Sturridge F, Guillebaud J
Research Unit, Margaret Pyke Family Planning Centre, London, England.
Drug Saf. 1996 Dec;15(6):430-40. doi: 10.2165/00002018-199615060-00006.
The levonorgestrel-releasing intrauterine system (LNG-IUS), has been developed by Leiras Pharmaceuticals, Turku, Finland. It is a new systemic hormonal contraceptive that releases levonorgestrel 20 micrograms every 24 hours. The device provides fertility control comparable with that of female sterilisation, complete reversibility and convenience, and has an excellent tolerability record. The low dosage of levonorgestrel released by its unique delivery system ensures minimal hormone-related systemic adverse effects, which tend to be in the category of 'nuisance' rather than hazardous, and gradually diminish after the first few months of use. In some respects, the contraceptive characteristics of the LNG-IUS have over-shadowed a substantial range of noncontraceptive beneficial effects that are rarely seen with inert or copper-releasing intrauterine contraceptive devices (IUDs), and have important and positive gynaecological and public health implications. This applies particularly to the profound reduction in duration and quantity of menstrual bleeding, and alleviation of dysmenorrhoea, which are associated with the use of the device. Recent studies have shown that the LNG-IUS is effective in preventing endometrial proliferation associated with oral or transdermal estradiol therapy, and in inducing regression of endometrial hyperplasia. Further research is required to determine whether it has a role in regulating the growth of uterine fibroids, and preventing pelvic inflammatory disease. The unique unwanted noncontraceptive effects of the system, including possible development of functional ovarian cysts, and the relationship between menstrual bleeding pattern and ovarian function, also require better understanding, in order to offer appropriate patient counselling and maximise acceptability and continuation of use of the method.
左炔诺孕酮宫内节育系统（LNG-IUS）由芬兰图尔库的莱拉制药公司研发。它是一种新型的全身性激素避孕药，每24小时释放20微克左炔诺孕酮。该装置提供的生育控制效果与女性绝育相当，具有完全可逆性和便利性，且耐受性良好。其独特的给药系统释放的左炔诺孕酮剂量低，可确保与激素相关的全身性不良反应降至最低，这些不良反应往往属于“小麻烦”而非危险范畴，且在使用最初几个月后会逐渐减轻。在某些方面，LNG-IUS的避孕特性掩盖了一系列非避孕有益效果，而惰性或含铜宫内节育器（IUD）很少出现这些效果，且这些效果具有重要且积极的妇科和公共卫生意义。这尤其适用于与使用该装置相关的月经出血持续时间和出血量的大幅减少以及痛经的缓解。最近的研究表明，LNG-IUS在预防与口服或经皮雌二醇治疗相关的子宫内膜增生以及诱导子宫内膜增生消退方面有效。需要进一步研究以确定它在调节子宫肌瘤生长和预防盆腔炎方面是否发挥作用。该系统独特的非避孕不良影响，包括功能性卵巢囊肿的可能发生，以及月经出血模式与卵巢功能之间的关系，也需要更好地理解，以便提供适当的患者咨询并最大限度地提高该方法的可接受性和持续使用率。
