔OR=0.543，95%CI（0.246，0.912）〕是意外妊娠术后弃用原有高效避孕措施的保护因素，年龄〔OR=1.782，95%CI（1.562，3.671）〕是意外妊娠术后弃用原有高效避孕措施的危险因素（P<0.05）。结论　术后COC弃用率高，LARC相对稳定，术后女性弃用高效避孕措施的原因主要为难以坚持、药物不良反应、并发症及担心日后生育。年龄、生育史、重复流产及避孕态度是意外妊娠女性行人工流产术后弃用原有高效避孕措施的影响因素，因此，临床应根据上述特点做好术后持续个性化随访服务，以降低高效避孕措施的弃用。

关键词: 流产, 人工；妊娠, 意外；避孕药, 口服, 合成；避孕器械, 女性；避孕效果；影响因素分析