REFERENCES
- Luukkainen T, Lahteenmãki P, Toivonen J. Levonorgestrel-releasing intrauterine device. Ann Med 1990;22:85–90
- Luukkainen T, Alionen H, Haukkamaa M, et al. Five years' experience with levonorgestrel-releasing IUDS. Contraception 1986;33;139–48
- Nilsson CG, Lahteenmãki P, Luukkainen T, et al. Sustained intrauterine release of levonorgestrel over five years. Ferii'/ Steril 1986;45:805–7
- Andersson K, Odling V, Rybo G. Levonorgestrel-releasing and copper-releasing (Nova T) IUDs during five years of use: a randomised comparative trial. Contraception 1994;49:56–72
- Nilsson CG, Alionen H, Diaz J, et al. Two years experience with two levonorgestrel-releasing intrauterine devices and one copper-releasing intrauterine device: a randomised comparative performance study. Fértil Steril 1983;39:187–92
- Luukkainen T, Alionen H, Haukkamaa M, et al. Effective contraception with the levonorgestrel-releasing intrauterine device: 12-month report of a European multicenter study. Contraception 1987;35:169–79
- Sivin I, Stern J. Health during prolonged use of levonorgestrel 20 g/d and the Copper TCu 380 Ag intrauterine contraceptive devices: a multicenter study. Fértil Steril 1994;61:70–7
- Nilsson CG, Luukkainen T, Diaz J, et al. Intrauterine contraception with levonorgestrel: a comparative randomised clinical performance study. Lancet 1981;1: 577–80
- Backman T, Huhtala S, Blom T, et al. Length of use and symptoms associated with premature removal of the levonorgestrel intrauterine system: a nation-wide study of 17,360 users. Br J Obstet Gynaecol 2000;107:335–9
- Sivin I, Mahgoub SE, McCarthy T, et al. Long-term contraception with the levonorgestrel 20 meg/day (LNG-20) and the copper T 380Ag intrauterine devices: a five-year randomised study. Contraception 1990;42:361–78
- Xiao I, Gu S, Wang S, et al. Norplant and the levonorgestrel IUD in Chinese family planning programmes. Ann Med 1993;25:161–5
- Hatasaka H. Implantable levonorgestrel contraception: 4 years of experience with Norplant. Clin Obstet Gynecol 1995;38:859–71
- Vekemans M, Delvigne A, Paesmans M. Continuation rates with a levonorgestrel-releasing contraceptive implant (Norplant®). Contraception 1997;56:291–9