Nilsson C G, Lähteenmäki P, Luukkainen T
Contraception. 1980 Mar;21(3):225-33. doi: 10.1016/0010-7824(80)90003-7.
Plasma concentrations of levonorgestrel, progesterone, estradiol, FSH and LH were measured in seven volunteers who had a levonorgestrel-releasing IUD inserted postmenstrually. Blood samples were collected twice weekly during a mean of 93 days immediately postmenstrually and during a mean of 41 days over the twelfth to fifteenth month of treatment. Patterns of bleeding were studied during the first year of treatment. The IUDs used were designed to release 25 micrograms/day of levonorgestrel. The mean +/- SD plasma concentration of levonorgestrel for all subjects during the first three months was 260 +/- 68 pg/ml, and 129 +/- 28 pg/ml after one year of treatment. During the initial period of blood sampling only two of the subjects ovulated, while only two did not ovulate after one year of treatment. Intermenstrual spotting occurred during the first sixty days of treatment. Three subjects developed amenorrhea at the end of the first year. All the subjects continued the use of the IUD and no pregnancies occurred.
对7名在月经后插入左炔诺孕酮宫内节育器的志愿者，测定了其血浆中左炔诺孕酮、孕酮、雌二醇、促卵泡激素和促黄体生成素的浓度。在月经后立即进行的平均93天内，以及在治疗的第12至15个月的平均41天内，每周采集两次血样。在治疗的第一年研究了出血模式。所使用的宫内节育器设计为每天释放25微克左炔诺孕酮。所有受试者在头三个月的左炔诺孕酮平均血浆浓度（±标准差）为260±68皮克/毫升，治疗一年后为129±28皮克/毫升。在最初的采血期间，只有两名受试者排卵，而治疗一年后只有两名受试者未排卵。治疗的前60天出现了经间期点滴出血。三名受试者在第一年末出现闭经。所有受试者继续使用宫内节育器，未发生妊娠。
