OBJECTIVE: 

To assess the Pearl Index for risk of ectopic pregnancy in women using levonorgestrel-releasing intrauterine systems (LNG-IUS) with hormonal reservoirs of 13.5 mg, 19.5 mg, or 52 mg.

METHODS: 

This was a retrospective cohort study. Women diagnosed with an ectopic pregnancy in Stockholm County, Sweden, between January 1, 2014, and December 31, 2019, were identified through the electronic medical record system. The final analysis included 2,252 cases of ectopic pregnancy. Information on age, reproductive and medical history, as well as current use of contraception was retrieved. The time of intrauterine device (IUD) insertion before ectopic pregnancy and the numbers of sold LNG-IUS during the study period were used to calculate the incidence rate for ectopic pregnancy during use per 100 woman-years (Pearl Index).

RESULTS: 

Among women with an ectopic pregnancy diagnosis, 105 presented with a known type of hormonal IUD in situ, of whom 94 were included in the calculations of the Pearl Index. The estimated Pearl Index for ectopic pregnancy was 0.136 (95% CI 0.106–0.176) for the LNG-IUS 13.5-mg, 0.037 (95% CI 0.021–0.067) for the LNG-IUS 19.5-mg, and 0.009 (95% CI 0.006–0.014) for the LNG-IUS 52-mg. With the 52-mg LNG-IUS as referent, the relative risk (RR) for ectopic pregnancy was higher during the first year for LNG 13.5-mg (RR 20.59, 95% CI 12.04–35.21), and for both 13.5-mg (RR 14.49, 95% CI 9.01–23.3) and 19.5-mg (RR 4.44, 95% CI 1.64–12.00) during the total study period.

CONCLUSION: 

The absolute risk of ectopic pregnancy during the use of LNG-IUS at any doses was low. The results show that the lower the dose of the IUD, the higher the risk of an ectopic pregnancy. Higher-dose LNG-IUS should be considered when providing contraceptive counseling to a woman with known risk factors for ectopic pregnancy who are considering a hormonal IUD.

中文翻译：

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13.5-mg、19.5-mg 和 52-mg 左炔诺孕酮释放宫内系统和异位妊娠风险

客观的： 

评估使用具有 13.5 mg、19.5 mg 或 52 mg 荷尔蒙储库的左炔诺孕酮宫内节育系统 (LNG-IUS) 的女性异位妊娠风险的珍珠指数。

方法： 

这是一项回顾性队列研究。通过电子病历系统确定了 2014 年 1 月 1 日至 2019 年 12 月 31 日期间在瑞典斯德哥尔摩县被诊断出宫外孕的女性。最终分析包括 2,252 例异位妊娠。检索了有关年龄、生殖和病史以及当前避孕措施的信息。以异位妊娠前宫内节育器（IUD）置入时间和研究期间销售的LNG-IUS数量计算每100名女性年使用期间异位妊娠的发生率（珍珠指数）。

结果： 

在被诊断为异位妊娠的女性中，105 人在原位接受了已知类型的激素宫内节育器，其中 94 人被包括在珍珠指数的计算中。LNG-IUS 13.5-mg 异位妊娠的估计珍珠指数为 0.136 (95% CI 0.106–0.176)，LNG-IUS 19.5-mg 为 0.037 (95% CI 0.021–0.067) 和 0.009 (95% CI 0.006–0.014) 用于 LNG-IUS 52-mg。以 52-mg LNG-IUS 为参照，LNG 13.5-mg (RR 20.59, 95% CI 12.04-35.21) 和 13.5-mg 第一年异位妊娠的相对风险 (RR) 较高。在整个研究期间，RR 14.49, 95% CI 9.01–23.3) 和 19.5-mg (RR 4.44, 95% CI 1.64–12.00)。

结论： 

使用任何剂量的 LNG-IUS 期间异位妊娠的绝对风险较低。结果表明，宫内节育器的剂量越低，异位妊娠的风险就越高。向正在考虑使用激素宫内节育器的已知异位妊娠危险因素的女性提供避孕咨询时，应考虑使用大剂量 LNG-IUS。